RNA, Messenger: 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.RNA: 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)RNA, Small Interfering: 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.RNA, Viral: Ribonucleic acid that makes up the genetic material of viruses.RNA Splicing: The ultimate exclusion of nonsense sequences or intervening sequences (introns) before the final RNA transcript is sent to the cytoplasm.RNA Editing: 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).Second Messenger Systems: Systems in which an intracellular signal is generated in response to an intercellular primary messenger such as a hormone or neurotransmitter. They are intermediate signals in cellular processes such as metabolism, secretion, contraction, phototransduction, and cell growth. Examples of second messenger systems are the adenyl cyclase-cyclic AMP system, the phosphatidylinositol diphosphate-inositol triphosphate system, and the cyclic GMP system.RNA, Ribosomal: 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, Bacterial: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.DNA-Directed RNA Polymerases: 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).RNA Interference: 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.RNA Viruses: Viruses whose genetic material is RNA.RNA, Double-Stranded: 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.RNA, Catalytic: 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.RNA Folding: The processes of RNA tertiary structure formation.RNA Polymerase II: 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.RNA Stability: 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.RNA, Fungal: Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.RNA Processing, Post-Transcriptional: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.RNA, Transfer: 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.RNA, Antisense: 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.RNA Helicases: A family of proteins that promote unwinding of RNA during splicing and translation.Nucleic Acid Conformation: The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.RNA Precursors: 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.RNA, Small Nuclear: 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.RNA, Untranslated: 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.RNA Caps: 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.Molecular Sequence Data: 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.Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.RNA, Neoplasm: RNA present in neoplastic tissue.Sequence Analysis, RNA: A multistage process that includes cloning, physical mapping, subcloning, sequencing, and information analysis of an RNA SEQUENCE.RNA, Plant: Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.RNA, Protozoan: Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)RNA Ligase (ATP): An enzyme that catalyzes the conversion of linear RNA to a circular form by the transfer of the 5'-phosphate to the 3'-hydroxyl terminus. It also catalyzes the covalent joining of two polyribonucleotides in phosphodiester linkage. EC 6.5.1.3.DEAD-box RNA Helicases: 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.Poly A: A group of adenine ribonucleotides in which the phosphate residues of each adenine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.RNA-Binding Proteins: Proteins that bind to RNA molecules. Included here are RIBONUCLEOPROTEINS and other proteins whose function is to bind specifically to RNA.Amino Acid Sequence: 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.Polyribosomes: A multiribosomal structure representing a linear array of RIBOSOMES held together by messenger RNA; (RNA, MESSENGER); They represent the active complexes in cellular protein synthesis and are able to incorporate amino acids into polypeptides both in vivo and in vitro. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.RNA Transport: The process of moving specific RNA molecules from one cellular compartment or region to another by various sorting and transport mechanisms.RNA Polymerase III: A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. It functions in the nucleoplasmic structure where it transcribes DNA into RNA. It has specific requirements for cations and salt and has shown an intermediate sensitivity to alpha-amanitin in comparison to RNA polymerase I and II. EC 2.7.7.6.Cell Line: Established cell cultures that have the potential to propagate indefinitely.RNA Polymerase I: A DNA-dependent RNA polymerase present in bacterial, plant, and animal cells. The enzyme functions in the nucleolar structure and transcribes DNA into RNA. It has different requirements for cations and salts than RNA polymerase II and III and is not inhibited by alpha-amanitin. EC 2.7.7.6.RNA, Guide: Small kinetoplastid mitochondrial RNA that plays a major role in RNA EDITING. These molecules form perfect hybrids with edited mRNA sequences and possess nucleotide sequences at their 5'-ends that are complementary to the sequences of the mRNA's immediately downstream of the pre-edited regions.RNA, Nuclear: RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm.Ribonucleoproteins: Complexes of RNA-binding proteins with ribonucleic acids (RNA).RNA, Ribosomal, 28S: Constituent of the 60S subunit of eukaryotic ribosomes. 28S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.RNA, Ribosomal, 18S: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.Reverse Transcriptase Polymerase Chain Reaction: A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.Mutation: 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.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Escherichia coli: 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.Gene Expression Regulation: 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.DNA: 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).Ribonucleases: Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.Kinetics: The rate dynamics in chemical or physical systems.RNA, Ribosomal, 23S: Constituent of 50S subunit of prokaryotic ribosomes containing about 3200 nucleotides. 23S rRNA is involved in the initiation of polypeptide synthesis.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.UridineOligoribonucleotides: A group of ribonucleotides (up to 12) in which the phosphate residues of each ribonucleotide act as bridges in forming diester linkages between the ribose moieties.Ribosomes: Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.RNA, Spliced Leader: The small RNAs which provide spliced leader sequences, SL1, SL2, SL3, SL4 and SL5 (short sequences which are joined to the 5' ends of pre-mRNAs by TRANS-SPLICING). They are found primarily in primitive eukaryotes (protozoans and nematodes).RNA, Satellite: Small, linear single-stranded RNA molecules functionally acting as molecular parasites of certain RNA plant viruses. Satellite RNAs exhibit four characteristic traits: (1) they require helper viruses to replicate; (2) they are unnecessary for the replication of helper viruses; (3) they are encapsidated in the coat protein of the helper virus; (4) they have no extensive sequence homology to the helper virus. Thus they differ from SATELLITE VIRUSES which encode their own coat protein, and from the genomic RNA; (=RNA, VIRAL); of satellite viruses. (From Maramorosch, Viroids and Satellites, 1991, p143)HeLa Cells: 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.Cell-Free System: A fractionated cell extract that maintains a biological function. A subcellular fraction isolated by ultracentrifugation or other separation techniques must first be isolated so that a process can be studied free from all of the complex side reactions that occur in a cell. The cell-free system is therefore widely used in cell biology. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p166)RNA, Ribosomal, 16S: Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Protein Binding: 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.Virus Replication: 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, Heterogeneous Nuclear: Nuclear nonribosomal RNA larger than about 1000 nucleotides, the mass of which is rapidly synthesized and degraded within the cell nucleus. Some heterogeneous nuclear RNA may be a precursor to mRNA. However, the great bulk of total hnRNA hybridizes with nuclear DNA rather than with mRNA.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.RNA, Archaeal: Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.Cell Nucleus: 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)Templates, Genetic: Macromolecular molds for the synthesis of complementary macromolecules, as in DNA REPLICATION; GENETIC TRANSCRIPTION of DNA to RNA, and GENETIC TRANSLATION of RNA into POLYPEPTIDES.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.RNA 3' End Processing: The steps that generate the 3' ends of mature RNA molecules. For most mRNAs (RNA, MESSENGER), 3' end processing referred to as POLYADENYLATION includes the addition of POLY A.DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Promoter Regions, Genetic: DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.Dactinomycin: A compound composed of a two CYCLIC PEPTIDES attached to a phenoxazine that is derived from STREPTOMYCES parvullus. It binds to DNA and inhibits RNA synthesis (transcription), with chain elongation more sensitive than initiation, termination, or release. As a result of impaired mRNA production, protein synthesis also declines after dactinomycin therapy. (From AMA Drug Evaluations Annual, 1993, p2015)RNA Cleavage: A reaction that severs one of the sugar-phosphate linkages of the phosphodiester backbone of RNA. It is catalyzed enzymatically, chemically, or by radiation. Cleavage may be exonucleolytic, or endonucleolytic.TritiumRNA, Small Untranslated: Short RNA, about 200 base pairs in length or shorter, that does not code for protein.Reticulocytes: Immature ERYTHROCYTES. In humans, these are ERYTHROID CELLS that have just undergone extrusion of their CELL NUCLEUS. They still contain some organelles that gradually decrease in number as the cells mature. RIBOSOMES are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the ENDOPLASMIC RETICULUM), hence the name reticulocytes.Molecular Weight: The sum of the weight of all the atoms in a molecule.Centrifugation, Density Gradient: Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Endoribonucleases: A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.RNA, Small Cytoplasmic: Small RNAs found in the cytoplasm usually complexed with proteins in scRNPs (RIBONUCLEOPROTEINS, SMALL CYTOPLASMIC).3' Untranslated Regions: The sequence at the 3' end of messenger RNA that does not code for product. This region contains transcription and translation regulating sequences.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Genome, Viral: The complete genetic complement contained in a DNA or RNA molecule in a virus.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.RNA, Ribosomal, 5.8S: Constituent of the 60S subunit of eukaryotic ribosomes. 5.8S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.RNA, Complementary: Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This cRNA can be labeled with radioactive uracil and then used as a probe. (King & Stansfield, A Dictionary of Genetics, 4th ed)Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Calcium: A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)RNA, Long Noncoding: A class of untranslated RNA molecules that are typically greater than 200 nucleotides in length and do not code for proteins. Members of this class have been found to play roles in transcriptional regulation, post-transcriptional processing, CHROMATIN REMODELING, and in the epigenetic control of chromatin.RNA, Small Nucleolar: Small nuclear RNAs that are involved in the processing of pre-ribosomal RNA in the nucleolus. Box C/D containing snoRNAs (U14, U15, U16, U20, U21 and U24-U63) direct site-specific methylation of various ribose moieties. Box H/ACA containing snoRNAs (E2, E3, U19, U23, and U64-U72) direct the conversion of specific uridines to pseudouridine. Site-specific cleavages resulting in the mature ribosomal RNAs are directed by snoRNAs U3, U8, U14, U22 and the snoRNA components of RNase MRP and RNase P.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.RNA Virus InfectionsSaccharomyces cerevisiae: 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.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.PolynucleotidesSingle-Strand Specific DNA and RNA Endonucleases: Enzymes that catalyze the endonucleolytic cleavage of single-stranded regions of DNA or RNA molecules while leaving the double-stranded regions intact. They are particularly useful in the laboratory for producing "blunt-ended" DNA molecules from DNA with single-stranded ends and for sensitive GENETIC TECHNIQUES such as NUCLEASE PROTECTION ASSAYS that involve the detection of single-stranded DNA and RNA.Poly U: A group of uridine ribonucleotides in which the phosphate residues of each uridine ribonucleotide act as bridges in forming diester linkages between the ribose moieties.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Base Pairing: Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Genetic Code: The meaning ascribed to the BASE SEQUENCE with respect to how it is translated into AMINO ACID SEQUENCE. The start, stop, and order of amino acids of a protein is specified by consecutive triplets of nucleotides called codons (CODON).Globins: A superfamily of proteins containing the globin fold which is composed of 6-8 alpha helices arranged in a characterstic HEME enclosing structure.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Protein Structure, Tertiary: 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.5' Untranslated Regions: The sequence at the 5' end of the messenger RNA that does not code for product. This sequence contains the ribosome binding site and other transcription and translation regulating sequences.Plant Viruses: Viruses parasitic on plants higher than bacteria.Oligonucleotides: Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)RNA, Helminth: Ribonucleic acid in helminths having regulatory and catalytic roles as well as involvement in protein synthesis.Cyclic GMP: Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed)RNA, Chloroplast: Ribonucleic acid in chloroplasts having regulatory and catalytic roles as well as involvement in protein synthesis.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.DNA, Viral: Deoxyribonucleic acid that makes up the genetic material of viruses.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.RNA, Messenger, Stored: Messenger RNA that is stored in a masked state for translation at a later time. Distinguish from RNA, UNTRANSLATED which refers to non-messenger RNA, i.e. RNA that does not code for protein.Gene Expression Profiling: The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Peptide Chain Initiation, Translational: A process of GENETIC TRANSLATION whereby the formation of a peptide chain is started. It includes assembly of the RIBOSOME components, the MESSENGER RNA coding for the polypeptide to be made, INITIATOR TRNA, and PEPTIDE INITIATION FACTORS; and placement of the first amino acid in the peptide chain. The details and components of this process are unique for prokaryotic protein biosynthesis and eukaryotic protein biosynthesis.Nucleic Acid Denaturation: Disruption of the secondary structure of nucleic acids by heat, extreme pH or chemical treatment. Double strand DNA is "melted" by dissociation of the non-covalent hydrogen bonds and hydrophobic interactions. Denatured DNA appears to be a single-stranded flexible structure. The effects of denaturation on RNA are similar though less pronounced and largely reversible.Ribonuclease T1: An enzyme catalyzing the endonucleolytic cleavage of RNA at the 3'-position of a guanylate residue. EC 3.1.27.3.Carcinoma, Krebs 2Gene Silencing: Interruption or suppression of the expression of a gene at transcriptional or translational levels.Cyclic ADP-Ribose: A pyridine nucleotide that mobilizes CALCIUM. It is synthesized from nicotinamide adenine dinucleotide (NAD) by ADP RIBOSE CYCLASE.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Cell Line, Tumor: A cell line derived from cultured tumor cells.Introns: Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.Inositol 1,4,5-Trisphosphate: Intracellular messenger formed by the action of phospholipase C on phosphatidylinositol 4,5-bisphosphate, which is one of the phospholipids that make up the cell membrane. Inositol 1,4,5-trisphosphate is released into the cytoplasm where it releases calcium ions from internal stores within the cell's endoplasmic reticulum. These calcium ions stimulate the activity of B kinase or calmodulin.RNA-Directed DNA Polymerase: An enzyme that synthesizes DNA on an RNA template. It is encoded by the pol gene of retroviruses and by certain retrovirus-like elements. EC 2.7.7.49.Conserved Sequence: 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.Bacterial Proteins: Proteins found in any species of bacterium.Alternative Splicing: A process whereby multiple RNA transcripts are generated from a single gene. Alternative splicing involves the splicing together of other possible sets of EXONS during the processing of some, but not all, transcripts of the gene. Thus a particular exon may be connected to any one of several alternative exons to form a mature RNA. The alternative forms of mature MESSENGER RNA produce PROTEIN ISOFORMS in which one part of the isoforms is common while the other parts are different.Amanitins: Cyclic peptides extracted from carpophores of various mushroom species. They are potent inhibitors of RNA polymerases in most eukaryotic species, blocking the production of mRNA and protein synthesis. These peptides are important in the study of transcription. Alpha-amanitin is the main toxin from the species Amanitia phalloides, poisonous if ingested by humans or animals.RNA, Transfer, Phe: A transfer RNA which is specific for carrying phenylalanine to sites on the ribosomes in preparation for protein synthesis.RNA, Transfer, Lys: A transfer RNA which is specific for carrying lysine to sites on the ribosomes in preparation for protein synthesis.Genes, Viral: The functional hereditary units of VIRUSES.Nuclear Proteins: 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.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Inositol Phosphates: Phosphoric acid esters of inositol. They include mono- and polyphosphoric acid esters, with the exception of inositol hexaphosphate which is PHYTIC ACID.RNA Splice Sites: Nucleotide sequences located at the ends of EXONS and recognized in pre-messenger RNA by SPLICEOSOMES. They are joined during the RNA SPLICING reaction, forming the junctions between exons.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Mosaic Viruses: Viruses which produce a mottled appearance of the leaves of plants.RNA, Transfer, Amino Acyl: Intermediates in protein biosynthesis. The compounds are formed from amino acids, ATP and transfer RNA, a reaction catalyzed by aminoacyl tRNA synthetase. They are key compounds in the genetic translation process.Nucleotides: The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Nucleoproteins: Proteins conjugated with nucleic acids.Regulatory Sequences, Ribonucleic Acid: Sequences within RNA that regulate the processing, stability (RNA STABILITY) or translation (TRANSLATION, GENETIC) of RNA.Peptide Biosynthesis: The production of PEPTIDES or PROTEINS by the constituents of a living organism. The biosynthesis of proteins on RIBOSOMES following an RNA template is termed translation (TRANSLATION, GENETIC). There are other, non-ribosomal peptide biosynthesis (PEPTIDE BIOSYNTHESIS, NUCLEIC ACID-INDEPENDENT) mechanisms carried out by PEPTIDE SYNTHASES and PEPTIDYLTRANSFERASES. Further modifications of peptide chains yield functional peptide and protein molecules.Exons: The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.RNA, Transfer, Tyr: A transfer RNA which is specific for carrying tyrosine to sites on the ribosomes in preparation for protein synthesis.Gene Expression Regulation, Viral: Any of the processes by which cytoplasmic factors influence the differential control of gene action in viruses.Nucleic Acid Precursors: Use for nucleic acid precursors in general or for which there is no specific heading.Puromycin: A cinnamamido ADENOSINE found in STREPTOMYCES alboniger. It inhibits protein synthesis by binding to RNA. It is an antineoplastic and antitrypanosomal agent and is used in research as an inhibitor of protein synthesis.Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Open Reading Frames: A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).Cattle: Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.Cell Nucleolus: Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Oligonucleotide Array Sequence Analysis: Hybridization of a nucleic acid sample to a very large set of OLIGONUCLEOTIDE PROBES, which have been attached individually in columns and rows to a solid support, to determine a BASE SEQUENCE, or to detect variations in a gene sequence, GENE EXPRESSION, or for GENE MAPPING.Down-Regulation: A negative regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.Ribosomal Proteins: Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Cycloheximide: Antibiotic substance isolated from streptomycin-producing strains of Streptomyces griseus. It acts by inhibiting elongation during protein synthesis.Up-Regulation: A positive regulatory effect on physiological processes at the molecular, cellular, or systemic level. At the molecular level, the major regulatory sites include membrane receptors, genes (GENE EXPRESSION REGULATION), mRNAs (RNA, MESSENGER), and proteins.HIV-1: The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.Exoribonucleases: A family of enzymes that catalyze the exonucleolytic cleavage of RNA. It includes EC 3.1.13.-, EC 3.1.14.-, EC 3.1.15.-, and EC 3.1.16.-. EC 3.1.-Enzyme Activation: Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Models, Genetic: Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.Polyadenylation: The addition of a tail of polyadenylic acid (POLY A) to the 3' end of mRNA (RNA, MESSENGER). Polyadenylation involves recognizing the processing site signal, (AAUAAA), and cleaving of the mRNA to create a 3' OH terminal end to which poly A polymerase (POLYNUCLEOTIDE ADENYLYLTRANSFERASE) adds 60-200 adenylate residues. The 3' end processing of some messenger RNAs, such as histone mRNA, is carried out by a different process that does not include the addition of poly A as described here.Saccharomyces cerevisiae Proteins: 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.Gene Expression Regulation, Enzymologic: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.DiglyceridesOligonucleotide Probes: Synthetic or natural oligonucleotides used in hybridization studies in order to identify and study specific nucleic acid fragments, e.g., DNA segments near or within a specific gene locus or gene. The probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the probe include the radioisotope labels 32P and 125I and the chemical label biotin.Tobacco: A plant genus of the family SOLANACEAE. Members contain NICOTINE and other biologically active chemicals; its dried leaves are used for SMOKING.Calcium Signaling: Signal transduction mechanisms whereby calcium mobilization (from outside the cell or from intracellular storage pools) to the cytoplasm is triggered by external stimuli. Calcium signals are often seen to propagate as waves, oscillations, spikes, sparks, or puffs. The calcium acts as an intracellular messenger by activating calcium-responsive proteins.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

The surface ectoderm is essential for nephric duct formation in intermediate mesoderm. (1/126162)

The nephric duct is the first epithelial tubule to differentiate from intermediate mesoderm that is essential for all further urogenital development. In this study we identify the domain of intermediate mesoderm that gives rise to the nephric duct and demonstrate that the surface ectoderm is required for its differentiation. Removal of the surface ectoderm resulted in decreased levels of Sim-1 and Pax-2 mRNA expression in mesenchymal nephric duct progenitors, and caused inhibition of nephric duct formation and subsequent kidney development. The surface ectoderm expresses BMP-4 and we show that it is required for the maintenance of high-level BMP-4 expression in lateral plate mesoderm. Addition of a BMP-4-coated bead to embryos lacking the surface ectoderm restored normal levels of Sim-1 and Pax-2 mRNA expression in nephric duct progenitors, nephric duct formation and the initiation of nephrogenesis. Thus, BMP-4 signaling can substitute for the surface ectoderm in supporting nephric duct morphogenesis. Collectively, these data suggest that inductive interactions between the surface ectoderm, lateral mesoderm and intermediate mesoderm are essential for nephric duct formation and the initiation of urogenital development.  (+info)

Apontic binds the translational repressor Bruno and is implicated in regulation of oskar mRNA translation. (2/126162)

The product of the oskar gene directs posterior patterning in the Drosophila oocyte, where it must be deployed specifically at the posterior pole. Proper expression relies on the coordinated localization and translational control of the oskar mRNA. Translational repression prior to localization of the transcript is mediated, in part, by the Bruno protein, which binds to discrete sites in the 3' untranslated region of the oskar mRNA. To begin to understand how Bruno acts in translational repression, we performed a yeast two-hybrid screen to identify Bruno-interacting proteins. One interactor, described here, is the product of the apontic gene. Coimmunoprecipitation experiments lend biochemical support to the idea that Bruno and Apontic proteins physically interact in Drosophila. Genetic experiments using mutants defective in apontic and bruno reveal a functional interaction between these genes. Given this interaction, Apontic is likely to act together with Bruno in translational repression of oskar mRNA. Interestingly, Apontic, like Bruno, is an RNA-binding protein and specifically binds certain regions of the oskar mRNA 3' untranslated region.  (+info)

Difference between mammary epithelial cells from mature virgin and primiparous mice. (3/126162)

Mammary epithelial cells from mature virgin mice are similar to those from primiparous mice in several respects. However, there is one known difference. The cells from the mature virgin must traverse the cell cycle in order to become competent to make casein and enzymatically active alpha-lactalbumin in vitro; those from the primiparous animal can make these proteins without first traversing the cycle. In this regard, cells from human placental lactogen- and prolactin-treated mature virgins are, after involution, similar to those from primiparous mice. The developemental block in the cells from the mature virgin, imposed by preventing cell cycle traversal, has been partially delineated. It does not appear to reside at the levels of ultrastructural maturation or the formation of casein messenger RNA. Rather, the lesion is postranscriptional and may be at the level of translation, or posttranslational modification, or both.  (+info)

Factor VII deficiency rescues the intrauterine lethality in mice associated with a tissue factor pathway inhibitor deficit. (4/126162)

Mice doubly heterozygous for a modified tissue factor pathway inhibitor (TFPI) allele (tfpi delta) lacking its Kunitz-type domain-1 (TFPI+/delta) and for a deficiency of the factor VII gene (FVII+/-) were mated to generate 309 postnatal and 205 embryonic day 17.5 (E17. 5) offspring having all the predicted genotypic combinations. Progeny singly homozygous for the tfpidelta modification but with the wild-type fVII allele (FVII+/+/TFPIdelta/delta), and mice singly homozygous for the fVII deficiency and possessing the wild-type tfpi allele (FVII-/-/TFPI+/+), displayed previously detailed phenotypes (i.e., a high percentage of early embryonic lethality at E9.5 or normal development with severe perinatal bleeding, respectively). Surprisingly, mice of the combined FVII-/-/TFPIdelta/delta genotype were born at the expected mendelian frequency but suffered the fatal perinatal bleeding associated with the FVII-/- genotype. Mice carrying the FVII+/-/TFPIdelta/delta genotype were also rescued from the lethality associated with the FVII+/+/TFPIdelta/delta genotype but succumbed to perinatal consumptive coagulopathy. Thus, the rescue of TFPIdelta/delta embryos, either by an accompanying homozygous or heterozygous FVII deficiency, suggests that diminishment of FVII activity precludes the need for TFPI-mediated inhibition of the FVIIa/tissue factor coagulation pathway during embryogenesis. Furthermore, the phenotypes of these combined deficiency states suggest that embryonic FVII is produced in mice as early as E9.5 and that any level of maternal FVII in early-stage embryos is insufficient to cause a coagulopathy in TFPIdelta/delta mice.  (+info)

TIF1gamma, a novel member of the transcriptional intermediary factor 1 family. (5/126162)

We report the cloning and characterization of a novel member of the Transcriptional Intermediary Factor 1 (TIF1) gene family, human TIF1gamma. Similar to TIF1alpha and TIF1beta, the structure of TIF1beta is characterized by multiple domains: RING finger, B boxes, Coiled coil, PHD/TTC, and bromodomain. Although structurally related to TIF1alpha and TIF1beta, TIF1gamma presents several functional differences. In contrast to TIF1alpha, but like TIF1beta, TIF1 does not interact with nuclear receptors in yeast two-hybrid or GST pull-down assays and does not interfere with retinoic acid response in transfected mammalian cells. Whereas TIF1alpha and TIF1beta were previously found to interact with the KRAB silencing domain of KOX1 and with the HP1alpha, MODI (HP1beta) and MOD2 (HP1gamma) heterochromatinic proteins, suggesting that they may participate in a complex involved in heterochromatin-induced gene repression, TIF1gamma does not interact with either the KRAB domain of KOX1 or the HP1 proteins. Nevertheless, TIF1gamma, like TIF1alpha and TIF1beta, exhibits a strong silencing activity when tethered to a promoter. Since deletion of a novel motif unique to the three TIF1 proteins, called TIF1 signature sequence (TSS), abrogates transcriptional repression by TIF1gamma, this motif likely participates in TIF1 dependent repression.  (+info)

Leptin suppression of insulin secretion and gene expression in human pancreatic islets: implications for the development of adipogenic diabetes mellitus. (6/126162)

Previously we demonstrated the expression of the long form of the leptin receptor in rodent pancreatic beta-cells and an inhibition of insulin secretion by leptin via activation of ATP-sensitive potassium channels. Here we examine pancreatic islets isolated from pancreata of human donors for their responses to leptin. The presence of leptin receptors on islet beta-cells was demonstrated by double fluorescence confocal microscopy after binding of a fluorescent derivative of human leptin (Cy3-leptin). Leptin (6.25 nM) suppressed insulin secretion of normal islets by 20% at 5.6 mM glucose. Intracellular calcium responses to 16.7 mM glucose were rapidly reduced by leptin. Proinsulin messenger ribonucleic acid expression in islets was inhibited by leptin at 11.1 mM, but not at 5.6 mM glucose. Leptin also reduced proinsulin messenger ribonucleic acid levels that were increased in islets by treatment with 10 nM glucagon-like peptide-1 in the presence of either 5.6 or 11.1 mM glucose. These findings demonstrate direct suppressive effects of leptin on insulin-producing beta-cells in human islets at the levels of both stimulus-secretion coupling and gene expression. The findings also further indicate the existence of an adipoinsular axis in humans in which insulin stimulates leptin production in adipocytes and leptin inhibits the production of insulin in beta-cells. We suggest that dysregulation of the adipoinsular axis in obese individuals due to defective leptin reception by beta-cells may result in chronic hyperinsulinemia and may contribute to the pathogenesis of adipogenic diabetes.  (+info)

Differential stability of the DNA-activated protein kinase catalytic subunit mRNA in human glioma cells. (7/126162)

DNA-dependent protein kinase (DNA-PK) functions in double-strand break repair and immunoglobulin [V(D)J] recombination. We previously established a radiation-sensitive human cell line, M059J, derived from a malignant glioma, which lacks the catalytic subunit (DNA-PKcs) of the DNA-PK multiprotein complex. Although previous Northern blot analysis failed to detect the DNA-PKcs transcript in these cells, we show here through quantitative studies that the transcript is present, albeit at greatly reduced (approximately 20x) levels. Sequencing revealed no genetic alteration in either the promoter region, the kinase domain, or the 3' untranslated region of the DNA-PKcs gene to account for the reduced transcript levels. Nuclear run-on transcription assays indicated that the rate of DNA-PKcs transcription in M059J and DNA-PKcs proficient cell lines was similar, but the stability of the DNA-PKcs message in the M059J cell line was drastically (approximately 20x) reduced. Furthermore, M059J cells lack an alternately spliced DNA-PKcs transcript that accounts for a minor (5-20%) proportion of the DNA-PKcs message in all other cell lines tested. Thus, alterations in DNA-PKcs mRNA stability and/or the lack of the alternate mRNA may result in the loss of DNA-PKcs activity. This finding has important implications as DNA-PKcs activity is essential to cells repairing damage induced by radiation or radiomimetric agents.  (+info)

Alternative sulfonylurea receptor expression defines metabolic sensitivity of K-ATP channels in dopaminergic midbrain neurons. (8/126162)

ATP-sensitive potassium (K-ATP) channels couple the metabolic state to cellular excitability in various tissues. Several isoforms of the K-ATP channel subunits, the sulfonylurea receptor (SUR) and inwardly rectifying K channel (Kir6.X), have been cloned, but the molecular composition and functional diversity of native neuronal K-ATP channels remain unresolved. We combined functional analysis of K-ATP channels with expression profiling of K-ATP subunits at the level of single substantia nigra (SN) neurons in mouse brain slices using an RT-multiplex PCR protocol. In contrast to GABAergic neurons, single dopaminergic SN neurons displayed alternative co-expression of either SUR1, SUR2B or both SUR isoforms with Kir6.2. Dopaminergic SN neurons expressed alternative K-ATP channel species distinguished by significant differences in sulfonylurea affinity and metabolic sensitivity. In single dopaminergic SN neurons, co-expression of SUR1 + Kir6.2, but not of SUR2B + Kir6.2, correlated with functional K-ATP channels highly sensitive to metabolic inhibition. In contrast to wild-type, surviving dopaminergic SN neurons of homozygous weaver mouse exclusively expressed SUR1 + Kir6.2 during the active period of dopaminergic neurodegeneration. Therefore, alternative expression of K-ATP channel subunits defines the differential response to metabolic stress and constitutes a novel candidate mechanism for the differential vulnerability of dopaminergic neurons in response to respiratory chain dysfunction in Parkinson's disease.  (+info)

  • We identified over 3,000 cellular RNA targets of YTHDF2, most of which are mRNAs, but which also include non-coding RNAs, with a conserved core motif of G(m(6)A)C. We further establish the role of YTHDF2 in RNA metabolism, showing that binding of YTHDF2 results in the localization of bound mRNA from the translatable pool to mRNA decay sites, such as processing bodies. (nih.gov)
  • Messenger ribonucleic acids (mRNAs) are molecules that represent the intermediate step in the conversion of genetic information carried in a cell's DNA (deoxyribonucleic acid) into functional proteins. (els.net)
  • The translation and stability of many mRNAs is regulated by small regulatory RNAs (sRNAs). (els.net)
  • RNA-binding proteins (RBP) are involved in ( 1 ) splicing and alternative splicing of hnRNA, resulting in the formation of mRNAs. (mdpi.com)
  • A lot is known about how mRNAs are made, but much less is understood about the mechanisms that control their destruction," said Michael Bender, Ph.D., who oversees RNA processing grants at the National Institutes of Health's National Institute of General Medical Sciences. (eurekalert.org)
  • mRNAs coexpressed with pleiotropic miRNAs were enriched for RNA metabolism (miR-505-5p), ubiquitin-dependent protein catabolism (miR-197-3p, miR-328) and chromatin assembly (miR-328). (harvard.edu)
  • One is nonsense‐mediated mRNA decay (NMD), an RNA surveillance mechanism that rapidly degrades mRNAs harboring premature termination codons (PTCs). (embopress.org)
  • A*STAR researchers have developed a rapid, high-throughput screening procedure that can detect RNA aptamers-special messenger RNA molecules (mRNAs) able to sense and respond to particular cellular chemicals-in a sea of normal mRNA extracted from cells. (phys.org)
  • PURPOSE: To determine the temporal and spatial localization of the messenger RNAs (mRNAs) for the two collagen alpha 1(IX) isoforms during early development of the embryonic chicken eye. (arvojournals.org)
  • We investigated differential expression between paired carcinoma and normal colorectal mucosa of messenger RNAs (mRNAs) and miRNAs using RNA-Seq and Agilent Human miRNA Microarray V19.0 data, respectively, using a negative binomial mixed effects model to test 122 JAK-STAT-signaling genes in 217 colorectal cancer (CRC) cases. (impactjournals.com)
  • We postulated that mRNAs carrying Alus in the two opposite directions can generate double stranded RNAs, capable of regulating the levels of other Alu-carrying mRNAs post-transcriptionally. (wikigenes.org)
  • The cellular and tissue distribution of the sst1-5 messenger RNAs (mRNAs) were studied in the rat GI tract using in situ hybridization histochemistry (ISHH). (semanticscholar.org)
  • Despite the advantages over DNA and viral vectors, RNA-based therapeutics have been plagued by problems of poor translatability, stability, and adverse immune reactions. (pnas.org)
  • The work is a collaboration between the Verma lab and Arcturus Therapeutics, a local biotech company that developed a system of encapsulating messenger RNA within lipid (fatty acid) nanoparticles. (salk.edu)
  • Strategic research and clinical partnership will advance state-of-the-art discoveries on the use of messenger RNA (mRNA) Therapeutics™ to treat serious diseases. (fiercebiotech.com)
  • CAMBRIDGE, Mass. and STOCKHOLM, Sweden, October 16, 2014-Moderna Therapeutics today announced a strategic, long-term collaboration with Karolinska Institutet (KI) and Karolinska University Hospital (KUH) for the discovery and development of innovative drugs using Moderna's messenger RNA (mRNA) Therapeutics™ technology. (fiercebiotech.com)
  • Moderna, Inc., (Nasdaq: MRNA) a clinical stage biotechnology company pioneering messenger RNA (mRNA) therapeutics and vaccines to create a new generation of transformative medicines for patients, today announced positive data in the first analysis of safety and activity in its Phase 1 study evaluating escalating doses of mRNA-1944 administered via intravenous infusion in healthy adults. (barrons.com)
  • AstraZeneca today announced an exclusive agreement with Moderna Therapeutics to discover, develop and commercialise pioneering messenger RNA therapeutics™ for the treatment of serious cardiovascular, metabolic and renal diseases as well as cancer. (astrazeneca.com)
  • Messenger RNA therapeutics™ are an entirely new treatment approach that enables the body to produce therapeutic protein in vivo, opening up new treatment options for a wide range of diseases that cannot be addressed today using existing technologies. (astrazeneca.com)
  • AstraZeneca will lead the preclinical, clinical development and commercialisation of therapeutics resulting from the agreement and Moderna will be responsible for designing and manufacturing the messenger RNA against selected targets. (astrazeneca.com)
  • noun The form of RNA that mediates the transfer of genetic information from the cell nucleus to ribosomes in the cytoplasm, where it serves as a template for protein synthesis. (wordnik.com)
  • The vaccines, icy concoctions of fatty spheres and genetic instructions , used a previously unproven technology based on messenger RNA and had been built and tested in under a year, thanks to discoveries the pair made starting 20 years earlier. (technologyreview.com)
  • Many genetic diseases are linked to mutations that can cause mis-regulation of RNA destruction so it's important to know the when, where and how the cell normally controls the process of mRNA decay," said Dr. Coller. (eurekalert.org)
  • The studies presented provide an insight into molecular and genetic aspects of messenger RNA. (springer.com)
  • However, the direct delivery of nucleic acids to correct a genetic disorder has numerous limitations owing to the inability of naked nucleic acids (DNA and RNA) to traverse the cell membrane. (rsc.org)
  • We have discovered that substances called ribonucleic acids (RNA), which carry the genetic instructions for the production of telomerase, can be used to overcome this problem and stimulate a strong immune response in cancer patients. (bioportfolio.com)
  • We examined associations of mRNA and miRNA levels with 6 CM traits: body mass index, HDL-cholesterol and triglycerides, fasting glucose, and systolic and diastolic blood pressures through cross-sectional analysis of 2812 Framingham Heart Study who had whole blood collection for RNA isolation for mRNA and miRNA expression studies and who consented to genetic research. (harvard.edu)
  • Soukup, G. A. & Breaker, R. R. Relationship between internucleotide linkage geometry and the stability of RNA. (nature.com)
  • Incremental improvements (5′ caps, codon optimization, use of optimized 5′ and 3′ UTRs, poly(A) modifications, modified nucleosides like 5-methyl cytosine (5MC), pseudouridine and 2 thio-UTP, etc.) have substantially improved the stability and translatability of RNAs while also making them immunologically silent. (pnas.org)
  • The presence of angiotensinogen messenger RNA (mRNA) was assessed in total RNA extracted from hepatoma, glioma, neuroblastoma, and glioma-neuroblastoma hybrid cell lines. (ahajournals.org)
  • Accordingly, mRNA levels in total RNA extracted from 13 human breast cancer cell lines were measured by Northern analysis employing complementary DNA probes for the human oestrogen (ER), progesterone (PR), androgen (AR), vitamin D3 (VDR) and glucocorticoid receptors (GR). The 7 ER+ lines expressed a single 6.4 kilobases (kb) ER mRNA. (garvan.org.au)
  • The sequence of bases on a segment of DNA called a gene is copied to a strand of RNA with the assistance of RNA polymerase. (gsu.edu)
  • Aliquots containing 5 μg of total cellular RNA were reverse transcribed, and first-strand cDNA was used as a template in polymerase chain reaction (PCR). (ahajournals.org)
  • Five micrograms of RNA was reverse transcribed into cDNA and l- μ g aliquots subjected to polymerase chain reaction (PCR) amplification for 25 cycles using 32 P-labeled primers specific for rat cytokines and glyeeraldehyde-3-phosphate dehydrogenase (G3PD), a housekeeping gene. (pubmedcentralcanada.ca)
  • Sections of paraffin-embedded lymph nodes were obtained from each patient and were pooled, and their RNA was analyzed by reverse transcriptase polymerase chain reaction (RT-PCR). (annals.org)
  • A third class of RNA-based treatments has stirred excitement over the past 10-20 years, with specific technologies like antisense, RNA interference , and microRNA therapy that seek to precisely alter disease processes at the molecular level. (xconomy.com)
  • In a different section of this work, a new synthetic lethal screen was developed using antisense RNA regulated R1 plasmids. (bl.uk)
  • Whereas traditional vaccine development involves inoculation with an attenuated form of the virus or with a noninfectious antigen derived from a viral protein, two groups, Moderna (in collaboration with the National Institutes of Health) and BioNTech (in collaboration with Pfizer) are taking a novel approach: directly administering to patients messenger RNA, or mRNA, that encodes viral antigens. (asbmb.org)
  • Total RNA from 1 X 10(7) cells was extracted, transferred to a membrane, and hybridized with a 32P-labeled, full-length (1650-base pair) rat angiotensinogen complementary DNA (cDNA). (ahajournals.org)
  • The discovery of messenger RNA more than twenty years ago led to a series of studies on its organization and function in cells in the presence of infecting viruses. (springer.com)
  • That's short for messenger RNA, which is how your DNA sends blueprints to the protein-assembly factories of your cells. (salk.edu)
  • The approach was to extract the follicle cells with Triton X-100 and determine whether mRNA persisted in the insoluble residue by two methods, in situ hybridization with poly(U) and actin DNA probes and the incorporation of radioactive isotopes into RNA. (rupress.org)
  • Triton X-100 extraction of follicle cells yielded a filamentous CF containing approximately 70% of the total poly (A) but only 9% of the total lipid, 23% of the total protein, and 28% of the total RNA. (rupress.org)
  • RNA molecules carry out widely diverse functions in numerous different physiological processes in living cells. (biologists.org)
  • In the past few years, a variety of bright and photo-stable labelling techniques have been developed to generate sufficient contrast for imaging of single endogenous RNAs in vivo . (biologists.org)
  • Although the concepts presented are applicable to all types of RNA, we showcase here the wealth of information gained from in vivo imaging of single particles by discussing studies investigating dynamics of intranuclear trafficking, nuclear pore transport and cytoplasmic transport of endogenous messenger RNA. (biologists.org)
  • That the RNA was intact was ensured by hybridizing duplicate Northern blots to a 32P-labeled actin cDNA. (ahajournals.org)
  • Previous reports showed that herpes simplex virus RNA entering the cytoplasm has a terminal oligonucleotide structure consistent with 7mG(5')ppp-(5')XmpYmpNp and that, whereas the viral RNA made early in infection contained methylated mononucleotides, the RNA made late did not. (eurekamag.com)
  • Utzinger, Maximilian (2017): PLGA-based micro- and nanoparticle development for chemically modified messenger RNA delivery. (uni-muenchen.de)