| 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) |
| RNA, plant | Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis. (12 Dec 1998) |
| RNA plasmid | <molecular biology> DsRNA found in yeasts, also called killer factors. Their nomenclature is uncertain and some scientists consider them viruses. (23 Aug 1998) |
| RNA precursors | RNA copies from DNA that exactly represent the genome sequence. This RNA cannot be used for producing protein until RNA splicing takes place. During this procedure the phosphodiester bonds at exon-intron boundaries are cleaved and the intron is excised. Consequently a new bond is formed between the ends of the exons. The resulting RNA is mature RNA which can be translated into protein. (12 Dec 1998) |
| RNA primase | <enzyme, molecular biology> An RNA polymerase that synthesises a short RNA primer sequence to initiate DNA replication. (18 Nov 1997) |
| RNA primer | <molecular biology> The primer sequence synthesised by RNA primase. (23 Aug 1998) |
| RNA probes | RNA, usually prepared by transcription from cloned DNA, which complements a specific mRNA or DNA and is generally used for studies of virus genes, distribution of specific RNA in tissues and cells, integration of viral DNA into genomes, transcription, etc. Whereas DNA probes are preferred for use at a more macroscopic level for detection of the presence of DNA/RNA from specific species or subspecies, RNA probes are preferred for genetic studies. Conventional labels for the RNA probe include radioisotope labels 32p and 125i and the chemical label biotin. RNA probes may be further divided by category into plus-sense RNA probes, minus-sense RNA probes, and antisense RNA probes. (12 Dec 1998) |
| RNA processing | <molecular biology> Modifications of primary RNA trancripts including splicing, cleavage, base modification, capping and the addition of poly A tails. See: RNA editing. (23 Aug 1998) |