| RNA-directed DNA polymerase | <enzyme> An enzyme that synthesises DNA on an RNA template. It is encoded by the pol gene of retroviruses and by certain retrovirus-like elements. Chemical name: Deoxynucleotide-triphosphate:DNA deoxynucleotidyltransferase (RNA-directed) Registry number: EC 2.7.7.49 (12 Dec 1998) |
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| 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. (12 Dec 1998) |
| RNA editing | <molecular biology> Specific alterations of RNAs, for example C_V changes that are not coded for in the genes. (23 Aug 1998) |
| RNA enzyme | <molecular biology> Often referred to as RNA with catalytic capacity, an enzyme made of nucleic acid not protein that catalyse chemical reactions, often the breakdown of other RNAs. Of particular interest because of the implications for self replicating systems in the earliest stages of the evolution of (terrestrial) life. Their discovery in the mid-1980s refuted the concept that only proteins could be biological catalysts. There is potential for their use as pharmaceuticals and industrial catalysts. (13 Nov 1997) |
| RNA, fungal | Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| 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. (12 Dec 1998) |
| RNA helicase | <enzyme> Nuclear envelope-associated RNA helicase activity in nucleocytoplasmic RNA transport; both glh-1 and glh-2 contain cchc-type zinc fingers; xp54 is xenopus homologue of human RNA helicase p54 Registry number: EC 2.7.7.- Synonym: RNA duplex unwindase, p54 gene product, bat1 gene product, RNA helicase a, rok1 protein, human RNA helicase 1, hrh1 protein, mrdb protein, glh-1 protein, glh-2 protein, RNA helicase p54, xp54, u5 snrnp-specific 100-kD protein (26 Jun 1999) |
| RNA, helminth | Ribonucleic acid in helminths having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA, heterogeneous nuclear | Nuclear nonribosomal RNA larger than about 1000 nucleotides, the mass of which is rapidly synthesised and degraded within the cell nucleus. Some heterogeneous nuclear RNA may be a precursor to mRNA. However, the great bulk of total hnrna hybridises with nuclear DNA rather than with mRNA. (12 Dec 1998) |
| RNA life | <biology, molecular biology> A hypothetical life form lacking DNA and protein which may have existed on early earth and in which RNA served both a genetic coding and a catalytic function. (23 Aug 1998) |
| RNA ligase | <enzyme> An enzyme that catalyses the conversion of linear RNA to a circular form by the transfer of the 5'-phosphate to the 3'-hydroxyl terminus. It also catalyses the covalent joining of two polyribonucleotides in phosphodiester linkage. Chemical name: Poly(ribonucleotide):poly(ribonucleotide)ligase (AMP-forming) Registry number: EC 6.5.1.3 (12 Dec 1998) |
| RNA N-glycosidase | <enzyme> Catalyses hydrolysis of a single adenosine glycosidic bond; probable cause of toxic effect of vero toxin from E coli by inactivating 60s ribosomal subunit Registry number: EC 3.2.2.- Synonym: RNA glycosylase (26 Jun 1999) |
| RNA, nuclear | RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm. (12 Dec 1998) |
| RNA nucleotidyltransferases | <enzyme> Enzymes that catalyze the template-directed incorporation of ribonucleotides into an RNA chain. Registry number: EC 2.7.7. (12 Dec 1998) |
| RNA phages | Bacteriophages whose genetic material is RNA, which is single-stranded in all except the pseudomonas phage phi6. All RNA phages infect their host bacteria via the host's surface pili. Some frequently encountered RNA phages are: qbeta, ms2, bf23, f2, r17, fr, mu2, phicb5, phicb12r, phicb8r, phicb23r, 7s, phi6, pp7. (12 Dec 1998) |