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.
A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
An enzyme that activates tyrosine with its specific transfer RNA. EC 6.1.1.1.
The sequential set of three nucleotides in TRANSFER RNA that interacts with its complement in MESSENGER RNA, the CODON, during translation in the ribosome.
A transfer RNA which is specific for carrying glutamic acid to sites on the ribosomes in preparation for protein synthesis.
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 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.
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.
An enzyme that activates alanine with its specific transfer RNA. EC 6.1.1.7.
A reaction that introduces an aminoacyl group to a molecule. TRANSFER RNA AMINOACYLATION is the first step in GENETIC TRANSLATION.
A transfer RNA which is specific for carrying tyrosine to sites on the ribosomes in preparation for protein synthesis.
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).
An enzyme that activates serine with its specific transfer RNA. EC 6.1.1.11.
A transfer RNA which is specific for carrying proline to sites on the ribosomes in preparation for protein synthesis.
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)
Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
Enzymes that catalyze the S-adenosyl-L-methionine-dependent methylation of ribonucleotide bases within a transfer RNA molecule. EC 2.1.1.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
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.
Ribonucleic acid that makes up the genetic material of viruses.
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.
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.
A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).
A transfer RNA which is specific for carrying valine to sites on the ribosomes in preparation for protein synthesis.
The ultimate exclusion of nonsense sequences or intervening sequences (introns) before the final RNA transcript is sent to 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).
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)
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A group of transfer RNAs which are specific for carrying each one of the 20 amino acids to the ribosome in preparation for protein synthesis.
The introduction of functional (usually cloned) GENES into cells. A variety of techniques and naturally occurring processes are used for the gene transfer such as cell hybridization, LIPOSOMES or microcell-mediated gene transfer, ELECTROPORATION, chromosome-mediated gene transfer, TRANSFECTION, and GENETIC TRANSDUCTION. Gene transfer may result in genetically transformed cells and individual organisms.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
A transfer RNA which is specific for carrying serine to sites on the ribosomes in preparation for protein synthesis.
A transfer RNA which is specific for carrying phenylalanine to sites on the ribosomes in preparation for protein synthesis.
Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.
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).
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.
The naturally occurring transmission of genetic information between organisms, related or unrelated, circumventing parent-to-offspring transmission. Horizontal gene transfer may occur via a variety of naturally occurring processes such as GENETIC CONJUGATION; GENETIC TRANSDUCTION; and TRANSFECTION. It may result in a change of the recipient organism's genetic composition (TRANSFORMATION, GENETIC).
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.
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.
Viruses whose genetic material is RNA.
A transfer RNA which is specific for carrying tryptophan to sites on the ribosomes in preparation for protein synthesis.
The transfer of mammalian embryos from an in vivo or in vitro environment to a suitable host to improve pregnancy or gestational outcome in human or animal. In human fertility treatment programs, preimplantation embryos ranging from the 4-cell stage to the blastocyst stage are transferred to the uterine cavity between 3-5 days after FERTILIZATION IN VITRO.
A transfer RNA which is specific for carrying methionine to sites on the ribosomes. During initiation of protein synthesis, tRNA(f)Met in prokaryotic cells and tRNA(i)Met in eukaryotic cells binds to the start codon (CODON, INITIATOR).
A transfer RNA which is specific for carrying glycine to sites on the ribosomes in preparation for protein synthesis.
A transfer RNA which is specific for carrying arginine to sites on the ribosomes in preparation for protein synthesis.
A transfer RNA which is specific for carrying alanine to sites on the ribosomes in preparation for protein synthesis.
A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.
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.
A transfer RNA which is specific for carrying isoleucine to sites on the ribosomes in preparation for protein synthesis.
A transfer RNA which is specific for carrying aspartic acid to sites on the ribosomes in preparation for protein synthesis.
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 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 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.
The processes of RNA tertiary structure formation.
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.
A transfer RNA which is specific for carrying histidine to sites on the ribosomes in preparation for protein synthesis.
A transfer RNA which is specific for carrying glutamine to sites on the ribosomes in preparation for protein synthesis.
The rate dynamics in chemical or physical systems.
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.
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.
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 family of proteins that promote unwinding of RNA during splicing and translation.
Change in learning in one situation due to prior learning in another situation. The transfer can be positive (with second learning improved by first) or negative (where the reverse holds).
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.
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.
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.
A type of FLUORESCENCE SPECTROSCOPY using two FLUORESCENT DYES with overlapping emission and absorption spectra, which is used to indicate proximity of labeled molecules. This technique is useful for studying interactions of molecules and PROTEIN FOLDING.
Enzyme that catalyzes the movement of a methyl group from S-adenosylmethionone to a catechol or a catecholamine.
A transfer RNA which is specific for carrying threonine to sites on the ribosomes in preparation for protein synthesis.
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.
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.
Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.
Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.
A multistage process that includes cloning, physical mapping, subcloning, sequencing, and information analysis of an RNA SEQUENCE.
Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
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.
Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.
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.-.
A transfer RNA which is specific for carrying cysteine to sites on the ribosomes in preparation for protein synthesis.
A photoactivable URIDINE analog that is used as an affinity label.
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.
Form of passive immunization where previously sensitized immunologic agents (cells or serum) are transferred to non-immune recipients. When transfer of cells is used as a therapy for the treatment of neoplasms, it is called adoptive immunotherapy (IMMUNOTHERAPY, ADOPTIVE).
DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.
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.
RNA present in neoplastic tissue.
Established cell cultures that have the potential to propagate indefinitely.
Uridine is a nucleoside, specifically a derivative of pyrimidine, that is composed of a uracil molecule joined to a ribose sugar molecule through a β-N1 glycosidic bond, and has significant roles in RNA synthesis, energy transfer, and cell signaling.
Interfacility or intrahospital transfer of patients. Intrahospital transfer is usually to obtain a specific kind of care and interfacility transfer is usually for economic reasons as well as for the type of care provided.
A ubiquitous family of proteins that transport PHOSPHOLIPIDS such as PHOSPHATIDYLINOSITOL and PHOSPHATIDYLCHOLINE between membranes. They play an important role in phospholipid metabolism during vesicular transport and SIGNAL TRANSDUCTION.
Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.
Mutation process that restores the wild-type PHENOTYPE in an organism possessing a mutationally altered GENOTYPE. The second "suppressor" mutation may be on a different gene, on the same gene but located at a distance from the site of the primary mutation, or in extrachromosomal genes (EXTRACHROMOSOMAL INHERITANCE).
Proteins found in any species of bacterium.
The addition of an organic acid radical into a molecule.
Factor derived from leukocyte lysates of immune donors which can transfer both local and systemic cellular immunity to nonimmune recipients.
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.
An RNA-containing enzyme that plays an essential role in tRNA processing by catalyzing the endonucleolytic cleavage of TRANSFER RNA precursors. It removes the extra 5'-nucleotides from tRNA precursors to generate mature tRNA molecules.
Proteins that bind to RNA molecules. Included here are RIBONUCLEOPROTEINS and other proteins whose function is to bind specifically to RNA.
The process of moving specific RNA molecules from one cellular compartment or region to another by various sorting and transport mechanisms.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
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.
A parasexual process in BACTERIA; ALGAE; FUNGI; and ciliate EUKARYOTA for achieving exchange of chromosome material during fusion of two cells. In bacteria, this is a uni-directional transfer of genetic material; in protozoa it is a bi-directional exchange. In algae and fungi, it is a form of sexual reproduction, with the union of male and female gametes.
The relationships of groups of organisms as reflected by their genetic makeup.
A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
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.
Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.
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.
A modified nucleoside which is present in the first position of the anticodon of tRNA-tyrosine, tRNA-histidine, tRNA-asparagine and tRNA-aspartic acid of many organisms. It is believed to play a role in the regulatory function of tRNA. Nucleoside Q can be further modified to nucleoside Q*, which has a mannose or galactose moiety linked to position 4 of its cyclopentenediol moiety.
An enzyme catalyzing the endonucleolytic cleavage of RNA at the 3'-position of a guanylate residue. EC 3.1.27.3.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Pseudouridine is a modified nucleoside, where the uracil component of a uridine residue in RNA molecules is linked to ribose through a carbon-carbon bond rather than the usual nitrogen-glycosidic bond, which can contribute to structural stability and functional diversity in RNA.
Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
An enzyme that activates aspartic acid with its specific transfer RNA. EC 6.1.1.12.
Proteins that bind to and transfer CHOLESTEROL ESTERS between LIPOPROTEINS such as LOW-DENSITY LIPOPROTEINS and HIGH-DENSITY LIPOPROTEINS.
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.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Methods of implanting a CELL NUCLEUS from a donor cell into an enucleated acceptor cell.
Constituent of the 60S subunit of eukaryotic ribosomes. 28S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
Proteins prepared by recombinant DNA technology.
RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm.
A transfer RNA which is specific for carrying asparagine to sites on the ribosomes in preparation for protein synthesis.
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.
Proteins obtained from ESCHERICHIA COLI.
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.
The functional hereditary units of BACTERIA.
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.
A sulfur-containing essential L-amino acid that is important in many body functions.
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.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
An enzyme that activates isoleucine with its specific transfer RNA. EC 6.1.1.5.
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.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
An essential branched-chain aliphatic amino acid found in many proteins. It is an isomer of LEUCINE. It is important in hemoglobin synthesis and regulation of blood sugar and energy levels.
Surgical procedure by which a tendon is incised at its insertion and placed at an anatomical site distant from the original insertion. The tendon remains attached at the point of origin and takes over the function of a muscle inactivated by trauma or disease.
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)
N(6)-[delta(3)-isopentenyl]adenosine. Isopentenyl derivative of adenosine which is a member of the cytokinin family of plant growth regulators.
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.
Techniques and strategies which include the use of coding sequences and other conventional or radical means to transform or modify cells for the purpose of treating or reversing disease conditions.
The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.
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.
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.
An enzyme that activates phenylalanine with its specific transfer RNA. EC 6.1.1.20.
A species of gram-negative, aerobic, rod-shaped bacteria found in hot springs of neutral to alkaline pH, as well as in hot-water heaters.
A protein found in bacteria and eukaryotic mitochondria which delivers aminoacyl-tRNA's to the A site of the ribosome. The aminoacyl-tRNA is first bound to a complex of elongation factor Tu containing a molecule of bound GTP. The resulting complex is then bound to the 70S initiation complex. Simultaneously the GTP is hydrolyzed and a Tu-GDP complex is released from the 70S ribosome. The Tu-GTP complex is regenerated from the Tu-GDP complex by the Ts elongation factor and GTP.
Constituent of 50S subunit of prokaryotic ribosomes containing about 3200 nucleotides. 23S rRNA is involved in the initiation of polypeptide synthesis.
An enzyme that activates glutamic acid with its specific transfer RNA. EC 6.1.1.17.
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.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
Elements of limited time intervals, contributing to particular results or situations.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
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.
The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
Transport proteins that carry specific substances in the blood or across cell membranes.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
The complete genetic complement contained in a DNA or RNA molecule in a virus.
Use for nucleic acid precursors in general or for which there is no specific heading.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
An enzyme that activates valine with its specific transfer RNA. EC 6.1.1.9
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.
A family of non-enveloped viruses infecting mammals (MASTADENOVIRUS) and birds (AVIADENOVIRUS) or both (ATADENOVIRUS). Infections may be asymptomatic or result in a variety of diseases.
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.
An enzyme that activates lysine with its specific transfer RNA. EC 6.1.1.6.
An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.
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.
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.
An enzyme that activates leucine with its specific transfer RNA. EC 6.1.1.4.
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.
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.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.
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)
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.
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.
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.
A process of GENETIC TRANSLATION, when an amino acid is transferred from its cognate TRANSFER RNA to the lengthening chain of PEPTIDES.
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).
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)
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.
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.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
Complexes of RNA-binding proteins with ribonucleic acids (RNA).
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.
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.
An enzyme that activates tryptophan with its specific transfer RNA. EC 6.1.1.2.
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.
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.
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
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)
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
The sum of the weight of all the atoms in a molecule.
The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.