A family of proteins that promote unwinding of RNA during splicing and translation.
A large family of RNA helicases that share a common protein motif with the single letter amino acid sequence D-E-A-D (Asp-Glu-Ala-Asp). In addition to RNA helicase activity, members of the DEAD-box family participate in other aspects of RNA metabolism and regulation of RNA function.
Proteins that catalyze the unwinding of duplex DNA during replication by binding cooperatively to single-stranded regions of DNA or to short regions of duplex DNA that are undergoing transient opening. In addition DNA helicases are DNA-dependent ATPases that harness the free energy of ATP hydrolysis to translocate DNA strands.
A family of structurally-related DNA helicases that play an essential role in the maintenance of genome integrity. RecQ helicases were originally discovered in E COLI and are highly conserved across both prokaryotic and eukaryotic organisms. Genetic mutations that result in loss of RecQ helicase activity gives rise to disorders that are associated with CANCER predisposition and premature aging.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. EC 2.7.7.-.
The ultimate exclusion of nonsense sequences or intervening sequences (introns) before the final RNA transcript is sent to the cytoplasm.
Ribonucleic acid that makes up the genetic material of viruses.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
A component of eukaryotic initiation factor 4F that as an RNA helicase involved in unwinding the secondary structure of the 5' UNTRANSLATED REGION of MRNA. The unwinding facilitates the binding of the 40S ribosomal subunit.
RNA consisting of two strands as opposed to the more prevalent single-stranded RNA. Most of the double-stranded segments are formed from transcription of DNA by intramolecular base-pairing of inverted complementary sequences separated by a single-stranded loop. Some double-stranded segments of RNA are normal in all organisms.
Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A multifunctional protein that is both a DEAD-box RNA helicase and a component of the SMN protein complex.
The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)
RNA transcripts of the DNA that are in some unfinished stage of post-transcriptional processing (RNA PROCESSING, POST-TRANSCRIPTIONAL) required for function. RNA precursors may undergo several steps of RNA SPLICING during which the phosphodiester bonds at exon-intron boundaries are cleaved and the introns are excised. Consequently a new bond is formed between the ends of the exons. Resulting mature RNAs can then be used; for example, mature mRNA (RNA, MESSENGER) is used as a template for protein production.
Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
A process that changes the nucleotide sequence of mRNA from that of the DNA template encoding it. Some major classes of RNA editing are as follows: 1, the conversion of cytosine to uracil in mRNA; 2, the addition of variable number of guanines at pre-determined sites; and 3, the addition and deletion of uracils, templated by guide-RNAs (RNA, GUIDE).
Biological properties, processes, and activities of VIRUSES.
The extent to which an RNA molecule retains its structural integrity and resists degradation by RNASE, and base-catalyzed HYDROLYSIS, under changing in vivo or in vitro conditions.
Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.
A family of DNA helicases that participate in DNA REPLICATION. They assemble into hexameric rings with a central channel and unwind DNA processively in the 5' to 3' direction. DnaB helicases are considered the primary replicative helicases for most prokaryotic organisms.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.
Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.
Proteins that bind to RNA molecules. Included here are RIBONUCLEOPROTEINS and other proteins whose function is to bind specifically to RNA.
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
An autosomal recessive disorder characterized by telangiectatic ERYTHEMA of the face, photosensitivity, DWARFISM and other abnormalities, and a predisposition toward developing cancer. The Bloom syndrome gene (BLM) encodes a RecQ-like DNA helicase.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Viruses whose genetic material is RNA.
Enzymes that catalyze DNA template-directed extension of the 3'-end of an RNA strand one nucleotide at a time. They can initiate a chain de novo. In eukaryotes, three forms of the enzyme have been distinguished on the basis of sensitivity to alpha-amanitin, and the type of RNA synthesized. (From Enzyme Nomenclature, 1992).
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
An autosomal recessive disorder that causes premature aging in adults, characterized by sclerodermal skin changes, cataracts, subcutaneous calcification, muscular atrophy, a tendency to diabetes mellitus, aged appearance of the face, baldness, and a high incidence of neoplastic disease.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
An absence of warmth or heat or a temperature notably below an accustomed norm.
Complexes of RNA-binding proteins with ribonucleic acids (RNA).
The process of cleaving a chemical compound by the addition of a molecule of water.
A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. It functions in the nucleoplasmic structure and transcribes DNA into RNA. It has different requirements for cations and salt than RNA polymerase I and is strongly inhibited by alpha-amanitin. EC 2.7.7.6.
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
The process of intracellular viral multiplication, consisting of the synthesis of PROTEINS; NUCLEIC ACIDS; and sometimes LIPIDS, and their assembly into a new infectious particle.
RNA that has catalytic activity. The catalytic RNA sequence folds to form a complex surface that can function as an enzyme in reactions with itself and other molecules. It may function even in the absence of protein. There are numerous examples of RNA species that are acted upon by catalytic RNA, however the scope of this enzyme class is not limited to a particular type of substrate.
The processes of RNA tertiary structure formation.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A family of enzymes that catalyze the exonucleolytic cleavage of DNA. It includes members of the class EC 3.1.11 that produce 5'-phosphomonoesters as cleavage products.
The process by which a DNA molecule is duplicated.
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Established cell cultures that have the potential to propagate indefinitely.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
An autosomal recessive syndrome occurring principally in females, characterized by the presence of reticulated, atrophic, hyperpigmented, telangiectatic cutaneous plaques, often accompanied by juvenile cataracts, saddle nose, congenital bone defects, disturbances in the growth of HAIR; NAILS; and TEETH; and HYPOGONADISM.
The functional hereditary units of FUNGI.
RNA molecules which hybridize to complementary sequences in either RNA or DNA altering the function of the latter. Endogenous antisense RNAs function as regulators of gene expression by a variety of mechanisms. Synthetic antisense RNAs are used to effect the functioning of specific genes for investigative or therapeutic purposes.
A single chain of deoxyribonucleotides that occurs in some bacteria and viruses. It usually exists as a covalently closed circle.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
Short chains of RNA (100-300 nucleotides long) that are abundant in the nucleus and usually complexed with proteins in snRNPs (RIBONUCLEOPROTEINS, SMALL NUCLEAR). Many function in the processing of messenger RNA precursors. Others, the snoRNAs (RNA, SMALL NUCLEOLAR), are involved with the processing of ribosomal RNA precursors.
The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from the presence of naturally occurring ANTI-INFECTIVE AGENTS, constitutional factors such as BODY TEMPERATURE and immediate acting immune cells such as NATURAL KILLER CELLS.
RNA which does not code for protein but has some enzymatic, structural or regulatory function. Although ribosomal RNA (RNA, RIBOSOMAL) and transfer RNA (RNA, TRANSFER) are also untranslated RNAs they are not included in this scope.
Proteins found in any species of fungus.
Nucleic acid structures found on the 5' end of eukaryotic cellular and viral messenger RNA and some heterogeneous nuclear RNAs. These structures, which are positively charged, protect the above specified RNAs at their termini against attack by phosphatases and other nucleases and promote mRNA function at the level of initiation of translation. Analogs of the RNA caps (RNA CAP ANALOGS), which lack the positive charge, inhibit the initiation of protein synthesis.
An enzyme which catalyzes the hydrolysis of nucleoside triphosphates to nucleoside diphosphates. It may also catalyze the hydrolysis of nucleotide triphosphates, diphosphates, thiamine diphosphates and FAD. The nucleoside triphosphate phosphohydrolases I and II are subtypes of the enzyme which are found mostly in viruses.
A multistage process that includes cloning, physical mapping, subcloning, sequencing, and information analysis of an RNA SEQUENCE.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.
Proteins obtained from ESCHERICHIA COLI.
Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.
An increased tendency of the GENOME to acquire MUTATIONS when various processes involved in maintaining and replicating the genome are dysfunctional.
The reconstruction of a continuous two-stranded DNA molecule without mismatch from a molecule which contained damaged regions. The major repair mechanisms are excision repair, in which defective regions in one strand are excised and resynthesized using the complementary base pairing information in the intact strand; photoreactivation repair, in which the lethal and mutagenic effects of ultraviolet light are eliminated; and post-replication repair, in which the primary lesions are not repaired, but the gaps in one daughter duplex are filled in by incorporation of portions of the other (undamaged) daughter duplex. Excision repair and post-replication repair are sometimes referred to as "dark repair" because they do not require light.
RNA present in neoplastic tissue.
The process of moving specific RNA molecules from one cellular compartment or region to another by various sorting and transport mechanisms.
Changes in the organism associated with senescence, occurring at an accelerated rate.

The Caenorhabditis elegans sex determination gene mog-1 encodes a member of the DEAH-Box protein family. (1/1563)

In the Caenorhabditis elegans hermaphrodite germ line, the sex-determining gene fem-3 is repressed posttranscriptionally to arrest spermatogenesis and permit oogenesis. This repression requires a cis-acting regulatory element in the fem-3 3' untranslated region; the FBF protein, which binds to this element; and at least six mog genes. In this paper, we report the molecular characterization of mog-1 as well as additional phenotypic characterization of this gene. The mog-1 gene encodes a member of the DEAH-box family. Three mog-1 alleles possess premature stop codons and are likely to be null alleles, and one is a missense mutation and is likely to retain residual activity. mog-1 mRNA is expressed in both germ line and somatic tissues and appears to be ubiquitous. The MOG-1 DEAH-box protein is most closely related to proteins essential for splicing in the yeast Saccharomyces cerevisiae, but splicing appears to occur normally in a mog-1-null mutant. In addition to its involvement in the sperm-oocyte switch and control of fem-3, zygotic mog-1 is required for robust germ line proliferation and for normal growth during development. We suggest that mog-1 plays a broader role in RNA regulation than previously considered.  (+info)

Dengue virus NS3 serine protease. Crystal structure and insights into interaction of the active site with substrates by molecular modeling and structural analysis of mutational effects. (2/1563)

The mosquito-borne dengue viruses are widespread human pathogens causing dengue fever, dengue hemorrhagic fever, and dengue shock syndrome, placing 40% of the world's population at risk with no effective treatment. The viral genome is a positive strand RNA that encodes a single polyprotein precursor. Processing of the polyprotein precursor into mature proteins is carried out by the host signal peptidase and by NS3 serine protease, which requires NS2B as a cofactor. We report here the crystal structure of the NS3 serine protease domain at 2.1 A resolution. This structure of the protease combined with modeling of peptide substrates into the active site suggests identities of residues involved in substrate recognition as well as providing a structural basis for several mutational effects on enzyme activity. This structure will be useful for development of specific inhibitors as therapeutics against dengue and other flaviviral proteases.  (+info)

A cold shock-induced cyanobacterial RNA helicase. (3/1563)

The ability to modify RNA secondary structure is crucial for numerous cellular processes. We have characterized two RNA helicase genes, crhB and crhC, which are differentially expressed in the cyanobacterium Anabaena sp. strain PCC 7120. crhC transcription is limited specifically to cold shock conditions while crhB is expressed under a variety of conditions, including enhanced expression in the cold. This implies that both RNA helicases are involved in the cold acclimation process in cyanobacteria; however, they presumably perform different roles in this adaptation. Although both CrhB and CrhC belong to the DEAD box subfamily of RNA helicases, CrhC encodes a novel RNA helicase, as the highly conserved SAT motif is modified to FAT. This alteration may affect CrhC function and its association with specific RNA targets and/or accessory proteins, interactions required for cold acclimation. Primer extension and analysis of the 5' untranslated region of crhC revealed the transcriptional start site, as well as a number of putative cold shock-responsive elements. The potential role(s) performed by RNA helicases in the acclimation of cyanobacteria to cold shock is discussed.  (+info)

Hepatitis C virus core protein interacts with cellular putative RNA helicase. (4/1563)

The nucleocapsid core protein of hepatitis C virus (HCV) has been shown to trans-act on several viral or cellular promoters. To get insight into the trans-action mechanism of HCV core protein, a yeast two-hybrid cloning system was used for identification of core protein-interacting cellular protein. One such cDNA clone encoding the DEAD box family of putative RNA helicase was obtained. This cellular putative RNA helicase, designated CAP-Rf, exhibits more than 95% amino acid sequence identity to other known RNA helicases including human DBX and DBY, mouse mDEAD3, and PL10, a family of proteins generally involved in translation, splicing, development, or cell growth. In vitro binding or in vivo coimmunoprecipitation studies demonstrated the direct interaction of the full-length/matured form and C-terminally truncated variants of HCV core protein with this targeted protein. Additionally, the protein's interaction domains were delineated at the N-terminal 40-amino-acid segment of the HCV core protein and the C-terminal tail of CAP-Rf, which encompassed its RNA-binding and ATP hydrolysis domains. Immunoblotting or indirect immunofluorescence analysis revealed that the endogenous CAP-Rf was mainly localized in the nucleus and to a lesser extent in the cytoplasm, and when fused with FLAG tag, it colocalized with the HCV core protein either in the cytoplasm or in the nucleus. Similar to other RNA helicases, this cellular RNA helicase has nucleoside triphosphatase-deoxynucleoside triphosphatase activity, but this activity is inhibited by various forms of homopolynucleotides and enhanced by the HCV core protein. Moreover, transient expression of HCV core protein in human hepatoma HuH-7 cells significantly potentiated the trans-activation effect of FLAG-tagged CAP-Rf or untagged CAP-Rf on the luciferase reporter plasmid activity. All together, our results indicate that CAP-Rf is involved in regulation of gene expression and that HCV core protein promotes the trans-activation ability of CAP-Rf, likely via the complex formation and the modulation of the ATPase-dATPase activity of CAP-Rf. These findings provide evidence that HCV may have evolved a distinct mechanism in alteration of host cellular gene expression regulation via the interaction of its nucleocapsid core protein and cellular putative RNA helicase known to participate in all aspects of cellular processes involving RNA metabolism. This feature of core protein may impart pleiotropic effects on host cells, which may partially account for its role in HCV pathogenesis.  (+info)

RNA-Stimulated ATPase and RNA helicase activities and RNA binding domain of hepatitis G virus nonstructural protein 3. (5/1563)

Hepatitis G virus (HGV) nonstructural protein 3 (NS3) contains amino acid sequence motifs typical of ATPase and RNA helicase proteins. In order to examine the RNA helicase activity of the HGV NS3 protein, the NS3 region (amino acids 904 to 1580) was fused with maltose-binding protein (MBP), and the fusion protein was expressed in Escherichia coli and purified with amylose resin and anion-exchange chromatography. The purified MBP-HGV/NS3 protein possessed RNA-stimulated ATPase and RNA helicase activities. Characterization of the ATPase and RNA helicase activities of MBP-HGV/NS3 showed that the optimal reaction conditions were similar to those of other Flaviviridae viral NS3 proteins. However, the kinetic analysis of NTPase activity showed that the MBP-HGV/NS3 protein had several unique properties compared to the other Flaviviridae NS3 proteins. The HGV NS3 helicase unwinds RNA-RNA duplexes in a 3'-to-5' direction and can unwind RNA-DNA heteroduplexes and DNA-DNA duplexes as well. In a gel retardation assay, the MBP-HGV/NS3 helicase bound to RNA, RNA/DNA, and DNA duplexes with 5' and 3' overhangs but not to blunt-ended RNA duplexes. We also found that the conserved motif VI was important for RNA binding. Further deletion mapping showed that the RNA binding domain was located between residues 1383 and 1395, QRRGRTGRGRSGR. Our data showed that the MBP-HCV/NS3 protein also contains the RNA binding domain in the similar domain.  (+info)

The serine protease and RNA-stimulated nucleoside triphosphatase and RNA helicase functional domains of dengue virus type 2 NS3 converge within a region of 20 amino acids. (6/1563)

NS3 protein of dengue virus type 2 has a serine protease domain within the N-terminal 180 residues. NS2B is required for NS3 to form an active protease involved in processing of the viral polyprotein precursor. The region carboxy terminal to the protease domain has conserved motifs present in several viral RNA-stimulated nucleoside triphosphatase (NTPase)/RNA helicases. To define the functional domains of protease and NTPase/RNA helicase activities of NS3, full-length and amino-terminal deletion mutants of NS3 were expressed in Escherichia coli and purified. Deletion of 160 N-terminal residues of NS3 (as in NS3del.2) had no detrimental effect on the basal and RNA-stimulated NTPase as well as RNA helicase activities. However, mutagenesis of the conserved P-loop motif of the RNA helicase domain (K199E) resulted in loss of ATPase activity. The RNA-stimulated NTPase activity was significantly affected by deletion of 20 amino acid residues from the N terminus or by substitutions of the cluster of basic residues, 184RKRK-->QNGN, of NS3del.2, although both mutant proteins retained the conserved RNA helicase motifs. Furthermore, the minimal NS3 protease domain, required for cleavage of the 2B-3 site, was precisely defined to be 167 residues, using the in vitro processing of NS2B-NS3 precursors. Our results reveal that the functional domains required for serine protease and RNA-stimulated NTPase activities map within the region between amino acid residues 160 and 180 of NS3 protein and that a novel motif, the cluster of basic residues 184RKRK, plays an important role for the RNA-stimulated NTPase activity.  (+info)

A multigene locus containing the Manx and bobcat genes is required for development of chordate features in the ascidian tadpole larva. (7/1563)

The Manx gene is required for the development of the tail and other chordate features in the ascidian tadpole larva. To determine the structure of the Manx gene, we isolated and sequenced genomic clones from the tailed ascidian Molgula oculata. The Manx gene contains 9 exons and encodes both major and minor Manx mRNAs, which differ in the length of their 5' untranslated regions. The coding region of the single-copy bobcat gene, which encodes a DEAD-box RNA helicase, is embedded within the first Manx intron. The organization of the bobcat and Manx transcription units was determined by comparing genomic and cDNA clones. The Manx-bobcat gene locus has an unusual organization in which a non-coding first exon is alternatively spliced at the 5' end of two different mRNAs. The bobcat and Manx genes are expressed coordinately during oogenesis and embryogenesis, but not during spermatogenesis, in which bobcat mRNA accumulates independently of Manx mRNA. Similar to Manx, zygotic bobcat transcripts accumulate in the embryonic primordia responsible for generating chordate features, including the dorsal neural tube and notochord, are downregulated during embryogenesis in the tailless species Molgula occulta and are upregulated in M. occulta X M. oculata hybrids, which restore these chordate features. Antisense experiments indicate that zygotic bobcat expression is required for development of the same suite of chordate features as Manx. The results show that the Manx-bobcat gene complex has a role in the development of chordate features in ascidian tadpole larvae.  (+info)

DNA binding protein dbpA binds Cdk5 and inhibits its activity. (8/1563)

Progress in the cell cycle is governed by the activity of cyclin dependent kinases (Cdks). Unlike other Cdks, the Cdk5 catalytic subunit is found mostly in differentiated neurons. Interestingly, the only known protein that activates Cdk5 (i.e. p35) is expressed solely in the brain. It has been suggested that, besides its requirement in neuronal differentiation, Cdk5 activity is induced during myogenesis. However, it is not clear how this activity is regulated in the pathway that leads proliferative cells to differentiation. In order to find if there exists any Cdk5-interacting protein, the yeast two-hybrid system was used to screen a HeLa cDNA library. We have determined that a C-terminal 172 amino acid domain of the DNA binding protein, dbpA, binds to Cdk5. Biochemical analyses reveal that this fragment (dbpA(Cdelta)) strongly inhibits p35-activated Cdk5 kinase. The protein also interacts with Cdk4 and inhibits the Cdk4/cyclin D1 enzyme. Surprisingly, dbpA(Cdelta) does not bind Cdk2 in the two-hybrid assay nor does it inhibit Cdk2 activated by cyclin A. It could be that dbpA's ability to inhibit Cdk5 and Cdk4 reflects an apparent cross-talk between distinct signal transduction pathways controlled by dbpA on the one hand and Cdk5 or Cdk4 on the other.  (+info)

RNA helicases are a class of enzymes that are capable of unwinding RNA secondary structures using the energy derived from ATP hydrolysis. They play crucial roles in various cellular processes involving RNA, such as transcription, splicing, translation, ribosome biogenesis, and RNA degradation. RNA helicases can be divided into several superfamilies based on their sequence and structural similarities, with the two largest being superfamily 1 (SF1) and superfamily 2 (SF2). These enzymes typically contain conserved motifs that are involved in ATP binding and hydrolysis, as well as RNA binding. By unwinding RNA structures, RNA helicases facilitate the access of other proteins to their target RNAs, thereby enabling the coordinated regulation of RNA metabolism.

DEAD-box RNA helicases are a family of proteins that are involved in unwinding RNA secondary structures and displacing proteins bound to RNA molecules. They get their name from the conserved amino acid sequence motif "DEAD" (Asp-Glu-Ala-Asp) found within their catalytic core, which is responsible for ATP-dependent helicase activity. These enzymes play crucial roles in various aspects of RNA metabolism, including pre-mRNA splicing, ribosome biogenesis, translation initiation, and RNA decay. DEAD-box helicases are also implicated in a number of human diseases, such as cancer and neurological disorders.

DNA helicases are a group of enzymes that are responsible for separating the two strands of DNA during processes such as replication and transcription. They do this by unwinding the double helix structure of DNA, using energy from ATP to break the hydrogen bonds between the base pairs. This allows other proteins to access the individual strands of DNA and carry out functions such as copying the genetic code or transcribing it into RNA.

During replication, DNA helicases help to create a replication fork, where the two strands of DNA are separated and new complementary strands are synthesized. In transcription, DNA helicases help to unwind the DNA double helix at the promoter region, allowing the RNA polymerase enzyme to bind and begin transcribing the DNA into RNA.

DNA helicases play a crucial role in maintaining the integrity of the genetic code and are essential for the normal functioning of cells. Defects in DNA helicases have been linked to various diseases, including cancer and neurological disorders.

RecQ helicases are a group of enzymes that belong to the RecQ family, which are named after the E. coli RecQ protein. These helicases play crucial roles in maintaining genomic stability by participating in various DNA metabolic processes such as DNA replication, repair, recombination, and transcription. They are highly conserved across different species, including bacteria, yeast, plants, and mammals.

In humans, there are five RecQ helicases: RECQL1, RECQL4, RECQL5, BLM (RecQ-like helicase), and WRN (Werner syndrome ATP-dependent helicase). Defects in these proteins have been linked to various genetic disorders. For instance, mutations in the BLM gene cause Bloom's syndrome, while mutations in the WRN gene lead to Werner syndrome, both of which are characterized by genomic instability and increased cancer predisposition.

RecQ helicases possess 3'-5' DNA helicase activity, unwinding double-stranded DNA into single strands, and can also perform other functions like branch migration, strand annealing, and removal of protein-DNA crosslinks. Their roles in DNA metabolism help prevent and resolve DNA damage, maintain proper chromosome segregation during cell division, and ensure the integrity of the genome.

RNA (Ribonucleic Acid) is a single-stranded, linear polymer of ribonucleotides. It is a nucleic acid present in the cells of all living organisms and some viruses. RNAs play crucial roles in various biological processes such as protein synthesis, gene regulation, and cellular signaling. There are several types of RNA including messenger RNA (mRNA), ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA), microRNA (miRNA), and long non-coding RNA (lncRNA). These RNAs differ in their structure, function, and location within the cell.

RNA nucleotidyltransferases are a class of enzymes that catalyze the template-independent addition of nucleotides to the 3' end of RNA molecules, using nucleoside triphosphates as substrates. These enzymes play crucial roles in various biological processes, including RNA maturation, quality control, and regulation.

The reaction catalyzed by RNA nucleotidyltransferases involves the formation of a phosphodiester bond between the 3'-hydroxyl group of the RNA substrate and the alpha-phosphate group of the incoming nucleoside triphosphate. This results in the elongation of the RNA molecule by one or more nucleotides, depending on the specific enzyme and context.

Examples of RNA nucleotidyltransferases include poly(A) polymerases, which add poly(A) tails to mRNAs during processing, and terminal transferases, which are involved in DNA repair and V(D)J recombination in the immune system. These enzymes have been implicated in various diseases, including cancer and neurological disorders, making them potential targets for therapeutic intervention.

RNA splicing is a post-transcriptional modification process in which the non-coding sequences (introns) are removed and the coding sequences (exons) are joined together in a messenger RNA (mRNA) molecule. This results in a continuous mRNA sequence that can be translated into a single protein. Alternative splicing, where different combinations of exons are included or excluded, allows for the creation of multiple proteins from a single gene.

A viral RNA (ribonucleic acid) is the genetic material found in certain types of viruses, as opposed to viruses that contain DNA (deoxyribonucleic acid). These viruses are known as RNA viruses. The RNA can be single-stranded or double-stranded and can exist as several different forms, such as positive-sense, negative-sense, or ambisense RNA. Upon infecting a host cell, the viral RNA uses the host's cellular machinery to translate the genetic information into proteins, leading to the production of new virus particles and the continuation of the viral life cycle. Examples of human diseases caused by RNA viruses include influenza, COVID-19 (SARS-CoV-2), hepatitis C, and polio.

Adenosine triphosphatases (ATPases) are a group of enzymes that catalyze the conversion of adenosine triphosphate (ATP) into adenosine diphosphate (ADP) and inorganic phosphate. This reaction releases energy, which is used to drive various cellular processes such as muscle contraction, transport of ions across membranes, and synthesis of proteins and nucleic acids.

ATPases are classified into several types based on their structure, function, and mechanism of action. Some examples include:

1. P-type ATPases: These ATPases form a phosphorylated intermediate during the reaction cycle and are involved in the transport of ions across membranes, such as the sodium-potassium pump and calcium pumps.
2. F-type ATPases: These ATPases are found in mitochondria, chloroplasts, and bacteria, and are responsible for generating a proton gradient across the membrane, which is used to synthesize ATP.
3. V-type ATPases: These ATPases are found in vacuolar membranes and endomembranes, and are involved in acidification of intracellular compartments.
4. A-type ATPases: These ATPases are found in the plasma membrane and are involved in various functions such as cell signaling and ion transport.

Overall, ATPases play a crucial role in maintaining the energy balance of cells and regulating various physiological processes.

Eukaryotic Initiation Factor-4A (eIF4A) is a type of protein involved in the process of gene expression in eukaryotic cells. More specifically, it is an initiation factor that plays a crucial role in the beginning stages of translation, which is the process by which the genetic information contained within messenger RNA (mRNA) molecules is translated into proteins.

eIF4A is a member of the DEAD-box family of RNA helicases, which are enzymes that use ATP to unwind and remodel RNA structures. In the context of translation, eIF4A helps to unwind secondary structures in the 5' untranslated region (5' UTR) of mRNAs, allowing the ribosome to bind and initiate translation.

eIF4A typically functions as part of a larger complex called eIF4F, which also includes eIF4E and eIF4G. Together, these proteins help to recruit the ribosome to the mRNA and facilitate the initiation of translation. Dysregulation of eIF4A and other initiation factors has been implicated in various diseases, including cancer.

I'm happy to help! However, it seems there might be a slight misunderstanding in your question. RNA, or ribonucleic acid, is typically single-stranded. Unlike DNA, which is double-stranded and forms a double helix, RNA usually exists as a single strand of nucleotides.

There are exceptions to this rule, such as certain types of RNA molecules that can form double-stranded structures in specific contexts. For example:

1. Double-Stranded RNA (dsRNA) viruses: These viruses have genomes made entirely of RNA, which is double-stranded throughout or partially double-stranded. The dsRNA viruses include important pathogens such as rotaviruses and reoviruses.
2. Hairpin loops in RNA structures: Some single-stranded RNA molecules can fold back on themselves to form short double-stranded regions, called hairpin loops, within their overall structure. These are often found in ribosomal RNA (rRNA), transfer RNA (tRNA), and messenger RNA (mRNA) molecules.

So, while 'double-stranded RNA' is not a standard medical definition for RNA itself, there are specific instances where RNA can form double-stranded structures as described above.

Small interfering RNA (siRNA) is a type of short, double-stranded RNA molecule that plays a role in the RNA interference (RNAi) pathway. The RNAi pathway is a natural cellular process that regulates gene expression by targeting and destroying specific messenger RNA (mRNA) molecules, thereby preventing the translation of those mRNAs into proteins.

SiRNAs are typically 20-25 base pairs in length and are generated from longer double-stranded RNA precursors called hairpin RNAs or dsRNAs by an enzyme called Dicer. Once generated, siRNAs associate with a protein complex called the RNA-induced silencing complex (RISC), which uses one strand of the siRNA (the guide strand) to recognize and bind to complementary sequences in the target mRNA. The RISC then cleaves the target mRNA, leading to its degradation and the inhibition of protein synthesis.

SiRNAs have emerged as a powerful tool for studying gene function and have shown promise as therapeutic agents for a variety of diseases, including viral infections, cancer, and genetic disorders. However, their use as therapeutics is still in the early stages of development, and there are challenges associated with delivering siRNAs to specific cells and tissues in the body.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

DEAD-Box Protein 20 (DDX20) is a member of the DEAD-box protein family, which are named for the conserved amino acid sequence "Asp-Glu-Ala-Asp" within their helicase domains. These proteins are involved in various aspects of RNA metabolism, including splicing, transport, translation, and degradation.

DDX20, also known as p68 or DP103, is a DNA/RNA helicase that plays a role in transcriptional regulation, pre-mRNA processing, and RNA export. It has been implicated in several cellular processes, including cell cycle progression, differentiation, and apoptosis. DDX20 can interact with various proteins involved in transcription, such as RNA polymerase II and the basal transcription factor TFIID, as well as components of the spliceosome and other RNA-binding proteins.

Mutations or dysregulation of DDX20 have been associated with several human diseases, including cancer, neurodevelopmental disorders, and autoimmune diseases. For example, increased expression of DDX20 has been observed in various types of cancer, such as breast, lung, and ovarian cancers, and may contribute to tumor progression by promoting cell proliferation and inhibiting apoptosis. Additionally, mutations in the gene encoding DDX20 have been identified in patients with intellectual disability, epilepsy, and autism spectrum disorder.

Ribosomal RNA (rRNA) is a type of RNA molecule that is a key component of ribosomes, which are the cellular structures where protein synthesis occurs in cells. In ribosomes, rRNA plays a crucial role in the process of translation, where genetic information from messenger RNA (mRNA) is translated into proteins.

Ribosomal RNA is synthesized in the nucleus and then transported to the cytoplasm, where it assembles with ribosomal proteins to form ribosomes. Within the ribosome, rRNA provides a structural framework for the assembly of the ribosome and also plays an active role in catalyzing the formation of peptide bonds between amino acids during protein synthesis.

There are several different types of rRNA molecules, including 5S, 5.8S, 18S, and 28S rRNA, which vary in size and function. These rRNA molecules are highly conserved across different species, indicating their essential role in protein synthesis and cellular function.

RNA precursors, also known as primary transcripts or pre-messenger RNAs (pre-mRNAs), refer to the initial RNA molecules that are synthesized during the transcription process in which DNA is copied into RNA. These precursor molecules still contain non-coding sequences and introns, which need to be removed through a process called splicing, before they can become mature and functional RNAs such as messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), or transfer RNAs (tRNAs).

Pre-mRNAs undergo several processing steps, including 5' capping, 3' polyadenylation, and splicing, to generate mature mRNA molecules that can be translated into proteins. The accurate and efficient production of RNA precursors and their subsequent processing are crucial for gene expression and regulation in cells.

Ribonucleic acid (RNA) is a type of nucleic acid that plays a crucial role in the process of gene expression. There are several types of RNA molecules, including messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). These RNA molecules help to transcribe DNA into mRNA, which is then translated into proteins by the ribosomes.

Fungi are a group of eukaryotic organisms that include microorganisms such as yeasts and molds, as well as larger organisms like mushrooms. Like other eukaryotes, fungi contain DNA and RNA as part of their genetic material. The RNA in fungi is similar to the RNA found in other organisms, including humans, and plays a role in gene expression and protein synthesis.

A specific medical definition of "RNA, fungal" does not exist, as RNA is a fundamental component of all living organisms, including fungi. However, RNA can be used as a target for antifungal drugs, as certain enzymes involved in RNA synthesis and processing are unique to fungi and can be inhibited by these drugs. For example, the antifungal drug flucytosine is converted into a toxic metabolite that inhibits fungal RNA and DNA synthesis.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

RNA editing is a process that alters the sequence of a transcribed RNA molecule after it has been synthesized from DNA, but before it is translated into protein. This can result in changes to the amino acid sequence of the resulting protein or to the regulation of gene expression. The most common type of RNA editing in mammals is the hydrolytic deamination of adenosine (A) to inosine (I), catalyzed by a family of enzymes called adenosine deaminases acting on RNA (ADARs). Inosine is recognized as guanosine (G) by the translation machinery, leading to A-to-G changes in the RNA sequence. Other types of RNA editing include cytidine (C) to uridine (U) deamination and insertion/deletion of nucleotides. RNA editing is a crucial mechanism for generating diversity in gene expression and has been implicated in various biological processes, including development, differentiation, and disease.

I'm sorry for any confusion, but "Virus Physiological Phenomena" is not a widely recognized or established medical term or concept. It seems to be a combination of two concepts: "virus" and "physiological phenomena."

1. A virus is a small infectious agent that replicates inside the living cells of an organism. Viruses can cause many different types of illnesses, from the common cold to more serious diseases like HIV/AIDS or hepatitis.

2. Physiological phenomena refer to the functions and activities of living organisms and their parts, including cells, tissues, and organs.

If you're looking for information about how viruses affect physiological processes in the body, I would be happy to help provide some general information on that topic! However, it would be best to consult a specific medical text or expert for more detailed or specialized knowledge.

RNA stability refers to the duration that a ribonucleic acid (RNA) molecule remains intact and functional within a cell before it is degraded or broken down into its component nucleotides. Various factors can influence RNA stability, including:

1. Primary sequence: Certain sequences in the RNA molecule may be more susceptible to degradation by ribonucleases (RNases), enzymes that break down RNA.
2. Secondary structure: The formation of stable secondary structures, such as hairpins or stem-loop structures, can protect RNA from degradation.
3. Presence of RNA-binding proteins: Proteins that bind to RNA can either stabilize or destabilize the RNA molecule, depending on the type and location of the protein-RNA interaction.
4. Chemical modifications: Modifications to the RNA nucleotides, such as methylation, can increase RNA stability by preventing degradation.
5. Subcellular localization: The subcellular location of an RNA molecule can affect its stability, with some locations providing more protection from ribonucleases than others.
6. Cellular conditions: Changes in cellular conditions, such as pH or temperature, can also impact RNA stability.

Understanding RNA stability is important for understanding gene regulation and the function of non-coding RNAs, as well as for developing RNA-based therapeutic strategies.

Post-transcriptional RNA processing refers to the modifications and regulations that occur on RNA molecules after the transcription of DNA into RNA. This process includes several steps:

1. 5' capping: The addition of a cap structure, usually a methylated guanosine triphosphate (GTP), to the 5' end of the RNA molecule. This helps protect the RNA from degradation and plays a role in its transport, stability, and translation.
2. 3' polyadenylation: The addition of a string of adenosine residues (poly(A) tail) to the 3' end of the RNA molecule. This process is important for mRNA stability, export from the nucleus, and translation initiation.
3. Intron removal and exon ligation: Eukaryotic pre-messenger RNAs (pre-mRNAs) contain intronic sequences that do not code for proteins. These introns are removed by a process called splicing, where the flanking exons are joined together to form a continuous mRNA sequence. Alternative splicing can lead to different mature mRNAs from a single pre-mRNA, increasing transcriptomic and proteomic diversity.
4. RNA editing: Specific nucleotide changes in RNA molecules that alter the coding potential or regulatory functions of RNA. This process is catalyzed by enzymes like ADAR (Adenosine Deaminases Acting on RNA) and APOBEC (Apolipoprotein B mRNA Editing Catalytic Polypeptide-like).
5. Chemical modifications: Various chemical modifications can occur on RNA nucleotides, such as methylation, pseudouridination, and isomerization. These modifications can influence RNA stability, localization, and interaction with proteins or other RNAs.
6. Transport and localization: Mature mRNAs are transported from the nucleus to the cytoplasm for translation. In some cases, specific mRNAs are localized to particular cellular compartments to ensure local protein synthesis.
7. Degradation: RNA molecules have finite lifetimes and undergo degradation by various ribonucleases (RNases). The rate of degradation can be influenced by factors such as RNA structure, modifications, or interactions with proteins.

DNAB helicases are a type of enzyme that are essential for DNA replication. They function by unwinding the double-stranded DNA molecule into two single strands, creating a replication fork. This allows other enzymes to access the DNA and synthesize new strands. The "DNAB" designation refers to the fact that these helicases were first discovered in bacteria, although similar enzymes are found in all organisms.

DNAB helicases are large protein complexes that consist of several subunits. They use the energy from ATP hydrolysis to power the unwinding of the DNA helix. The unwound single strands of DNA are then coated with single-stranded binding proteins to prevent them from reannealing.

DNAB helicases play a critical role in initiating and maintaining the progression of the replication fork during DNA replication. Defects in DNAB helicases can lead to genomic instability and increased mutation rates, which can contribute to the development of cancer and other diseases.

Nucleic acid conformation refers to the three-dimensional structure that nucleic acids (DNA and RNA) adopt as a result of the bonding patterns between the atoms within the molecule. The primary structure of nucleic acids is determined by the sequence of nucleotides, while the conformation is influenced by factors such as the sugar-phosphate backbone, base stacking, and hydrogen bonding.

Two common conformations of DNA are the B-form and the A-form. The B-form is a right-handed helix with a diameter of about 20 Å and a pitch of 34 Å, while the A-form has a smaller diameter (about 18 Å) and a shorter pitch (about 25 Å). RNA typically adopts an A-form conformation.

The conformation of nucleic acids can have significant implications for their function, as it can affect their ability to interact with other molecules such as proteins or drugs. Understanding the conformational properties of nucleic acids is therefore an important area of research in molecular biology and medicine.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Ribosomes are complex macromolecular structures composed of ribonucleic acid (RNA) and proteins that play a crucial role in protein synthesis within cells. They serve as the site for translation, where messenger RNA (mRNA) is translated into a specific sequence of amino acids to create a polypeptide chain, which eventually folds into a functional protein.

Ribosomes consist of two subunits: a smaller subunit and a larger subunit. These subunits are composed of ribosomal RNA (rRNA) molecules and proteins. In eukaryotic cells, the smaller subunit is denoted as the 40S subunit, while the larger subunit is referred to as the 60S subunit. In prokaryotic cells, these subunits are named the 30S and 50S subunits, respectively. The ribosome's overall structure resembles a "doughnut" or a "cotton reel," with grooves and binding sites for various factors involved in protein synthesis.

Ribosomes can be found floating freely within the cytoplasm of cells or attached to the endoplasmic reticulum (ER) membrane, forming part of the rough ER. Membrane-bound ribosomes are responsible for synthesizing proteins that will be transported across the ER and ultimately secreted from the cell or inserted into the membrane. In contrast, cytoplasmic ribosomes synthesize proteins destined for use within the cytoplasm or organelles.

In summary, ribosomes are essential components of cells that facilitate protein synthesis by translating mRNA into functional polypeptide chains. They can be found in various cellular locations and exist as either free-floating entities or membrane-bound structures.

Amino acid motifs are recurring patterns or sequences of amino acids in a protein molecule. These motifs can be identified through various sequence analysis techniques and often have functional or structural significance. They can be as short as two amino acids in length, but typically contain at least three to five residues.

Some common examples of amino acid motifs include:

1. Active site motifs: These are specific sequences of amino acids that form the active site of an enzyme and participate in catalyzing chemical reactions. For example, the catalytic triad in serine proteases consists of three residues (serine, histidine, and aspartate) that work together to hydrolyze peptide bonds.
2. Signal peptide motifs: These are sequences of amino acids that target proteins for secretion or localization to specific organelles within the cell. For example, a typical signal peptide consists of a positively charged n-region, a hydrophobic h-region, and a polar c-region that directs the protein to the endoplasmic reticulum membrane for translocation.
3. Zinc finger motifs: These are structural domains that contain conserved sequences of amino acids that bind zinc ions and play important roles in DNA recognition and regulation of gene expression.
4. Transmembrane motifs: These are sequences of hydrophobic amino acids that span the lipid bilayer of cell membranes and anchor transmembrane proteins in place.
5. Phosphorylation sites: These are specific serine, threonine, or tyrosine residues that can be phosphorylated by protein kinases to regulate protein function.

Understanding amino acid motifs is important for predicting protein structure and function, as well as for identifying potential drug targets in disease-associated proteins.

RNA-binding proteins (RBPs) are a class of proteins that selectively interact with RNA molecules to form ribonucleoprotein complexes. These proteins play crucial roles in the post-transcriptional regulation of gene expression, including pre-mRNA processing, mRNA stability, transport, localization, and translation. RBPs recognize specific RNA sequences or structures through their modular RNA-binding domains, which can be highly degenerate and allow for the recognition of a wide range of RNA targets. The interaction between RBPs and RNA is often dynamic and can be regulated by various post-translational modifications of the proteins or by environmental stimuli, allowing for fine-tuning of gene expression in response to changing cellular needs. Dysregulation of RBP function has been implicated in various human diseases, including neurological disorders and cancer.

Bacterial RNA refers to the genetic material present in bacteria that is composed of ribonucleic acid (RNA). Unlike higher organisms, bacteria contain a single circular chromosome made up of DNA, along with smaller circular pieces of DNA called plasmids. These bacterial genetic materials contain the information necessary for the growth and reproduction of the organism.

Bacterial RNA can be divided into three main categories: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). mRNA carries genetic information copied from DNA, which is then translated into proteins by the rRNA and tRNA molecules. rRNA is a structural component of the ribosome, where protein synthesis occurs, while tRNA acts as an adapter that brings amino acids to the ribosome during protein synthesis.

Bacterial RNA plays a crucial role in various cellular processes, including gene expression, protein synthesis, and regulation of metabolic pathways. Understanding the structure and function of bacterial RNA is essential for developing new antibiotics and other therapeutic strategies to combat bacterial infections.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Bloom syndrome is a rare genetic disorder characterized by short stature, sun-sensitive skin rash, and an increased risk of developing cancer. It is caused by mutations in the BLM gene, which provides instructions for making a protein that helps prevent tangles and knots from forming in DNA during cell division. As a result, cells with Bloom syndrome have a high rate of genetic recombination, leading to chromosomal instability and an increased risk of cancer.

Individuals with Bloom syndrome typically have a distinctive facial appearance, including a narrow face, small jaw, and a prominent nose. They may also have learning disabilities, fertility problems, and an increased susceptibility to infections. The condition is inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to develop the disorder. Bloom syndrome is typically diagnosed through genetic testing and chromosome analysis. Treatment is focused on managing the symptoms and reducing the risk of cancer through regular screenings and lifestyle modifications.

Saccharomyces cerevisiae proteins are the proteins that are produced by the budding yeast, Saccharomyces cerevisiae. This organism is a single-celled eukaryote that has been widely used as a model organism in scientific research for many years due to its relatively simple genetic makeup and its similarity to higher eukaryotic cells.

The genome of Saccharomyces cerevisiae has been fully sequenced, and it is estimated to contain approximately 6,000 genes that encode proteins. These proteins play a wide variety of roles in the cell, including catalyzing metabolic reactions, regulating gene expression, maintaining the structure of the cell, and responding to environmental stimuli.

Many Saccharomyces cerevisiae proteins have human homologs and are involved in similar biological processes, making this organism a valuable tool for studying human disease. For example, many of the proteins involved in DNA replication, repair, and recombination in yeast have human counterparts that are associated with cancer and other diseases. By studying these proteins in yeast, researchers can gain insights into their function and regulation in humans, which may lead to new treatments for disease.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

RNA viruses are a type of virus that contain ribonucleic acid (RNA) as their genetic material, as opposed to deoxyribonucleic acid (DNA). RNA viruses replicate by using an enzyme called RNA-dependent RNA polymerase to transcribe and replicate their RNA genome.

There are several different groups of RNA viruses, including:

1. Negative-sense single-stranded RNA viruses: These viruses have a genome that is complementary to the mRNA and must undergo transcription to produce mRNA before translation can occur. Examples include influenza virus, measles virus, and rabies virus.
2. Positive-sense single-stranded RNA viruses: These viruses have a genome that can serve as mRNA and can be directly translated into protein after entry into the host cell. Examples include poliovirus, rhinoviruses, and coronaviruses.
3. Double-stranded RNA viruses: These viruses have a genome consisting of double-stranded RNA and use a complex replication strategy involving both transcription and reverse transcription. Examples include rotaviruses and reoviruses.

RNA viruses are known to cause a wide range of human diseases, ranging from the common cold to more severe illnesses such as hepatitis C, polio, and COVID-19. Due to their high mutation rates and ability to adapt quickly to new environments, RNA viruses can be difficult to control and treat with antiviral drugs or vaccines.

DNA-directed RNA polymerases are enzymes that synthesize RNA molecules using a DNA template in a process called transcription. These enzymes read the sequence of nucleotides in a DNA molecule and use it as a blueprint to construct a complementary RNA strand.

The RNA polymerase moves along the DNA template, adding ribonucleotides one by one to the growing RNA chain. The synthesis is directional, starting at the promoter region of the DNA and moving towards the terminator region.

In bacteria, there is a single type of RNA polymerase that is responsible for transcribing all types of RNA (mRNA, tRNA, and rRNA). In eukaryotic cells, however, there are three different types of RNA polymerases: RNA polymerase I, II, and III. Each type is responsible for transcribing specific types of RNA.

RNA polymerases play a crucial role in gene expression, as they link the genetic information encoded in DNA to the production of functional proteins. Inhibition or mutation of these enzymes can have significant consequences for cellular function and survival.

RNA interference (RNAi) is a biological process in which RNA molecules inhibit the expression of specific genes. This process is mediated by small RNA molecules, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), that bind to complementary sequences on messenger RNA (mRNA) molecules, leading to their degradation or translation inhibition.

RNAi plays a crucial role in regulating gene expression and defending against foreign genetic elements, such as viruses and transposons. It has also emerged as an important tool for studying gene function and developing therapeutic strategies for various diseases, including cancer and viral infections.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Werner Syndrome is a rare, autosomal recessive genetic disorder characterized by the appearance of premature aging. It's often referred to as "progeria of the adult" or "adult progeria." The syndrome is caused by mutations in the WRN gene, which provides instructions for making a protein involved in repairing damaged DNA and maintaining the stability of the genetic information.

The symptoms typically begin in a person's late teens or early twenties and may include:
- Short stature
- Premature graying and loss of hair
- Skin changes, such as scleroderma (a thickening and hardening of the skin) and ulcers
- Voice changes
- Type 2 diabetes
- Cataracts
- Atherosclerosis (the buildup of fats, cholesterol, and other substances in and on the artery walls)
- Increased risk of cancer

The life expectancy of individuals with Werner Syndrome is typically around 45 to 50 years. It's important to note that while there are similarities between Werner Syndrome and other forms of progeria, such as Hutchinson-Gilford Progeria Syndrome, they are distinct conditions with different genetic causes and clinical features.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

A conserved sequence in the context of molecular biology refers to a pattern of nucleotides (in DNA or RNA) or amino acids (in proteins) that has remained relatively unchanged over evolutionary time. These sequences are often functionally important and are highly conserved across different species, indicating strong selection pressure against changes in these regions.

In the case of protein-coding genes, the corresponding amino acid sequence is deduced from the DNA sequence through the genetic code. Conserved sequences in proteins may indicate structurally or functionally important regions, such as active sites or binding sites, that are critical for the protein's activity. Similarly, conserved non-coding sequences in DNA may represent regulatory elements that control gene expression.

Identifying conserved sequences can be useful for inferring evolutionary relationships between species and for predicting the function of unknown genes or proteins.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

HeLa cells are a type of immortalized cell line used in scientific research. They are derived from a cancer that developed in the cervical tissue of Henrietta Lacks, an African-American woman, in 1951. After her death, cells taken from her tumor were found to be capable of continuous division and growth in a laboratory setting, making them an invaluable resource for medical research.

HeLa cells have been used in a wide range of scientific studies, including research on cancer, viruses, genetics, and drug development. They were the first human cell line to be successfully cloned and are able to grow rapidly in culture, doubling their population every 20-24 hours. This has made them an essential tool for many areas of biomedical research.

It is important to note that while HeLa cells have been instrumental in numerous scientific breakthroughs, the story of their origin raises ethical questions about informed consent and the use of human tissue in research.

"Cold temperature" is a relative term and its definition can vary depending on the context. In general, it refers to temperatures that are lower than those normally experienced or preferred by humans and other warm-blooded animals. In a medical context, cold temperature is often defined as an environmental temperature that is below 16°C (60.8°F).

Exposure to cold temperatures can have various physiological effects on the human body, such as vasoconstriction of blood vessels near the skin surface, increased heart rate and metabolic rate, and shivering, which helps to generate heat and maintain body temperature. Prolonged exposure to extreme cold temperatures can lead to hypothermia, a potentially life-threatening condition characterized by a drop in core body temperature below 35°C (95°F).

It's worth noting that some people may have different sensitivities to cold temperatures due to factors such as age, health status, and certain medical conditions. For example, older adults, young children, and individuals with circulatory or neurological disorders may be more susceptible to the effects of cold temperatures.

Ribonucleoproteins (RNPs) are complexes composed of ribonucleic acid (RNA) and proteins. They play crucial roles in various cellular processes, including gene expression, RNA processing, transport, stability, and degradation. Different types of RNPs exist, such as ribosomes, spliceosomes, and signal recognition particles, each having specific functions in the cell.

Ribosomes are large RNP complexes responsible for protein synthesis, where messenger RNA (mRNA) is translated into proteins. They consist of two subunits: a smaller subunit containing ribosomal RNA (rRNA) and proteins that recognize the start codon on mRNA, and a larger subunit with rRNA and proteins that facilitate peptide bond formation during translation.

Spliceosomes are dynamic RNP complexes involved in pre-messenger RNA (pre-mRNA) splicing, where introns (non-coding sequences) are removed, and exons (coding sequences) are joined together to form mature mRNA. Spliceosomes consist of five small nuclear ribonucleoproteins (snRNPs), each containing a specific small nuclear RNA (snRNA) and several proteins, as well as numerous additional proteins.

Other RNP complexes include signal recognition particles (SRPs), which are responsible for targeting secretory and membrane proteins to the endoplasmic reticulum during translation, and telomerase, an enzyme that maintains the length of telomeres (the protective ends of chromosomes) by adding repetitive DNA sequences using its built-in RNA component.

In summary, ribonucleoproteins are essential complexes in the cell that participate in various aspects of RNA metabolism and protein synthesis.

Hydrolysis is a chemical process, not a medical one. However, it is relevant to medicine and biology.

Hydrolysis is the breakdown of a chemical compound due to its reaction with water, often resulting in the formation of two or more simpler compounds. In the context of physiology and medicine, hydrolysis is a crucial process in various biological reactions, such as the digestion of food molecules like proteins, carbohydrates, and fats. Enzymes called hydrolases catalyze these hydrolysis reactions to speed up the breakdown process in the body.

RNA Polymerase II is a type of enzyme responsible for transcribing DNA into RNA in eukaryotic cells. It plays a crucial role in the process of gene expression, where the information stored in DNA is used to create proteins. Specifically, RNA Polymerase II transcribes protein-coding genes to produce precursor messenger RNA (pre-mRNA), which is then processed into mature mRNA. This mature mRNA serves as a template for protein synthesis during translation.

RNA Polymerase II has a complex structure, consisting of multiple subunits, and it requires the assistance of various transcription factors and coactivators to initiate and regulate transcription. The enzyme recognizes specific promoter sequences in DNA, unwinds the double-stranded DNA, and synthesizes a complementary RNA strand using one of the unwound DNA strands as a template. This process results in the formation of a nascent RNA molecule that is further processed into mature mRNA for protein synthesis or other functional RNAs involved in gene regulation.

Protein biosynthesis is the process by which cells generate new proteins. It involves two major steps: transcription and translation. Transcription is the process of creating a complementary RNA copy of a sequence of DNA. This RNA copy, or messenger RNA (mRNA), carries the genetic information to the site of protein synthesis, the ribosome. During translation, the mRNA is read by transfer RNA (tRNA) molecules, which bring specific amino acids to the ribosome based on the sequence of nucleotides in the mRNA. The ribosome then links these amino acids together in the correct order to form a polypeptide chain, which may then fold into a functional protein. Protein biosynthesis is essential for the growth and maintenance of all living organisms.

Virus replication is the process by which a virus produces copies or reproduces itself inside a host cell. This involves several steps:

1. Attachment: The virus attaches to a specific receptor on the surface of the host cell.
2. Penetration: The viral genetic material enters the host cell, either by invagination of the cell membrane or endocytosis.
3. Uncoating: The viral genetic material is released from its protective coat (capsid) inside the host cell.
4. Replication: The viral genetic material uses the host cell's machinery to produce new viral components, such as proteins and nucleic acids.
5. Assembly: The newly synthesized viral components are assembled into new virus particles.
6. Release: The newly formed viruses are released from the host cell, often through lysis (breaking) of the cell membrane or by budding off the cell membrane.

The specific mechanisms and details of virus replication can vary depending on the type of virus. Some viruses, such as DNA viruses, use the host cell's DNA polymerase to replicate their genetic material, while others, such as RNA viruses, use their own RNA-dependent RNA polymerase or reverse transcriptase enzymes. Understanding the process of virus replication is important for developing antiviral therapies and vaccines.

A catalytic RNA, often referred to as a ribozyme, is a type of RNA molecule that has the ability to act as an enzyme and catalyze chemical reactions. These RNA molecules contain specific sequences and structures that allow them to bind to other molecules and accelerate chemical reactions without being consumed in the process.

Ribozymes play important roles in various biological processes, such as RNA splicing, translation regulation, and gene expression. One of the most well-known ribozymes is the self-splicing intron found in certain RNA molecules, which can excise itself from the host RNA and then ligase the flanking exons together.

The discovery of catalytic RNAs challenged the central dogma of molecular biology, which held that proteins were solely responsible for carrying out biological catalysis. The finding that RNA could also function as an enzyme opened up new avenues of research and expanded our understanding of the complexity and versatility of biological systems.

RNA folding, also known as RNA structure formation or RNA tertiary structure prediction, refers to the process by which an RNA molecule folds into a specific three-dimensional shape based on its primary sequence. This shape is determined by intramolecular interactions between nucleotides within the RNA chain, including base pairing (through hydrogen bonding) and stacking interactions. The folded structure of RNA plays a crucial role in its function, as it can create specific binding sites for proteins or other molecules, facilitate or inhibit enzymatic activity, or influence the stability and localization of the RNA within the cell.

RNA folding is a complex process that can be influenced by various factors such as temperature, ionic conditions, and molecular crowding. The folded structure of an RNA molecule can be predicted using computational methods, such as thermodynamic modeling and machine learning algorithms, which take into account the primary sequence and known patterns of base pairing and stacking interactions to generate a model of the three-dimensional structure. However, experimental techniques, such as chemical probing and crystallography, are often necessary to validate and refine these predictions.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Exodeoxyribonucleases are a type of enzyme that cleave (break) nucleotides from the ends of DNA molecules. They are further classified into 5' exodeoxyribonucleases and 3' exodeoxyribonucleases based on the end of the DNA molecule they act upon.

5' Exodeoxyribonucleases remove nucleotides from the 5' end (phosphate group) of a DNA strand, while 3' exodeoxyribonucleases remove nucleotides from the 3' end (hydroxyl group) of a DNA strand.

These enzymes play important roles in various biological processes such as DNA replication, repair, and degradation. They are also used in molecular biology research for various applications such as DNA sequencing, cloning, and genetic engineering.

DNA replication is the biological process by which DNA makes an identical copy of itself during cell division. It is a fundamental mechanism that allows genetic information to be passed down from one generation of cells to the next. During DNA replication, each strand of the double helix serves as a template for the synthesis of a new complementary strand. This results in the creation of two identical DNA molecules. The enzymes responsible for DNA replication include helicase, which unwinds the double helix, and polymerase, which adds nucleotides to the growing strands.

Deoxyribonucleic acid (DNA) is the genetic material present in the cells of organisms where it is responsible for the storage and transmission of hereditary information. DNA is a long molecule that consists of two strands coiled together to form a double helix. Each strand is made up of a series of four nucleotide bases - adenine (A), guanine (G), cytosine (C), and thymine (T) - that are linked together by phosphate and sugar groups. The sequence of these bases along the length of the molecule encodes genetic information, with A always pairing with T and C always pairing with G. This base-pairing allows for the replication and transcription of DNA, which are essential processes in the functioning and reproduction of all living organisms.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

The cell nucleus is a membrane-bound organelle found in the eukaryotic cells (cells with a true nucleus). It contains most of the cell's genetic material, organized as DNA molecules in complex with proteins, RNA molecules, and histones to form chromosomes.

The primary function of the cell nucleus is to regulate and control the activities of the cell, including growth, metabolism, protein synthesis, and reproduction. It also plays a crucial role in the process of mitosis (cell division) by separating and protecting the genetic material during this process. The nuclear membrane, or nuclear envelope, surrounding the nucleus is composed of two lipid bilayers with numerous pores that allow for the selective transport of molecules between the nucleoplasm (nucleus interior) and the cytoplasm (cell exterior).

The cell nucleus is a vital structure in eukaryotic cells, and its dysfunction can lead to various diseases, including cancer and genetic disorders.

Rothmund-Thomson syndrome (RTS) is a rare genetic disorder characterized by the triad of poikiloderma, juvenile cataracts, and skeletal abnormalities. Poikiloderma is a skin condition that involves changes in coloration, including redness, brownish pigmentation, and telangiectasia (dilation of small blood vessels), as well as atrophy (wasting) of the skin.

The syndrome is caused by mutations in the RECQL4 gene, which plays a role in DNA repair. RTS has an autosomal recessive pattern of inheritance, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to develop the condition.

Individuals with RTS may also experience other symptoms, such as sparse hair, short stature, small hands and feet, missing teeth, and a predisposition to developing certain types of cancer, particularly osteosarcoma (a type of bone cancer). The severity of the condition can vary widely among individuals.

RTS is typically diagnosed based on clinical features and genetic testing. Treatment is focused on managing the symptoms of the condition and may include measures such as sun protection to prevent skin damage, eye exams to monitor for cataracts, and regular cancer screenings.

Fungal genes refer to the genetic material present in fungi, which are eukaryotic organisms that include microorganisms such as yeasts and molds, as well as larger organisms like mushrooms. The genetic material of fungi is composed of DNA, just like in other eukaryotes, and is organized into chromosomes located in the nucleus of the cell.

Fungal genes are segments of DNA that contain the information necessary to produce proteins and RNA molecules required for various cellular functions. These genes are transcribed into messenger RNA (mRNA) molecules, which are then translated into proteins by ribosomes in the cytoplasm.

Fungal genomes have been sequenced for many species, revealing a diverse range of genes that encode proteins involved in various cellular processes such as metabolism, signaling, and regulation. Comparative genomic analyses have also provided insights into the evolutionary relationships among different fungal lineages and have helped to identify unique genetic features that distinguish fungi from other eukaryotes.

Understanding fungal genes and their functions is essential for advancing our knowledge of fungal biology, as well as for developing new strategies to control fungal pathogens that can cause diseases in humans, animals, and plants.

Antisense RNA is a type of RNA molecule that is complementary to another RNA called sense RNA. In the context of gene expression, sense RNA is the RNA transcribed from a protein-coding gene, which serves as a template for translation into a protein. Antisense RNA, on the other hand, is transcribed from the opposite strand of the DNA and is complementary to the sense RNA.

Antisense RNA can bind to its complementary sense RNA through base-pairing, forming a double-stranded RNA structure. This interaction can prevent the sense RNA from being translated into protein or can target it for degradation by cellular machinery, thereby reducing the amount of protein produced from the gene. Antisense RNA can be used as a tool in molecular biology to study gene function or as a therapeutic strategy to silence disease-causing genes.

Single-stranded DNA (ssDNA) is a form of DNA that consists of a single polynucleotide chain. In contrast, double-stranded DNA (dsDNA) consists of two complementary polynucleotide chains that are held together by hydrogen bonds.

In the double-helix structure of dsDNA, each nucleotide base on one strand pairs with a specific base on the other strand through hydrogen bonding: adenine (A) with thymine (T), and guanine (G) with cytosine (C). This base pairing provides stability to the double-stranded structure.

Single-stranded DNA, on the other hand, lacks this complementary base pairing and is therefore less stable than dsDNA. However, ssDNA can still form secondary structures through intrastrand base pairing, such as hairpin loops or cruciform structures.

Single-stranded DNA is found in various biological contexts, including viral genomes, transcription bubbles during gene expression, and in certain types of genetic recombination. It also plays a critical role in some laboratory techniques, such as polymerase chain reaction (PCR) and DNA sequencing.

A multigene family is a group of genetically related genes that share a common ancestry and have similar sequences or structures. These genes are arranged in clusters on a chromosome and often encode proteins with similar functions. They can arise through various mechanisms, including gene duplication, recombination, and transposition. Multigene families play crucial roles in many biological processes, such as development, immunity, and metabolism. Examples of multigene families include the globin genes involved in oxygen transport, the immune system's major histocompatibility complex (MHC) genes, and the cytochrome P450 genes associated with drug metabolism.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

Transfer RNA (tRNA) is a type of RNA molecule that plays a crucial role in protein synthesis, the process by which cells create proteins. In protein synthesis, tRNAs serve as adaptors, translating the genetic code present in messenger RNA (mRNA) into the corresponding amino acids required to build a protein.

Each tRNA molecule has a distinct structure, consisting of approximately 70-90 nucleotides arranged in a cloverleaf shape with several loops and stems. The most important feature of a tRNA is its anticodon, a sequence of three nucleotides located in one of the loops. This anticodon base-pairs with a complementary codon on the mRNA during translation, ensuring that the correct amino acid is added to the growing polypeptide chain.

Before tRNAs can participate in protein synthesis, they must be charged with their specific amino acids through an enzymatic process involving aminoacyl-tRNA synthetases. These enzymes recognize and bind to both the tRNA and its corresponding amino acid, forming a covalent bond between them. Once charged, the aminoacyl-tRNA complex is ready to engage in translation and contribute to protein formation.

In summary, transfer RNA (tRNA) is a small RNA molecule that facilitates protein synthesis by translating genetic information from messenger RNA into specific amino acids, ultimately leading to the creation of functional proteins within cells.

Nuclear proteins are a category of proteins that are primarily found in the nucleus of a eukaryotic cell. They play crucial roles in various nuclear functions, such as DNA replication, transcription, repair, and RNA processing. This group includes structural proteins like lamins, which form the nuclear lamina, and regulatory proteins, such as histones and transcription factors, that are involved in gene expression. Nuclear localization signals (NLS) often help target these proteins to the nucleus by interacting with importin proteins during active transport across the nuclear membrane.

Small nuclear RNA (snRNA) are a type of RNA molecules that are typically around 100-300 nucleotides in length. They are found within the nucleus of eukaryotic cells and are components of small nuclear ribonucleoproteins (snRNPs), which play important roles in various aspects of RNA processing, including splicing of pre-messenger RNA (pre-mRNA) and regulation of transcription.

There are several classes of snRNAs, each with a distinct function. The most well-studied class is the spliceosomal snRNAs, which include U1, U2, U4, U5, and U6 snRNAs. These snRNAs form complexes with proteins to form small nuclear ribonucleoprotein particles (snRNPs) that recognize specific sequences in pre-mRNA and catalyze the removal of introns during splicing.

Other classes of snRNAs include signal recognition particle (SRP) RNA, which is involved in targeting proteins to the endoplasmic reticulum, and Ro60 RNA, which is associated with autoimmune diseases such as systemic lupus erythematosus.

Overall, small nuclear RNAs are essential components of the cellular machinery that regulates gene expression and protein synthesis in eukaryotic cells.

Innate immunity, also known as non-specific immunity or natural immunity, is the inherent defense mechanism that provides immediate protection against potentially harmful pathogens (like bacteria, viruses, fungi, and parasites) without the need for prior exposure. This type of immunity is present from birth and does not adapt to specific threats over time.

Innate immune responses involve various mechanisms such as:

1. Physical barriers: Skin and mucous membranes prevent pathogens from entering the body.
2. Chemical barriers: Enzymes, stomach acid, and lysozyme in tears, saliva, and sweat help to destroy or inhibit the growth of microorganisms.
3. Cellular responses: Phagocytic cells (neutrophils, monocytes, macrophages) recognize and engulf foreign particles and pathogens, while natural killer (NK) cells target and eliminate virus-infected or cancerous cells.
4. Inflammatory response: When an infection occurs, the innate immune system triggers inflammation to increase blood flow, recruit immune cells, and remove damaged tissue.
5. Complement system: A group of proteins that work together to recognize and destroy pathogens directly or enhance phagocytosis by coating them with complement components (opsonization).

Innate immunity plays a crucial role in initiating the adaptive immune response, which is specific to particular pathogens and provides long-term protection through memory cells. Both innate and adaptive immunity work together to maintain overall immune homeostasis and protect the body from infections and diseases.

Untranslated regions (UTRs) of RNA are the non-coding sequences that are present in mRNA (messenger RNA) molecules, which are located at both the 5' end (5' UTR) and the 3' end (3' UTR) of the mRNA, outside of the coding sequence (CDS). These regions do not get translated into proteins. They contain regulatory elements that play a role in the regulation of gene expression by affecting the stability, localization, and translation efficiency of the mRNA molecule. The 5' UTR typically contains the Shine-Dalgarno sequence in prokaryotes or the Kozak consensus sequence in eukaryotes, which are important for the initiation of translation. The 3' UTR often contains regulatory elements such as AU-rich elements (AREs) and microRNA (miRNA) binding sites that can affect mRNA stability and translation.

Fungal proteins are a type of protein that is specifically produced and present in fungi, which are a group of eukaryotic organisms that include microorganisms such as yeasts and molds. These proteins play various roles in the growth, development, and survival of fungi. They can be involved in the structure and function of fungal cells, metabolism, pathogenesis, and other cellular processes. Some fungal proteins can also have important implications for human health, both in terms of their potential use as therapeutic targets and as allergens or toxins that can cause disease.

Fungal proteins can be classified into different categories based on their functions, such as enzymes, structural proteins, signaling proteins, and toxins. Enzymes are proteins that catalyze chemical reactions in fungal cells, while structural proteins provide support and protection for the cell. Signaling proteins are involved in communication between cells and regulation of various cellular processes, and toxins are proteins that can cause harm to other organisms, including humans.

Understanding the structure and function of fungal proteins is important for developing new treatments for fungal infections, as well as for understanding the basic biology of fungi. Research on fungal proteins has led to the development of several antifungal drugs that target specific fungal enzymes or other proteins, providing effective treatment options for a range of fungal diseases. Additionally, further study of fungal proteins may reveal new targets for drug development and help improve our ability to diagnose and treat fungal infections.

RNA caps are structures found at the 5' end of RNA molecules, including messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). These caps consist of a modified guanine nucleotide (called 7-methylguanosine) that is linked to the first nucleotide of the RNA chain through a triphosphate bridge. The RNA cap plays several important roles in regulating RNA metabolism, including protecting the RNA from degradation by exonucleases, promoting the recognition and binding of the RNA by ribosomes during translation, and modulating the stability and transport of the RNA within the cell.

Nucleoside-triphosphatase (NTPase) is not a medical term per se, but rather a biochemical term. However, it is often used in the context of molecular biology and genetics, which are essential components of medical research and practice. Therefore, I will provide a definition related to these fields.

Nucleoside-triphosphatase (NTPase) refers to an enzyme that catalyzes the hydrolysis of nucleoside triphosphates (NTPs) into nucleoside diphosphates (NDPs) and inorganic phosphate (Pi). NTPs, such as adenosine triphosphate (ATP), guanosine triphosphate (GTP), cytidine triphosphate (CTP), and uridine triphosphate (UTP), are crucial for energy transfer in cells.

In the context of molecular biology, NTPases play essential roles in various cellular processes, including DNA replication, transcription, translation, and degradation. For example, DNA polymerase, an enzyme involved in DNA replication, is a type of NTPase that utilizes dNTPs (deoxynucleoside triphosphates) to synthesize new DNA strands. Similarly, RNA polymerase, which catalyzes the transcription of DNA into RNA, uses NTPs as substrates and has NTPase activity.

In summary, Nucleoside-triphosphatase (NTPase) is an enzyme that hydrolyzes nucleoside triphosphates (NTPs), releasing energy and playing a critical role in various cellular processes, including DNA replication, transcription, translation, and degradation.

RNA Sequence Analysis is a branch of bioinformatics that involves the determination and analysis of the nucleotide sequence of Ribonucleic Acid (RNA) molecules. This process includes identifying and characterizing the individual RNA molecules, determining their functions, and studying their evolutionary relationships.

RNA Sequence Analysis typically involves the use of high-throughput sequencing technologies to generate large datasets of RNA sequences, which are then analyzed using computational methods. The analysis may include comparing the sequences to reference databases to identify known RNA molecules or discovering new ones, identifying patterns and features in the sequences, such as motifs or domains, and predicting the secondary and tertiary structures of the RNA molecules.

RNA Sequence Analysis has many applications in basic research, including understanding gene regulation, identifying novel non-coding RNAs, and studying evolutionary relationships between organisms. It also has practical applications in clinical settings, such as diagnosing and monitoring diseases, developing new therapies, and personalized medicine.

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

Ribonucleic acid (RNA) in plants refers to the long, single-stranded molecules that are essential for the translation of genetic information from deoxyribonucleic acid (DNA) into proteins. RNA is a nucleic acid, like DNA, and it is composed of a ribose sugar backbone with attached nitrogenous bases (adenine, uracil, guanine, and cytosine).

In plants, there are several types of RNA that play specific roles in the gene expression process:

1. Messenger RNA (mRNA): This type of RNA carries genetic information copied from DNA in the form of a sequence of three-base code units called codons. These codons specify the order of amino acids in a protein.
2. Transfer RNA (tRNA): tRNAs are small RNA molecules that serve as adaptors between the mRNA and the amino acids during protein synthesis. Each tRNA has a specific anticodon sequence that base-pairs with a complementary codon on the mRNA, and it carries a specific amino acid that corresponds to that codon.
3. Ribosomal RNA (rRNA): rRNAs are structural components of ribosomes, which are large macromolecular complexes where protein synthesis occurs. In plants, there are several types of rRNAs, including the 18S, 5.8S, and 25S/28S rRNAs, that form the core of the ribosome and help catalyze peptide bond formation during protein synthesis.
4. Small nuclear RNA (snRNA): These are small RNA molecules that play a role in RNA processing, such as splicing, where introns (non-coding sequences) are removed from pre-mRNA and exons (coding sequences) are joined together to form mature mRNAs.
5. MicroRNA (miRNA): These are small non-coding RNAs that regulate gene expression by binding to complementary sequences in target mRNAs, leading to their degradation or translation inhibition.

Overall, these different types of RNAs play crucial roles in various aspects of RNA metabolism, gene regulation, and protein synthesis in plants.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

I'd be happy to help! However, I believe there might be a slight confusion in your question. RNA stands for Ribonucleic Acid, which is a type of nucleic acid involved in various biological roles in the coding, decoding, regulation, and expression of genes. On the other hand, protozoan refers to a unicellular organism from the kingdom Protista, which includes a wide variety of simple eukaryotic organisms such as amoebas, paramecia, and plasmodium (the malaria-causing parasite).

There isn't a specific medical definition for "RNA, protozoan" since RNA is a molecule present in all living cells, including human cells, and protozoans are a group of organisms. However, I can tell you that RNA plays crucial roles in protozoan biology, such as acting as a messenger between DNA and ribosomes during protein synthesis or regulating gene expression.

If you have any further questions or need more specific information about RNA in protozoans, please let me know!

Genomic instability is a term used in genetics and molecular biology to describe a state of increased susceptibility to genetic changes or mutations in the genome. It can be defined as a condition where the integrity and stability of the genome are compromised, leading to an increased rate of DNA alterations such as point mutations, insertions, deletions, and chromosomal rearrangements.

Genomic instability is a hallmark of cancer cells and can also be observed in various other diseases, including genetic disorders and aging. It can arise due to defects in the DNA repair mechanisms, telomere maintenance, epigenetic regulation, or chromosome segregation during cell division. These defects can result from inherited genetic mutations, acquired somatic mutations, exposure to environmental mutagens, or age-related degenerative changes.

Genomic instability is a significant factor in the development and progression of cancer as it promotes the accumulation of oncogenic mutations that contribute to tumor initiation, growth, and metastasis. Therefore, understanding the mechanisms underlying genomic instability is crucial for developing effective strategies for cancer prevention, diagnosis, and treatment.

DNA repair is the process by which cells identify and correct damage to the DNA molecules that encode their genome. DNA can be damaged by a variety of internal and external factors, such as radiation, chemicals, and metabolic byproducts. If left unrepaired, this damage can lead to mutations, which may in turn lead to cancer and other diseases.

There are several different mechanisms for repairing DNA damage, including:

1. Base excision repair (BER): This process repairs damage to a single base in the DNA molecule. An enzyme called a glycosylase removes the damaged base, leaving a gap that is then filled in by other enzymes.
2. Nucleotide excision repair (NER): This process repairs more severe damage, such as bulky adducts or crosslinks between the two strands of the DNA molecule. An enzyme cuts out a section of the damaged DNA, and the gap is then filled in by other enzymes.
3. Mismatch repair (MMR): This process repairs errors that occur during DNA replication, such as mismatched bases or small insertions or deletions. Specialized enzymes recognize the error and remove a section of the newly synthesized strand, which is then replaced by new nucleotides.
4. Double-strand break repair (DSBR): This process repairs breaks in both strands of the DNA molecule. There are two main pathways for DSBR: non-homologous end joining (NHEJ) and homologous recombination (HR). NHEJ directly rejoins the broken ends, while HR uses a template from a sister chromatid to repair the break.

Overall, DNA repair is a crucial process that helps maintain genome stability and prevent the development of diseases caused by genetic mutations.

RNA (Ribonucleic acid) is a single-stranded molecule similar in structure to DNA, involved in the process of protein synthesis in the cell. It acts as a messenger carrying genetic information from DNA to the ribosomes, where proteins are produced.

A neoplasm, on the other hand, is an abnormal growth of cells, which can be benign or malignant. Benign neoplasms are not cancerous and do not invade nearby tissues or spread to other parts of the body. Malignant neoplasms, however, are cancerous and have the potential to invade surrounding tissues and spread to distant sites in the body through a process called metastasis.

Therefore, an 'RNA neoplasm' is not a recognized medical term as RNA is not a type of growth or tumor. However, there are certain types of cancer-causing viruses known as oncoviruses that contain RNA as their genetic material and can cause neoplasms. For example, human T-cell leukemia virus (HTLV-1) and hepatitis C virus (HCV) are RNA viruses that can cause certain types of cancer in humans.

RNA transport refers to the process by which messenger RNA (mRNA) molecules are transferred from the nucleus to the cytoplasm in eukaryotic cells. After being transcribed in the nucleus, mRNA molecules must be transported to the cytoplasm where they can be translated into proteins on ribosomes. This process is essential for gene expression and involves a complex network of proteins and RNA-binding factors that facilitate the recognition, packaging, and transport of mRNA through the nuclear pore complex.

The transport of mRNA is a highly regulated process that ensures the proper localization and translation of specific mRNAs in response to various cellular signals. Abnormalities in RNA transport have been implicated in several neurological disorders, including amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA).

Premature aging, also known as "accelerated aging" or "early aging," refers to the physiological process in which the body shows signs of aging at an earlier age than typically expected. This can include various symptoms such as wrinkles, graying hair, decreased energy and mobility, cognitive decline, and increased risk of chronic diseases.

The medical definition of premature aging is not well-established, as aging is a complex process influenced by a variety of genetic and environmental factors. However, certain conditions and syndromes are associated with premature aging, such as Hutchinson-Gilford progeria syndrome, Werner syndrome, and Down syndrome.

In general, the signs of premature aging may be caused by a combination of genetic predisposition, lifestyle factors (such as smoking, alcohol consumption, and poor diet), exposure to environmental toxins, and chronic stress. While some aspects of aging are inevitable, maintaining a healthy lifestyle and reducing exposure to harmful factors can help slow down the aging process and improve overall quality of life.

The RNA helicase database stores data (sequence, structures...) about RNA helicases. Helicase Jankowsky, Anja; Guenther Ulf- ... www.rnahelicase.org v t e (Biological databases, RNA, RNA-binding proteins, All stub articles, Biological database stubs). ... "The RNA helicase database". Nucleic Acids Res. England. 39 (Database issue): D338-41. doi:10.1093/nar/gkq1002. PMC 3013637. ...
The RNA-binding domains and RGG box influence and regulate RNA helicase activity. The DHX9 gene is located on the long arm q of ... DEAD/DEAH box helicases are proteins, and are putative RNA helicases. They are implicated in a number of cellular processes ... This gene encodes a DEAD box protein with RNA helicase activity. It may participate in melting of DNA:RNA hybrids, such as ... Zhang S, Grosse F (Apr 1997). "Domain structure of human nuclear DNA helicase II (RNA helicase A)". The Journal of Biological ...
The ssNA-helicase RNA motif is a conserved RNA structure that was discovered by bioinformatics. Although the ssNA-helicase ... The ssNA-helicase motif occurs upstream of genes that likely function as helicases, possible on an RNA substrate. Some evidence ... ssNA-helicase motif RNAs are found in Bacillota and Actinomycetota. ... If the RNA is indeed part of a phage, then its location upstream of a protein-coding gene might just reflect the typical gene ...
Vasa is an RNA binding protein with an ATP-dependent RNA helicase that is a member of the DEAD box family of proteins. The vasa ... The Vasa gene is a member of the DEAD box family of RNA helicases in Drosophila melanogaster. Its human ortholog, Ddx4, is ... Linder P, Lasko P (April 2006). "Bent out of shape: RNA unwinding by the DEAD-box helicase Vasa". Cell. 125 (2): 219-21. doi: ... It uses ATP dependent RNA helicase catalytic activity to regulate the translation of multiple mRNAs. Vasa unwinds the duplex ...
2002). "The human La (SS-B) autoantigen interacts with DDX15/hPrp43, a putative DEAH-box RNA helicase". RNA. 8 (11): 1428-43. ... Putative pre-mRNA-splicing factor ATP-dependent RNA helicase DHX15 is an enzyme that in humans is encoded by the DHX15 gene. ... The protein encoded by this gene is a putative ATP-dependent RNA helicase implicated in pre-mRNA splicing. It may have tumor ... "Entrez Gene: DHX15 DEAH (Asp-Glu-Ala-His) box polypeptide 15". Ito S, Koso H, Sakamoto K (Oct 2017). "RNA helicase DHX15 acts ...
RNA binding and RNA helicase activity, based on catalysis of the reaction that unwinds an RNA helix: ATP + H2O = ADP + ... A wide range of RNA helicases belongs to this family. Specifically, DHX8 acts as an ATP-dependent RNA helicase involved in ... DHX8 have different domains: a S1 RNA binding domain (DEAD/DEAH box), an helicase conserved C-terminal domain, helicase ... "Structural and functional characterisation of human RNA helicase DHX8 provides insights into the mechanism of RNA-stimulated ...
These paralogs operate under a SPF1 RNA helicase motif. Mov10, a paralog, and probable RNA helicase is required for RNA- ... A majority of these proteins are in the RNA helicase family. There are no known paralogs to the large N-terminal portion of the ... Jankowsky E (Jan 2011). "RNA helicases at work: binding and rearranging". Trends in Biochemical Sciences. 36 (1): 19-29. doi: ... with small capped HDV RNAs derived from genomic hairpin structures that mark the initiation sites of RNA-dependent HDV RNA ...
... is a member of the DEAD box family of RNA helicases. RNA helicases are enzymes that use the energy released from the ... other DEAD-box RNA helicases have been shown to possess helicase activity in the presence of nonhydrolyzable analogues of ATP, ... It is the most prevalent member of the eIF4A family of ATP-dependant RNA helicases, and plays a critical role in the initiation ... eIF4A1 is an ATP-dependent RNA helicase, however the exact nature of its dependence on ATP for its function is still debated. ...
All remodelers fall under the umbrella of RNA/DNA helicase superfamily 2. In yeast, CHD complexes are primarily responsible for ... Chromodomain helicase DNA-binding (CHD) proteins is a subfamily of ATP-dependent chromatin remodeling complexes (remodelers). ... Mills, Alea A. (April 2017). "The Chromodomain Helicase DNA-Binding Chromatin Remodelers: Family Traits that Protect from and ...
Chen HC, Lin WC, Tsay YG, Lee SC, Chang CJ (October 2002). "An RNA helicase, DDX1, interacting with poly(A) RNA and ... are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary ... "An RNA helicase, DDX1, interacting with poly(A) RNA and heterogeneous nuclear ribonucleoprotein K" (PDF). The Journal of ... ATP-dependent RNA helicase DDX1 is an enzyme that in humans is encoded by the DDX1 gene. DEAD box proteins, characterized by ...
The hyp codifies for an RNA-helicase; mutants for this gene are hypervirulent. Also, hyp is involved in post transcriptional ...
Milner-White, EJ; Pietras Z; Luisi BF (2010). "An ancient anion-binding structural module in RNA and DNA helicases". Proteins. ... occur as ST motifs and form part of the characteristic nucleotide binding sites of SF1 and SF2 type DNA and RNA helicases. It ...
... (RNA Helicase associated with AU-rich element, also known as DHX36 or G4R1) is a 114-kDa human RNA helicase of the DEAH- ... "Recruitment of the RNA helicase RHAU to stress granules via a unique RNA-binding domain". The Journal of Biological Chemistry. ... "Characterizing functional domains of the RNA helicase RHAU involved in subcellular localization and RNA interaction" (PDF).[ ... Abdelhaleem M, Maltais L, Wain H (June 2003). "The human DDX and DHX gene families of putative RNA helicases". Genomics. 81 (6 ...
"Recruitment of the RNA helicase RHAU to stress granules via a unique RNA-binding domain". The Journal of Biological Chemistry. ... Like all the DEAH/RHA helicases, the helicase associated domain is located adjacent to the helicase core region and occupies 75 ... "Characterizing functional domains of the RNA helicase RHAU involved in subcellular localization and RNA interaction" (PDF).[ ... Probable ATP-dependent RNA helicase DHX36 also known as DEAH box protein 36 (DHX36) or MLE-like protein 1 (MLEL1) or G4 ...
... are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary ... Abdelhaleem M, Maltais L, Wain H (2004). "The human DDX and DHX gene families of putative RNA helicases". Genomics. 81 (6): 618 ...
Caruthers JM, Johnson ER, McKay DB (Nov 2000). "Crystal structure of yeast initiation factor 4A, a DEAD-box RNA helicase". ... Pause A, Sonenberg N (Jul 1992). "Mutational analysis of a DEAD box RNA helicase: the mammalian translation initiation factor ... In addition these proteins are helicases that function to unwind double-stranded RNA. The mechanisms governing the basic ... Lin D, Pestova TV, Hellen CU, Tiedge H (May 2008). "Translational control by a small RNA: dendritic BC1 RNA targets the ...
Brennan CA, Dombroski AJ, Platt T (March 1987). "Transcription termination factor rho is an RNA-DNA helicase". Cell. 48 (6): ... causing the dissociation of the RNA polymerase from the template and the release of the new RNA strand. In RNA polymerase II, ... In RNA polymerase I, Transcription termination factor, RNA polymerase I binds downstream of the pre-rRNA coding regions, ... When the Rho protein reaches the RNA polymerase complex, transcription is terminated by dissociation of the RNA polymerase from ...
... are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary ... Probable ATP-dependent RNA helicase DDX17 (p72) is an enzyme that in humans is encoded by the DDX17 gene. DEAD box proteins, ... Wilson BJ, Bates GJ, Nicol SM, Gregory DJ, Perkins ND, Fuller-Pace FV (Aug 2004). "The p68 and p72 DEAD box RNA helicases ... Wilson BJ, Bates GJ, Nicol SM, Gregory DJ, Perkins ND, Fuller-Pace FV (2005). "The p68 and p72 DEAD box RNA helicases interact ...
This folding is catalyzed by endo- and exonucleases, RNA helicases, GTPases and ATPases. The rRNA subsequently undergoes endo- ... Ribosomal RNA is the predominant form of RNA found in most cells; it makes up about 80% of cellular RNA despite never being ... This requires the presence of all three RNA polymerases. In fact, the transcription of pre-RNA by RNA polymerase I accounts for ... Zemora G, Waldsich C (November 2010). "RNA folding in living cells". RNA Biology. 7 (6): 634-41. doi:10.4161/rna.7.6.13554. PMC ...
Smith WA, Schurter BT, Wong-Staal F, David M (May 2004). "Arginine methylation of RNA helicase a determines its subcellular ... Côté J, Boisvert FM, Boulanger MC, Bedford MT, Richard S (January 2003). "Sam68 RNA binding protein is an in vivo substrate for ... "The Arginine-1493 Residue in QRRGRTGR1493G Motif IV of the Hepatitis C Virus NS3 Helicase Domain Is Essential for NS3 Protein ... "Methylation of SPT5 regulates its interaction with RNA polymerase II and transcriptional elongation properties". Mol. Cell. 11 ...
Sugiura T, Sakurai K, Nagano Y (2007). "Intracellular characterization of DDX39, a novel growth-associated RNA helicase". Exp. ...
The senataxin protein, which has RNA-DNA helicase activity, and DHX9 human helicase can resolve R-loops. This allows XRN2, an ... Sen1 in yeast is a RNA/DNA helicase and the highly conserved sequences between these genes, particularly in the helicase domain ... Senataxin interacts with RNA polymerase II and poly(A) binding proteins. At the C-terminal, senataxin has a DEAD box helicase ... June 2004). "DNA/RNA helicase gene mutations in a form of juvenile amyotrophic lateral sclerosis (ALS4)". American Journal of ...
These include regions with protease, helicase and RNA polymerase motifs. There are seven other genes downstream which encode ... The genome is positive-sense, single-stranded RNA with a length of 27 to 29 kilobases and a 3'-polyA tail. Two large, ... They are positive-sense, single-stranded RNA viruses that infect mammals, including humans. They have spherical virions with ... Feline coronavirus Human CCoV-HuPn-2018 Porcine transmissible gastroenteritis coronavirus Betacoronavirus Coronavirus RNA virus ...
It interacts at all times with FRH (FRQ-interacting RNA helicase; an essential DEAD box-containing RNA helicase in Neurospora) ... Cheng P, He Q, He Q, Wang L, Liu Y (January 2005). "Regulation of the Neurospora circadian clock by an RNA helicase". Genes & ... Shi M, Collett M, Loros JJ, Dunlap JC (2010). "FRQ-interacting RNA helicase mediates negative and positive feedback in the ... Hurley JM, Larrondo LF, Loros JJ, Dunlap JC (December 2013). "Conserved RNA helicase FRH acts nonenzymatically to support the ...
Further, stress granules contain many RNA helicases, including the DEAD/H-box helicases Ded1p/DDX3, eIF4A1, and RHAU. In yeast ... RNA phase transitions driven in part by intermolecular RNA-RNA interactions may play a role in stress granule formation. ... There is also evidence that RNA within stress granules is more compacted, compared to RNA in the cytoplasm, and that the RNA is ... Thus, some hypothesize that RNA aggregation facilitated by intermolecular RNA-RNA interactions plays a role in stress granule ...
... and are putative RNA helicases. They are implicated in a number of cellular processes involving alteration of RNA secondary ... ATP-dependent RNA helicase DDX39 is an enzyme that in humans is encoded by the DDX39 gene. This gene encodes a member of the ... Aug 1995). "The BAT1 gene in the MHC encodes an evolutionarily conserved putative nuclear RNA helicase of the DEAD family". ... Sugiura T, Sakurai K, Nagano Y (2007). "Intracellular characterization of DDX39, a novel growth-associated RNA helicase". Exp. ...
Gomez De Cedrón, M.; Ehsani, N.; Mikkola, M. L.; García, J. A.; Kääriäinen, L. (1999). "RNA helicase activity of Semliki Forest ... Replication occurs via a negative strand intermediate giving rise to a full length genomic RNA for export in new virions and a ... The Semliki Forest virus is a positive-strand RNA virus with a genome of approximately 13,000 base pairs which encodes nine ... The 5' two thirds of the genome encode four non-structural proteins concerned with RNA synthesis; the structural proteins are ...
"Cloning and Characterization of DEAD-box RNA Helicases Gene from the Fern Equisetum arvense". Plant Diversity and Resources. 36 ...
"Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses". Nature. 441 (7089): 101-105. Bibcode: ... He has helped to define the cells and pathways involved in innate immune detection of RNA viruses, fungi and dead cells. Reis e ... "Innate Antiviral Responses by Means of TLR7-Mediated Recognition of Single-Stranded RNA". Science. 303 (5663): 1529-1531. ... "RIG-I-Mediated Antiviral Responses to Single-Stranded RNA Bearing 5'-Phosphates". Science. 314 (5801): 997-1001. Bibcode: ...
Also, sequential mutations of the RNA helicases (involved in RNA synthesis) DDX3X (found on the x chromosome) and DDX3Y (found ... "Sequential inverse dysregulation of the RNA helicases DDX3X and DDX3Y facilitates MYC-driven lymphomagenesis". Molecular Cell. ... and DDX3Y mutations are thought to partially explain why Burkitt lymphoma is more common in males as the DDX3Y RNA helicase is ...
The RNA helicase database stores data (sequence, structures...) about RNA helicases. Helicase Jankowsky, Anja; Guenther Ulf- ... www.rnahelicase.org v t e (Biological databases, RNA, RNA-binding proteins, All stub articles, Biological database stubs). ... "The RNA helicase database". Nucleic Acids Res. England. 39 (Database issue): D338-41. doi:10.1093/nar/gkq1002. PMC 3013637. ...
RNA helicase activity of Mtr4p is critical for biological functions of the enzyme, but the molecular basis for RNA unwinding is ... The conserved Saccharomyces cerevisiae Ski2-like RNA helicase Mtr4p plays essential roles in eukaryotic nuclear RNA processing ... We further show that RNA unwinding by Mtr4p requires interaction with upstream RNA duplex. Inclusion of Mtr4p within the TRAMP ... optical trapping techniques elucidate the molecular mechanisms underlying the unwinding of RNA duplexes by the helicase Mtr4p, ...
Protein target information for RNA helicase (chicken). Find diseases associated with this biological target and compounds ...
... Nat Genet. 2004 Mar;36(3):225-7. doi: ... Ten of the fifteen mutations cause premature termination of a large DEAxQ-box helicase, the human ortholog of yeast Sen1p, ...
Structure of the RNA Helicase MLE Reveals the Molecular Mechanisms for Uridine Specificity and RNA-ATP Coupling ... MLEcore is an unusual DExH helicase that can unwind blunt-ended RNA duplexes and has specificity for uridine nucleotides. We ... The MLE helicase remodels the roX lncRNAs, enabling the lncRNA-mediated assembly of the Drosophila dosage compensation complex ... We identified a stable MLE core comprising the DExH helicase module and two auxiliary domains: a dsRBD and an OB-like fold. ...
To investigate the ability of the conditional mtr4 mutants in processing various RNAs, we used chemiluminescent northern ... Mtr4 is an essential RNA helicase associated with the nuclear exosome and aids in the processing and degradation of many RNAs. ... blotting to demonstrate one conditional mutants defects in RNA processing and degradation. In order to probe for additional ... Mtr4 is an essential RNA helicase associated with the nuclear exosome and aids in the processing and degradation of many RNAs. ...
All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family ... All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family ... All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family ... All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family ...
DEAH-box RNA-dependent ATPase/ATP-dependent RNA he... [more]. PRP43. 2.387e-154. 40.85. RNA helicase in the DEAH-box family; ... ATP-dependent RNA helicase DHX8 OS=Araneus ventric... [more]. A0A091E849. 2.401e-177. 44.16. ATP-dependent RNA helicase DHX8 ( ... ATP-dependent RNA helicase DHX8 (Fragment) OS=Gavi... [more]. A0A093PX93. 2.401e-177. 44.16. ATP-dependent RNA helicase DHX8 ( ... ATP-DEPENDENT RNA HELICASE. coord: 34..644. None. No IPR available. PANTHER. PTHR18934:SF85. ATP-DEPENDENT RNA HELICASE DHX8. ...
... including RNA-dependent ATPase and RNA helicase- function in all organisms to sculpt RNA-RNA duplex and RNA-protein complexes, ... Identified as a prototypic member of the DEAD box family and documented as an ATPase and RNA helicase, p68 plays essential and ... The dissertation thus demonstrates a tight coordination between DEAD box RNA helicase and cancer development. ... including RNA-dependent ATPase and RNA helicase- function in all organisms to sculpt RNA-RNA duplex and RNA-protein complexes, ...
RNA polymerase II has an unexpected function in the nucleolus, helping to drive the expression of ribosomal RNA and to protect ... Here we show, however, that RNA polymerase II (Pol II) inside human nucleoli operates near genes encoding rRNAs to drive their ... Our findings revise theories of labour division between the major RNA polymerases, and identify nucleolar Pol II as a major ... The shield prevents Pol I from producing sense intergenic noncoding RNAs (sincRNAs) that can disrupt nucleolar organization and ...
However, RNA viruses with shorter than 6 kB genomes usually do not code for RNA helicases. They could still use RNA helicases ... Thus, two small RNA viruses, which do not code for their own helicases, seems to recruit a host RNA helicase to aid their ... Thus, two small RNA viruses, which do not code for their own helicases, seems to recruit a host RNA helicase to aid their ... Since Ded1p is an RNA helicase [39], [41] and the ATPase/helicase function of Ded1p is needed for stimulation of (+)RNA ...
Ago Hook and RNA Helicase Motifs Underpin Dual Roles for SDE3 in Antiviral Defense and Silencing of Nonconserved Intergenic ...
probable ATP-dependent RNA helicase DDX60. Names. ATP-dependent RNA helicase DDX60. DEAD (Asp-Glu-Ala-Asp) box polypeptide 60. ... are putative RNA helicases which are implicated in a number of cellular procsses involving RNA binding and alteration of RNA ... Dob10; Superfamily II RNA helicase [Replication, recombination and repair]. * XM_024454133.2 → XP_024309901.1 probable ATP- ... Dob10; Superfamily II RNA helicase [Replication, recombination and repair]. * XM_011532104.4 → XP_011530406.1 probable ATP- ...
The hRPC62 subunit of human RNA polymerase III displays helicase activity. ... Abstract: In Eukaryotes, tRNAs, 5S RNA and U6 RNA are transcribed by RNA polymerase (Pol) III. Human Pol III is composed of 17 ... The hRPC62 subunit of human RNA polymerase III displays helicase activity. Ayoubi, L. E., Dumay-Odelot, H., Chernev, A., ... 2019). The hRPC62 subunit of human RNA polymerase III displays helicase activity. Nucleic Acids Research, 47(19), 10313-10326. ...
The product Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA) is intended to be used for ... The product Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA) should be kept between two and ... Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA). ... Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA) ...
Expression of the cyanobacterial DEAD-box RNA helicase, crhR, is regulated in response to conditions, which elicit reduction of ... Expression of the cyanobacterial DEAD-box RNA helicase, crhR, is regulated in response to conditions, which elicit reduction of ... A LexA-related protein regulates redox-sensitive expression of the cyanobacterial RNA helicase, crhR. ... A LexA-related protein regulates redox-sensitive expression of the cyanobacterial RNA helicase, crhR. Nucleic Acids Research, ...
RNA Helicases / immunology* * RNA Helicases / metabolism * Reactive Oxygen Species / immunology * Reactive Oxygen Species / ...
An RNAi Screen of RNA Helicases Identifies eIF4A3 as a Regulator of Embryonic Stem Cell Identity. *Jianlong Wang ... An RNAi Screen of RNA Helicases Identifies eIF4A3 as a Regulator of Embryonic Stem Cell Identity. ...
Protein export cytoplasm protein SecA ATPase RNA helicase (TC 3.A.5.1.1) CDS 2066457 2068883 + 2 427 808 FALSE ... Rv1821 Protein export cytoplasm protein SecA ATPase RNA helicase (TC 3.A.5.1.1). Genome Browser ... Rv1821 (Protein export cytoplasm protein SecA ATPase RNA helicase (TC 3.A.5.1.1)) is predicted to be co-regulated in modules ... These modules are enriched for following go terms: oxidoreductase activity, acting on a sul..., helicase activity, ...
SKIV2L: Ski2 like RNA helicase. *SLC1A3: solute carrier family 1 member 3 ...
The Human RNA Helicase DDX21 Presents a Dimerization Interface Necessary for Helicase Activity. M. J. Marcaida Lopez; A. ... Characterization of APOBEC3G binding to 7SL RNA. D. Bach; S. Peddy; B. Mangeat; A. Lakkaraju; K. Strub et al. ... Efficient and sensitive profiling of RNA-protein interactions using TLC-CLIP. C. Ernst; J. Duc; D. Trono ... KAP1 targets actively transcribed genomic loci to exert pleomorphic effects on RNA polymerase II activity. A. Kauzlaric; S. M. ...
Human nuclear exosome-MTR4 RNA complex - composite map after focused reconstruction ... The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3 to 5 Mtr4 helicase ... Helicase-Dependent RNA Decay Illuminated by a Cryo-EM Structure of a Human Nuclear RNA Exosome-MTR4 Complex.. Weick, E.M., Puno ... Exosome RNA helicase MTR4. M. 1,045. Homo sapiens. Mutation(s): 0 Gene Names: MTREX, DOB1, KIAA0052, MTR4, SKIV2L2. EC: 3.6. ...
keywords = "ATP-dependent RNA helicases, DEAD-box proteins, Helicase C domain, Protozoan proteins, Trypanosoma brucei, ZC3H41", ... ATP-dependent RNA helicase domain of the ZC3H41 protein from Trypanosoma brucei: Expression, purification and crystallization. ... Izhaki-Tavor, L. S., & Dessau, M. (2020). ATP-dependent RNA helicase domain of the ZC3H41 protein from Trypanosoma brucei: ... ATP-dependent RNA helicase domain of the ZC3H41 protein from Trypanosoma brucei: Expression, purification and crystallization. ...
eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and Is Modulated by Phosphorylation ... eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylation ... eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylation ... eIF4A RNA Helicase Associates with Cyclin-Dependent Protein Kinase A in Proliferating Cells and is Modulated by Phosphorylation ...
RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. However, the functional ... In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF- ... significance of RNA helicases in aging has not been explored. Here, we report that a large fraction of RNA helicases regulate ... RNA helicase HEL-1 promotes longevity by specifically activating DAF-1… 첨부파일 *첨부된 파일이 없습니다. ...
A DEAD box RNA helicase is essential for mRNA export and important for development and stress responses in Arabidopsis. In: ... A DEAD box RNA helicase is essential for mRNA export and important for development and stress responses in Arabidopsis. Plant ... A DEAD box RNA helicase is essential for mRNA export and important for development and stress responses in Arabidopsis. / Gong ... Gong, Z., Dong, C. H., Lee, H., Zhu, J., Xiong, L., Gong, D., Stevenson, B., & Zhu, J. K. (2005). A DEAD box RNA helicase is ...
The HCMV helicase-primase complex (pUL105-pUL102-pUL70) is essential for viral DNA replication and could thus be a relevant ... The HCMV helicase-primase complex (pUL105-pUL102-pUL70) is essential for viral DNA replication and could thus be a relevant ... Promising new inhibitors that target the viral helicase-primase complex have been reported to block replication of herpes ... Promising new inhibitors that target the viral helicase-primase complex have been reported to block replication of herpes ...
ATP-dependent RNA helicase, nuclear core complex protein. FANCN/PALB2, 1% of mutations ... The gene product is DNA helicase RecQ--like 3, one of 5 members of the RecQ helicase family. The normal protein functions as a ... Knockout chicken for FANCJ/BRIP1/BACH1 revealed that the gene product is a DEAH helicase that interacts with BRCA1. ... XPB and XPD are also involved in regulation of the basal rate of RNA synthesis of active genes. ...
  • The dissertation thus demonstrates a tight coordination between DEAD box RNA helicase and cancer development. (gsu.edu)
  • A Co-Opted DEAD-Box RNA Helicase Enhances Tomb. (prolekarniky.cz)
  • In this paper, we show that an essential translation factor, Ded1p DEAD-box RNA helicase of yeast, directly affects replication of Tomato bushy stunt virus (TBSV). (prolekarniky.cz)
  • Subsite-specific association of DEAD box RNA helicase DDX60 with the development and prognosis of oral squamous cell carcinoma. (nih.gov)
  • Expression of the cyanobacterial DEAD-box RNA helicase, crhR, is regulated in response to conditions, which elicit reduction of the photosynthetic electron transport chain. (macewan.ca)
  • In particular, we show that a DEAD-box RNA helicase, helicase 1 (HEL-1), promotes longevity by specifically activating the DAF-16/forkhead box O (FOXO) transcription factor signaling pathway. (postech.ac.kr)
  • The mutation was found in a DEAD box RNA helicase gene that is identical to the previously identified low expression of osmotically responsive genes 4 (LOS4) locus, which was defined by the los4-1 mutation that reduces cold regulation of CBFs and their target genes and renders Arabidopsis plants chilling sensitive. (edu.sa)
  • DEAD-box RNA helicases. (embl.de)
  • DExD/H-box RNA helicases are motor proteins participating in nearly all aspects of cellular processes, especially in RNA metabolism. (syr.edu)
  • Activities of the DEAD box (Asp-Glu-Ala-Asp) family of proteins- including RNA-dependent ATPase and RNA helicase- function in all organisms to sculpt RNA-RNA duplex and RNA-protein complexes, ensuring that necessary rearrangements are rapidly and properly resolved during genetic information processing. (gsu.edu)
  • Altogether, the two host factors enhance TBSV replication synergistically by interacting with the viral (−)RNA and the replication proteins. (prolekarniky.cz)
  • After translation of their mRNA-sense genomic RNA(s), the viral RNA and the viral replication proteins are recruited to the site of viral replication in membranous compartments. (prolekarniky.cz)
  • For efficient replication, (+)RNA viruses recruit numerous host proteins [1] - [5] . (prolekarniky.cz)
  • Among the identified host proteins are RNA-binding proteins, such as translation factors, ribosomal proteins and RNA-modifying enzymes [1] . (prolekarniky.cz)
  • The co-opted host proteins likely affect several steps in viral RNA replication, including the assembly of the replicase complex and/or viral RNA synthesis. (prolekarniky.cz)
  • The single genomic RNA codes for two replication proteins, p33 and p92 pol , which are sufficient to support TBSV replicon (rep)RNA replication in yeast ( Saccharomyces cerevisiae ) model host [13] , [14] . (prolekarniky.cz)
  • DEAD box proteins, characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD), are putative RNA helicases which are implicated in a number of cellular procsses involving RNA binding and alteration of RNA secondary structure. (nih.gov)
  • 2023). Defining RNA oligonucleotides that reverse deleterious phase transitions of RNA-binding proteins with prion-like domains. (upenn.edu)
  • Long-term memory consolidation: The role of RNA-binding proteins with prion-like domains. (tcd.ie)
  • Wang, X., Jia, H., Jankowsky, E. & Anderson, J.T. Degradation of hypomodified tRNA(iMet) in vivo involves RNA-dependent ATPase activity of the DExH helicase Mtr4p. (nature.com)
  • Identified as a prototypic member of the DEAD box family and documented as an ATPase and RNA helicase, p68 plays essential and diverse functions in the control of gene expression ranging from pre-mRNA/rRNA processing and mRNA decay/stability to transcriptional activation and initiation. (gsu.edu)
  • The data obtained with wt and ATPase deficient Ded1p mutants support the model that Ded1p unwinds local structures at the 3′-end of the TBSV (−)RNA, rendering the RNA compatible for initiation of (+)-strand synthesis. (prolekarniky.cz)
  • eIF4A is a highly conserved RNA-stimulated ATPase and helicase involved in the initiation of mRNA translation. (aber.ac.uk)
  • The N-terminal domain also contains motif III (S-A-T) which was proposed to participate in linking ATPase and helicase activities. (embl.de)
  • A new yeast poly(A) polymerase complex involved in RNA quality control. (nature.com)
  • Here we show, however, that RNA polymerase II (Pol II) inside human nucleoli operates near genes encoding rRNAs to drive their expression. (nature.com)
  • The hRPC62 subunit of human RNA polymerase III displays helicase activity. (mpg.de)
  • In Eukaryotes, tRNAs, 5S RNA and U6 RNA are transcribed by RNA polymerase (Pol) III. (mpg.de)
  • cystein protease, helicase, and RNA polymerase. (cdc.gov)
  • RNA-directed RNA polymerase. (cathdb.info)
  • TATA-box binding protein is not required for RNA Polymerase II transcription in mouse embryonic stem cells. (elifesciences.org)
  • An ATP-dependent 3'-5' DNA helicase which is a component of the core-TFIIH basal transcription factor, involved in nucleotide excision repair (NER) of DNA and, when complexed to CAK, in RNA transcription by RNA polymerase II. (embl.de)
  • 2022). Sexually dimorphic RNA helicases DDX3X and DDX3Y differentially regulate RNA metabolism through phase separation. (upenn.edu)
  • Our findings revise theories of labour division between the major RNA polymerases, and identify nucleolar Pol II as a major factor in protein synthesis and nuclear organization, with potential implications for health and disease. (nature.com)
  • A fragment of the Trypanosoma brucei ZC3H41 protein encompassing the ATP-dependent RNA helicase domain was successfully subcloned for expression in a bacterial system (Escherichia coli). (iucc.ac.il)
  • Izhaki-Tavor, LS & Dessau, M 2020, ' ATP-dependent RNA helicase domain of the ZC3H41 protein from Trypanosoma brucei: Expression, purification and crystallization ', Acta Crystallographica Section F:Structural Biology Communications , vol. 76, pp. 604-608. (iucc.ac.il)
  • RNA-protein multiome approach helps to discover that the posttranscriptional regulation of the translational machinery is crucial for the fidelity of cortical development. (elifesciences.org)
  • Altered Ribostasis: RNA-Protein Granules in Degenerative Disorders. (tcd.ie)
  • The conserved Saccharomyces cerevisiae Ski2-like RNA helicase Mtr4p plays essential roles in eukaryotic nuclear RNA processing. (nature.com)
  • Johnson, S.J. & Jackson, R.N. Ski2-like RNA helicase structures: common themes and complex assemblies. (nature.com)
  • The structure visualizes a transition-state mimic of the reaction and suggests how eukaryotic DEAH/RHA helicases couple ATP hydrolysis to RNA translocation. (cipsm.de)
  • All eukaryotic plus-stranded (+)RNA viruses have similar replication cycles in infected cells. (prolekarniky.cz)
  • Eukaryotic DNA repair helicase RAD3/ERCC-2, an ATP-dependent 5'-3' DNA helicase involved in nucleotide excision repair of UV-damaged DNA. (embl.de)
  • Eukaryotic TFIIH basal transcription factor complex helicase XPB subunit. (embl.de)
  • Eukaryotic ATP-dependent DNA helicase Q. A DNA helicase that may play a role in the repair of DNA that is damaged by ultraviolet light or other mutagens. (embl.de)
  • Bacterial and eukaryotic antiviral SKI2-like helicase. (embl.de)
  • de la Cruz, J., Kressler, D., Tollervey, D. & Linder, P. Dob1p (Mtr4p) is a putative ATP-dependent RNA helicase required for the 3′ end formation of 5.8S rRNA in Saccharomyces cerevisiae . (nature.com)
  • Additional putative genotypes have been identifi ed through analysis of an 130-nt fragment of the To explore the genetic diversity of avian hepatitis E virus helicase domain, suggesting that diversity within aHEV is strains, we characterized the near-complete genome of a higher than recognized ( 11 ). (cdc.gov)
  • Sloan, K.E., Bohnsack, M.T., Schneider, C. & Watkins, N.J. The roles of SSU processome components and surveillance factors in the initial processing of human ribosomal RNA. (nature.com)
  • Existing models suggest that RNA polymerases I and III (Pol I and Pol III) are the only enzymes that directly mediate the expression of the ribosomal RNA (rRNA) components of ribosomes. (nature.com)
  • All the catfish RNA helicases contained conserved helicase signature motifs, demonstrating that the RNA helicase gene family was highly conserved. (syr.edu)
  • This gene encodes a DEXD/H box RNA helicase that functions as an antiviral factor and promotes RIG-I-like receptor-mediated signaling. (nih.gov)
  • Glomerular endothelial expression of type I IFN-stimulated gene, DExD/H-Box helicase 60 via toll-like receptor 3 signaling: possible involvement in the pathogenesis of lupus nephritis. (nih.gov)
  • Figure 2: Mtr4p unwinding rates versus tether tension and nucleotide composition for unwinding the 16-bp RNA hairpin. (nature.com)
  • Catalyzes RNA-template-directed extension of the 3'-end of an RNA strand by one nucleotide at a time. (cathdb.info)
  • In vitro, wild type recombinant eIF4A1 and its phospho-null variant both support translation in cell free wheat germ extracts dependent upon eIF4A, but the phosphomimetic variant does not support translation and was also deficient in ATP hydrolysis and helicase activity. (aber.ac.uk)
  • DNA helicases utilize the energy from ATP hydrolysis to unwind double-stranded DNA. (cathdb.info)
  • In this study, a total of 54 DExD/H-box RNA helicase genes including 37 DDX (DEAD-box) and 17 DHX (DEAH-box) genes were characterized in channel catfish (Ictalurus punctatus), and annotated through phylogenetic and syntenic analyses. (syr.edu)
  • DEAH-box RNA helicases. (embl.de)
  • RNA degradation by the exosome is promoted by a nuclear polyadenylation complex. (nature.com)
  • Callahan, K.P. & Butler, J.S. TRAMP complex enhances RNA degradation by the nuclear exosome component Rrp6. (nature.com)
  • Mtr4 is an essential RNA helicase associated with the nuclear exosome and aids in the processing and degradation of many RNAs. (richmond.edu)
  • To investigate the ability of the conditional mtr4 mutants in processing various RNAs, we used chemiluminescent northern blotting to demonstrate one conditional mutant's defects in RNA processing and degradation. (richmond.edu)
  • To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4-containing RNA exosomes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and human and show that they unwind structured substrates to promote degradation. (rcsb.org)
  • Competition for the exosome core may ensure that RNA is committed to degradation by DIS3 when engaged by MTR4. (rcsb.org)
  • RNA helicases are a large family of enzymes that regulate the biogenesis and homeostasis of RNA. (postech.ac.kr)
  • Here, we report that a large fraction of RNA helicases regulate the lifespan of Caenorhabditis elegans. (postech.ac.kr)
  • MicroRNAs (miRNAs) and other classes of short non-coding RNAs regulate essential processes in the development and function of the nervous system. (harvard.edu)
  • Bernstein, J., Patterson, D.N., Wilson, G.M. & Toth, E.A. Characterization of the essential activities of Saccharomyces cerevisiae Mtr4p, a 3′>5′ helicase partner of the nuclear exosome. (nature.com)
  • We identified a stable MLE core comprising the DExH helicase module and two auxiliary domains: a dsRBD and an OB-like fold. (cipsm.de)
  • MLE core is an unusual DExH helicase that can unwind blunt-ended RNA duplexes and has specificity for uridine nucleotides. (cipsm.de)
  • The OB-like and dsRBD folds bind the DExH module and contribute to form the entrance of the helicase channel. (cipsm.de)
  • The RNA helicase database stores data (sequence, structures. (wikipedia.org)
  • van Hoof, A., Lennertz, P. & Parker, R. Yeast exosome mutants accumulate 3′-extended polyadenylated forms of U4 small nuclear RNA and small nucleolar RNAs. (nature.com)
  • The shield prevents Pol I from producing sense intergenic noncoding RNAs (sincRNAs) that can disrupt nucleolar organization and rRNA expression. (nature.com)
  • We reveal a nucleolar Pol-II-dependent mechanism that drives ribosome biogenesis, identify disease-associated disruption of nucleoli by noncoding RNAs, and establish locus-targeted R-loop modulation. (nature.com)
  • Traditionally, the nucleolar Pol I and nucleoplasmic Pol III are viewed as the sole mammalian RNA polymerases that directly mediate housekeeping ribosome biogenesis. (nature.com)
  • We loaded a human exosome with an optimized DNA-RNA chimera that stalls MTR4 during unwinding and determined its structure to an overall resolution of 3.45 Å by cryoelectron microscopy (cryo-EM). (rcsb.org)
  • EXOSC10 remains bound to the core, but its catalytic module and cofactor C1D are displaced by RNA-engaged MTR4. (rcsb.org)
  • 2023). Genome-wide RNA binding analysis of C9orf72 poly(PR) dipeptides. (upenn.edu)
  • Some helicases unwind DNA as well as RNA (4,9). (cathdb.info)
  • Some of them unwind RNA with a 3' to 5' polarity, other show 5' to 3' polarity. (cathdb.info)
  • RNA genome. (cdc.gov)
  • LOCUS AB187514 7746 bp RNA linear VRL 01-SEP-2005 DEFINITION Norovirus Hu/GI/Otofuke/1979/JP genomic RNA, complete genome. (cdc.gov)
  • Inclusion of Mtr4p within the TRAMP complex increases the rate constant for unwinding initiation but does not change the characteristics of Mtr4p's helicase mechanism. (nature.com)
  • In situ poly(A) hybridization indicates that the export of poly(A) + RNAs is blocked in the cryophyte/los4-2 mutant at warm or high temperatures but not at low temperatures, whereas the los4-1 mutation weakens mRNA export at both low and warm temperatures. (edu.sa)
  • These results demonstrate an important role of the CRYOPHYTE/LOS4 RNA helicase in mRNA export, plant development, and stress responses. (edu.sa)
  • 7746 /organism="Norovirus Hu/GI/Otofuke/1979/JP" /mol_type="genomic RNA" /strain="Otofuke" /db_xref="taxon:290280" /country="Japan" CDS 5. (cdc.gov)
  • These two superfamilies encompass a large number of DNA and RNA helicases from archaea, eubacteria, eukaryotes and viruses that seem to be active as monomers or dimers. (embl.de)
  • Here, single-molecule high-resolution optical trapping measurements reveal that Mtr4p unwinds RNA duplexes by 3′-to-5′ translocation on the loading strand, that strand separation occurs in discrete steps of 6 base pairs and that a single Mtr4p molecule performs consecutive unwinding steps. (nature.com)
  • Our data indicate that Mtr4p utilizes a previously unknown unwinding mode that combines aspects of canonical translocating helicases and non-canonical duplex-sensing helicases, thereby restricting directional translocation to duplex regions. (nature.com)
  • Analysis of the relative rates of synonymous (dS) and nonsynonymous (dN) substitutions revealed that the RNA helicase genes were subjected to strong negative (purifying) selection. (syr.edu)
  • Meta-analysis was conducted to determine expression of the RNA helicase genes during the critical period (90-110 days post-fertilization, dpf) of male gonad differentiation. (syr.edu)
  • In general, the vast majority of the RNA helicase genes (31) were expressed at higher levels in females than in males. (syr.edu)
  • Cluster identity was assigned based on the top 10 marker genes of each cluster ( Table S2 ), followed by inspection of RNA in situ hybridization patterns. (stowers.org)
  • These findings suggested that RNA helicases may play important roles in sex development and differentiation in teleosts. (syr.edu)
  • DDX60, a DEXD/H box helicase, is a novel antiviral factor promoting RIG-I-like receptor-mediated signaling. (nih.gov)
  • The HCMV helicase-primase complex (pUL105-pUL102-pUL70) is essential for viral DNA replication and could thus be a relevant antiviral target. (frontiersin.org)
  • Bernstein, J. & Toth, E.A. Yeast nuclear RNA processing. (nature.com)
  • Ten of the fifteen mutations cause premature termination of a large DEAxQ-box helicase, the human ortholog of yeast Sen1p, involved in RNA maturation and termination. (nih.gov)
  • Violin plots show distribution of expression levels for ATP-dependent RNA helicase DHX8 (SMED30020946) in cells (dots) of each of the 12 neoblast clusters. (stowers.org)
  • Expression of ATP-dependent RNA helicase DHX8 (SMED30020946) in the t-SNE clustered sub-lethally irradiated X1 and X2 cells. (stowers.org)
  • Anderson, J.T. & Wang, X. Nuclear RNA surveillance: no sign of substrates tailing off. (nature.com)
  • Schmidt, K. & Butler, J.S. Nuclear RNA surveillance: role of TRAMP in controlling exosome specificity. (nature.com)
  • RNAs, including long noncoding RNAs (lncRNA), are known to be abundant and important structural components of the nuclear infrastructure. (harvard.edu)
  • The structure reveals an RNA-engaged helicase atop the non-catalytic core, with RNA captured within the central channel and DIS3 exoribonuclease active site. (rcsb.org)
  • The product Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA) is intended to be used for research purposes only. (rnagrade.com)
  • The product Assay kit for Guinea pig Probable ATP-dependent RNA helicase DDX17(DDX17) (ELISA) should be kept between two and eight degrees Celsius to ensure the retention of the stability and reactivity of the reagents included in the kit. (rnagrade.com)
  • Promising new inhibitors that target the viral helicase-primase complex have been reported to block replication of herpes simplex and varicella-zoster viruses, but they have no activity against human cytomegalovirus (HCMV), another herpesvirus. (frontiersin.org)
  • Replication of plus-strand RNA viruses depends on recruited host factors that aid several critical steps during replication. (prolekarniky.cz)
  • However, the functions of host factors in (+)RNA virus replication are known only for a small number of host factors [1] - [9] . (prolekarniky.cz)
  • However, the role of RNA homeostasis in aging processes remains unknown. (postech.ac.kr)
  • We also find that Ded1p is a component of the tombusvirus replicase complex and Ded1p binds to the 3′-end of the viral minus-stranded RNA. (prolekarniky.cz)
  • In addition, we have developed an in vitro assay for Flock house virus (FHV), a small RNA virus of insects, that also demonstrated positive effect on FHV replicase activity by the added Ded1p helicase. (prolekarniky.cz)
  • After the assembly of the membrane-bound viral replicase complexes (VRC), the viral replicase uses the viral RNA as a template to produce complementary (−)RNA. (prolekarniky.cz)
  • Because HEL-1 and IIS are evolutionarily well conserved, a similar mechanism for longevity regulation via an RNA helicase-dependent regulation of FOXO signaling may operate in mammals, including humans. (postech.ac.kr)
  • RNA helicase activity of Mtr4p is critical for biological functions of the enzyme, but the molecular basis for RNA unwinding is not understood. (nature.com)
  • It has a DNA unwinding activity characteristic of helicases with a 3' to 5' polarity. (embl.de)
  • It acts by opening DNA either around the RNA transcription start site or the DNA. (embl.de)
  • Bacterial ATP-dependent DNA helicase recG. (embl.de)