Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The temperature-sensitive RLA209-15 fetal rat hepatocyte line grown at the nonpermissive temperature (40 degrees C, normal phenotype) produces authentic rat alpha-fetoproteins (AFPs) of 69K and 73K (fetal AFPs) which are encoded by a 2.2-kb mRNA. These cells also produce low levels of a 1.7-kb AFP mRNA and a 65K variant AFP when grown at the permissive temperature (33 degrees C, transformed phenotype). Hybrid-selected translation demonstrates that the 1.7-kb AFP mRNA encodes the 65K variant AFP. Northern blot hybridization and S1 nuclease analyses indicate that the 1.7-kb mRNA lacks sequences present in the first seven 5' exons of the 2.2-kb AFP mRNA. However, the 1.7- and 2.2-kb AFP mRNAs share common sequences extending from the beginning of the eighth exon (corresponding to nucleotide 873 of the fetal AFP mRNA) to the 3' end. Primer extension analysis suggests that the 1.7-kb RNA contains additional sequences 5' to the common regions shared by both AFP mRNAs. We have previously shown that adult rat liver produces a 1.7-kb AFP mRNA; we now report the isolation of a cDNA (ARFP5) encoding this variant AFP mRNA from an adult rat liver cDNA library. Restriction endonuclease mapping and sequence analysis of ARFP5 confirm that the 1.7- and 2.2-kb AFP mRNAs share similar sequences at the 3' region (approximately 1.1 kb). However, ARFP5 contains an additional 90 bp variant AFP mRNA-specific 5' sequence which is located in the seventh intron of the rat AFP gene.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Fetal and variant alpha-fetoproteins are encoded by mRNAs that differ in sequence at the 5' end. 246 1

The adult rat liver contains three alpha-fetoprotein (AFP) mRNAs of 2.2 (minor), 1.7, and 1.5 kb. These transcripts share a common 3' sequence, but the 1.7- and 1.5-kb AFP mRNAs lack sequences present in the first seven 5' exons of the 2.2-kb AFP mRNA. S1 nuclease analysis maps the 1.7-kb mRNA at the 5' boundary of the eighth exon of the 2.2-kb AFP mRNA and the 1.5-kb mRNA in the middle of the eight exon. In a transformed fetal rat liver cell line, we have previously identified a 1.7-kb AFP mRNA which is encoded by an AFP cDNA (ARFP5) isolated from an adult rat liver cDNA library. The 90-bp 5' sequence of ARFP5, which is located in the seventh intron of the rat AFP gene, is not present in the 2.2-kb fetal AFP mRNA, although ARFP5 does contain nucleotide sequence present in the 2.2-kb AFP mRNA extending from the beginning of its eighth exon (nucleotide 873) to the 3' end. The 1.7-kb RNA in adult liver also hybridizes with the 90-bp 5' sequence of ARFP5, suggesting that the two 1.7-kb AFP mRNAs are similar. The developmental profile of these AFP transcripts shows that fetal rat liver contains mainly the 2.2-kb mRNA which decreases to a very low level around the fifth week after birth. The 1.7- and 1.5-kb AFP mRNAs can be visualized about the third and fourth weeks after birth, respectively, and are the major AFP mRNAs in the liver of rats that are older than 4 weeks. The levels of the AFP mRNAs in adult liver are approximately 0.4% of the AFP mRNA level in 18-day-old fetal liver. Both the 1.7- and 1.5-kb AFP mRNAs are actively translated; they direct the cell-free synthesis of two polypeptides of 50K and 44K. A 50K polypeptide is also the encoded product of the 1.7-kb mRNA in the transformed fetal rat liver cell line, suggesting that the 44K polypeptide may be encoded by the 1.5-kb AFP mRNA.
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PMID:Expression of the alpha-fetoprotein gene in adult rat liver. 246 24

We have detected specific endonucleolytic cleavages of mouse albumin mRNA by S1 nuclease protection analysis of total RNA from fetal mouse liver using a cDNA probe spanning the middle, coding region of albumin mRNA. With the use of probe labeled at its 5' end, three prominent cleavages were detected which were confirmed and their endonucleolytic nature was established by further analysis using 3' end-labeled probe. The latter probe also revealed one more cleavage which was not detected with the 5' end-labeled probe. These cleavages mapped to positions on the mRNA which included a unique sequence motif CCAN1-3CUGN0-1UGAU. Degradation intermediates corresponding to these cleavages were consistently observed, specifically in fetal liver but not in normal or regenerating adult liver and appeared to have originated in vivo. Their levels decreased progressively from 18th day of gestation and became undetectable by 20 days after birth. No detectable changes in the levels of any of the prominent degradation products of alpha-fetoprotein (a homologue of albumin) mRNA could be observed during this period of development. Since accumulation of degradation intermediates is known to correlate with higher rate of mRNA turnover, our observations raise the possibility that the stability of albumin mRNA may be lower in fetal than in adult mouse liver.
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PMID:Specific endonucleolytic cleavages of mouse albumin mRNA and their modulation during liver development. 789 85