| ribonucleoproteins, small nuclear | Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm. The u3 snrnp is localised in the nucleolus, where it aligns into base pairs with the 28s rrna precursor in a still unidentified region and functions in pre-rrna processing. The u7 snrnp aligns into base pairs with a conserved sequence in the 3'-end of histone pre-mRNA and is an essential cofactor for the cleavage that creates the mature nonadenylated 3'-end. (12 Dec 1998) |
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| 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, nuclear | RNA molecules found in the nucleus either associated with chromosomes or in the nucleoplasm. (12 Dec 1998) |
| RNA, small nuclear | Short chains of RNA found in the nucleus. Their function is to remove the introns (nontranslated intervening sequences) from mRNA precursors, thereby bringing the two exons (coding segments) together into correct juxtaposition for enzymatic splicing at the correct point. The resulting mRNA is now ready to leave the nucleus. (12 Dec 1998) |
| rod nuclear cell | <pathology> Immature neutrophils released from the bone marrow reserve in response to acute demand. (18 Nov 1997) |
| cistern of nuclear envelope | The space between the internal and external membranes of the nuclear envelope; may be continuous in places with cisterns of the endoplasmic reticulum. Synonym: cistern of nuclear envelope, perinuclear space. (05 Mar 2000) |
| proliferating cell nuclear antigen | Acidic nuclear protein (33 kD) highly expressed in dividing cells. Interacts with D type cyclins. (18 Nov 1997) |
| heterogeneous nuclear 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) |
| heterogenous nuclear RNA | <molecular biology> Originally identified as a class of RNA, found in the nucleus but not the nucleolus, which is rapidly labelled and with a very wide range of sizes, 2-40 kilobases. It represents the primary transcripts of RNA polymerase II and includes precursors of all messenger RNAs from which introns are removed by splicing. (18 Nov 1997) |
| small nuclear 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) |
| nuclear | <cell biology> Of or pertaining to a nucleus; as, the nuclear spindle or the nuclear fibrils of a cell; the nuclear part of a comet, etc. Source: Websters Dictionary (01 Mar 1998) |
| Nuclear actin binding protein | <molecular biology> Nuclear protein, dimer of 34 kD subunits. Binds actin with Kd of around 25M. (18 Nov 1997) |
| nuclear atom | <physics, radiobiology> A concept or model of the atom characterised by the presence of a small, massive nucleus at its centre. (05 Mar 2000) |
| nuclear bag | <cell biology> The aggregation of nuclei occurring in the nonstriated centre of an intrafusal muscle fibre of a neuromuscular spindle. (05 Mar 2000) |
| nuclear bag fibre | The largest type of intrafusal muscle fibre's in a neuromuscular spindle, containing a central aggregation of nuclei (nuclear bag). (05 Mar 2000) |