| loop of henle | A u-shaped turn in the medullary portion of a renal tubule, with a descending limb from the proximal convoluted tubule and an ascending limb to the distal convoluted tubule. (12 Dec 1998) |
|---|---|
| loop of hypoglossal nerve | A loop in the cervical plexus consisting of fibres from the first three cervical nerves. Fibres from a loop between the C-1 and C-2 spinal nerves accompany the hypoglossal nerve for a short distance, leaving it as the superior root of the ansa cervicalis. Fibres from a loop between the C-2 and C-3 spinal nerves form the inferior root of the ansa cervicalis. Most commonly, the roots merge, forming the ansa cervicalis, which gives rise to branches innervating infrahyoid muscles. Synonym: cervical loop, loop of hypoglossal nerve. (05 Mar 2000) |
| loop resection | A diagnostic and therapeutic gynecological surgical technique for removing dysplastic cells from the cervix. In this office procedure conducted with the aid of colposcopy, a small wire loop is used to excise visible patches of cervical intraepithelial neoplasia. Like cauterization, cryosurgery, and CO2 laser procedures, loop excision can be done with local anaesthetic, and is an uncomplicated, relatively inexpensive way of removing dysplastic cells; in addition, it provides material for biopsy. It is not advised for cases of severe dysplasia or carcinoma in situ, which are better addressed by cervical conization, an inpatient procedure. Synonym: loop resection. (05 Mar 2000) |
| acceptor RNA | rNA |
| antisense RNA | <molecular biology> A complementary RNA sequence that binds to (and thus blocks the transcription of) a naturally-occuring (sense) messenger RNA molecule. These proteins can be used to selectively turn off production of certain proteins or block viral genetic instructions, by marking them for destruction by cellular enzymes, in order to prevent the building of new virus or the infection of new cells. (09 Oct 1997) |
| bacteriophage T3 RNA polymerase | <enzyme> Used for the rapid generation of strand-specific RNA molecules that can be used for the identification of genes in hybridization experiments Registry number: EC 2.7.7.- Synonym: t3 RNA polymerase (26 Jun 1999) |
| cap II RNA(nucleoside-2'-)methyltransferase | <enzyme> Converts cap i-terminated mRNA to cap II-terminated mRNA Registry number: EC 2.1.1.- Synonym: cap II methylase (26 Jun 1999) |
| cap I RNA (nucleoside-2'-)methyltransferase | <enzyme> Converts cap 0-terminated mRNA to cap i-terminated mRNA Registry number: EC 2.1.1.- Synonym: cap I methylase (26 Jun 1999) |
| p68 RNA helicase | <enzyme> An RNA helicase isolated from uv-induced tumours in mice; amino acid sequence has been determined Registry number: EC 2.7.7.- Synonym: dead box helicase p68 (26 Jun 1999) |
| masked messenger RNA | <molecular biology> Long lived and stable mRNA found originally in the oocytes of echinoderms and constituting a store of maternal information for protein synthesis that is unmasked (derepressed) during the early stages of morphogenesis. In these early stages the rate of cell division is so rapid that transcription from the embryonic genome cannot occur. Undoubtedly not restricted to oocytes and the term can be applied to any mRNA which is present in inactive form. (18 Nov 1997) |
| ribosomal RNA | <molecular biology> A nucleic acid found in all living cells. Plays a role in transferring information from DNA to the protein-forming system of the cell. (16 Dec 1997) |
| messenger-like RNA | An ill-defined form of RNA, of high molecular weight, that never leaves the nucleus and is thought to be the precursor of messenger RNA. (05 Mar 2000) |
| messenger RNA | <molecular biology> Single stranded RNA molecule that specifies the amino acid sequence of one or more polypeptide chains. This information is translated during protein synthesis when ribosomes bind to the mRNA. In prokaryotes, mRNA is normally formed by splicing a large primary transcript from a DNA sequence and protein synthesis starts while the mRNA is still being synthesised. Prokaryote mRNAs are usually very short lived (average t 1/2 is 5mins.). In contrast, in eukaryotes the primary transcripts (HnRNA) are synthesised in the nucleus and they are extensively processed to give the mRNA that is exported to the cytoplasm where protein synthesis takes place. This processing includes the addition of a 5' 5' linked 7 methyl guanylate cap at the 5' end and a sequence of adenylate groups at the 3' end, the poly A tail, as well as the removal of any introns and the splicing together of exons, only 10% of HnRNA leaves the nucleus. Eukaryote mRNAs are comparatively long lived with a half life ranging from 30minutes to 24 hours. (27 Jun 1999) |
| GTP-RNA guanylyltransferase | <enzyme> Catalyses addition of GMP residue to 3'-ends of oligonucleotide primers Registry number: EC 2.7.7.- Synonym: terminal guanylyltransferase (26 Jun 1999) |
| RNA | <molecular biology> A nucleic acid found in all living cells. Plays a role in transferring information from DNA to the protein-forming system of the cell. (16 Dec 1997) |