Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.31.1 (micrococcal nuclease)
 2,818 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

SV40 early pre-mRNA is alternatively spliced by utilization of two different 5' splice sites and a shared 3' splice site to produce large T and small t mRNAs. The ratio of small t to large T mRNAs produced in human embryonic kidney 293 cells is 10- to 20-fold greater than in other mammalian cells, suggesting the existence of a 293 cell-specific factor that modulates alternative splicing. Here we show that nuclear extracts from 293 cells give rise to significantly more small t splicing than do extracts from HeLa cells. Using an in vitro complementation assay, we have characterized and extensively purified a factor from 293 extracts that brings about striking increases in small t splicing with concomitant decreases in large T splicing. The factor is heat sensitive and micrococcal nuclease resistant, suggesting that it is a protein lacking an accessible RNA component. Purification of the alternative splicing factor indicates that the activity is contained in one of several possibly related polypeptides of 30-35 kd.
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PMID:A protein factor, ASF, controls cell-specific alternative splicing of SV40 early pre-mRNA in vitro. 216 68

We cloned complementary DNAs for 4SNc-Tudor protein (SN4TDR) from yellowtail (Seriola quinqueradiata), torafugu (Takifugu rubripes), and zebrafish (Danio rerio). This protein contains 4 staphylococcal nuclease domains at the N terminus followed by a Tudor domain. We also identified the 4SNc-Tudor proteins highly homologous to that in yellowtail from the Takifugu genomic database. According to the smart database, these fish proteins had an overlapping Tudor domain (smart00333) with a complete 5 SNc domain (smart00318). In addition, 2 possible translation start sites were observed at the 5' sequences in all 3 fish species. Northern blot analysis of different yellowtail organs showed that the full SN4TDR messenger RNA was approximately 4000 nucleotides long and that its expression was highest in liver and gallbladder, being about 2 to 5 times higher than in kidney, brain, ovary, and gills, and exceedingly low in spleen, heart, and muscle. A minor 2000-nucleotide transcript observed in kidney, spleen, and gallbladder, was attributable to an alternatively spliced variant of this gene. Total proteins extracted from yellowtail liver were fractionated by heparin affinity column chromatography and separated by sodium dodecylsulfate polyacrylamide gel electrophoresis. Analyses by SDS-PAGE and liquid chromatography with tandem mass spectroscopy identified the polypeptide encoded by SN4TDR as a single molecule of 102 kDa.
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PMID:Structural analysis of cDNAs coding for 4SNc-Tudor domain protein from fish and their expression in yellowtail organs. 1613 64