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Definition
 
enEnglish
Ribonucleases definition: Enzymes that catalyze the hydrolysis of ester bonds within RNA. EC 3.1.-.
Ribonuclease definition: Enzymes that catalyze the hydrolysis of RNA
RNA definition: ribonucleic acid; 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.
RNA definition: 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 definition: One of the two types of nucleic acids found in all cells. The other is deoxyribonucleic acid (DNA). RNA transmits genetic information from DNA to proteins produced by the cell.
Ribonucleic Acid definition: A nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules. They play crucial roles in protein synthesis and other cell activities. (MedicineNet.com)
RNA Caps definition: 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.
RNA Nucleotidyltransferases definition: Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. EC 2.7.7.-.
RNA Phages definition: Bacteriophages whose genetic material is RNA, which is single-stranded in all except the Pseudomonas phage phi 6 (BACTERIOPHAGE PHI 6). All RNA phages infect their host bacteria via the host's surface pili. Some frequently encountered RNA phages are: BF23, F2, R17, fr, PhiCb5, PhiCb12r, PhiCb8r, PhiCb23r, 7s, PP7, Q beta phage, MS2 phage, and BACTERIOPHAGE PHI 6.
RNA Polymerase I definition: 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 Replicase definition: An enzyme that catalyses RNA-template-directed extension of the 3'- end of an RNA strand by one nucleotide at a time, and can initiate a chain de novo. (Enzyme Nomenclature, 1992, p293)
RNA-Directed RNA Polymerase definition: An enzyme that catalyzes the template-directed addition of ribonucleotides to the 3' end of a growing RNA chain. The enzyme utilizes single-stranded RNA as a template.
RNA, Bacterial definition: Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
bacterial RNA definition: ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.
RNA, Fungal definition: Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.
RNA, Messenger definition: 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.
messenger RNA definition: RNA sequences that serve as templates for protein synthesis; eukaryotic messenger RNA is synthesized in the nucleus and must be exported to the cytoplasm for translation.
Messenger RNA definition: A class of RNA molecule containing protein-coding information in its nucleotide sequence that can be translated into the amino acid sequence of a protein.
RNA, Neoplasm definition: RNA present in neoplastic tissue.
RNA, Nuclear definition: RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm.
RNA, Ribosomal, 18S definition: Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
18S Ribosomal RNA definition: The second largest of the three RNA components of the mammalian ribosome.
RNA, Ribosomal, 28S definition: Constituent of the 60S subunit of eukaryotic ribosomes. 28S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
28S Ribosomal RNA definition: The largest of the three RNA components of the mammalian ribosome.
tRNA Methyltransferases definition: Enzymes that catalyze the S-adenosyl-L-methionine-dependent methylation of ribonucleotide bases within a transfer RNA molecule. EC 2.1.1.
tRNA Methyltransferase definition: An enzyme that catalyzes the methylation of transfer RNAs.
RNA, Complementary definition: 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)
complementary RNA definition: single-stranded RNA whose base sequence is complementary to specific DNA sequences (e.g., genes) or, more rarely, another single- stranded RNA; usually conveys an artificial hybridization probe or antisense genetic inhibitor.
RNA, Antisense definition: 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, Catalytic definition: 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.
ribozyme definition: catalytic macromolecules, frequently autohydrolytic, composed of RNA.
Ribozyme definition: RNA that contains an intron sequence which has an enzyme-like catalytic activity. This intron sequence has been shown to fold up to form a complex surface that can function like an enzyme in reactions with other RNA molecules and thus synthesize new molecules even in the absence of protein. Synthetic ribozymes can be engineered to specifically cleave a target RNA sequence causing expression down regulation.
RNA, Guide definition: 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 Helicases definition: A family of proteins that promote unwinding of RNA during splicing and translation. EC 2.7.7.-.
RNA Helicase definition: A family of hydrolases that use ATP to catalyze the denaturation of RNA-containing nucleic acid structures.
Ribosome Inactivating Proteins definition: N-Glycosidases that remove adenines from RIBOSOMAL RNA, depurinating the conserved alpha-sarcin loop of 28S RIBOSOMAL RNA. They often consist of a toxic A subunit and a binding lectin B subunit. They may be considered as PROTEIN SYNTHESIS INHIBITORS. They are found in many PLANTS and have cytotoxic and antiviral activity.
RNA Editing definition: 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).
RNA, Helminth definition: Ribonucleic acid in helminths having regulatory and catalytic roles as well as involvement in protein synthesis.
RNA, Chloroplast definition: Ribonucleic acid in chloroplasts having regulatory and catalytic roles as well as involvement in protein synthesis.
RNA, Archaeal definition: Ribonucleic acid in archaea having regulatory and catalytic roles as well as involvement in protein synthesis.
RNA, Untranslated definition: 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 they are not included here.
MicroRNAs definition: Small double-stranded, non-protein coding RNAs, 21-25 nucleotides in length generated from single-stranded microRNA gene transcripts by the same RIBONUCLEASE III, Dicer, that produces small interfering RNAs (RNA, SMALL INTERFERING). They become part of the RNA-INDUCED SILENCING COMPLEX and repress the translation (TRANSLATION, GENETIC) of target RNA by binding to homologous 3'UTR region as an imperfect match. The small temporal RNAs (stRNAs), let-7 and lin-4, from C. elegans, are the first 2 miRNAs discovered, and are from a class of miRNAs involved in developmental timing.
MicroRNA definition: A sequence of single-stranded RNA which is typically 20-25 nucleotides in length and may regulate the expression of other genes. miRNAs are RNA genes which are transcribed from DNA, but are not translated into proteins.
microRNA definition: small regulatory antisense RNA that represses the genetic translation of homologous target RNA; process by which they are generated is related to the process that produces small interfering RNA.
RNA interference definition: The process by which double-stranded RNAs silence cognate genes. Involves posttranscriptional gene inactivation ('silencing') both of transgenes or dsRNA introduced into a germline, and of the host gene(s) homologous to the transgenes or dsRNA. This silencing is triggered by the introduction of transgenes or double-stranded RNA (dsRNA), and occurs through a specific decrease in the level of mRNA of both host genes and transgenes. [GOC:ems, PMID:11201747, PMID:11713190]
posttranscriptional gene silencing definition: The inactivation of gene expression by a posttranscriptional mechanism. [GOC:mah, PMID:15020054]
RNA Interference definition: 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 interference definition: gene silencing phenomenon or technique whereby specific double stranded RNAs trigger degradation of the homologous mRNA; the specific double stranded RNAs are processed into small interfering RNAs which serve as a guide for cleavage of the homologous mRNA in the RNA induced silencing complex.
RNA Interference definition: Sequence-specific posttranscriptional gene silencing. It is mediated by 21- and 22-nucleotide small interfering RNAs (siRNAs) generated by ribonuclease III cleavage from longer dsRNAs.
RNA catabolic process definition: The chemical reactions and pathways resulting in the breakdown of RNA, ribonucleic acid, one of the two main type of nucleic acid, consisting of a long, unbranched macromolecule formed from ribonucleotides joined in 3',5'-phosphodiester linkage. [ISBN:0198506732 "Oxford Dictionary of Biochemistry and Molecular Biology"]
RNA Degradation definition: RNA degradation is a regulated cellular biochemical process that involves depolymerization of RNA macromolecules, which affects the RNA content of cells and regulates gene expression.
antisense RNA definition: OBSOLETE (was not defined before being made obsolete). [GOC:mah]
RNA definition: OBSOLETE (was not defined before being made obsolete). [GOC:ai]
Functional RNA definition: The product of so-called RNA genes; a functional RNA represents the final product of a gene rather than a transient molecule that will be translated into protein.
RNA, Algal definition: Ribonucleic acid in ALGAE having regulatory and catalytic roles as well as involvement in protein synthesis.
 
 
deGerman
RNS definition: [1] Abkürzung für 'R'ibo'n'uklein's'äure
 
frFrench
ADSL definition: Technologie de communication haut débit permettant d’utiliser les lignes téléphoniques déjà existantes afin d’accéder à Internet et d’autres services.