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

The rat beta-galactoside alpha 2,6-sialytransferase gene is differentially utilized by liver and kidney in the generation of mRNAs that predict substantially divergent polypeptides. In order to determine the biosynthetic relationship between these sialyltransferase mRNA isoforms, genomic sequences were isolated and analysed. Five exons that span at least 40 kb of DNA carry the coding information for the liver beta-galactoside alpha 2,6-sialyltransferase protein. An additional exon contains only sequences for the 5'-untranslated leader of the liver mRNA. In contrast, the predominant kidney mRNAs from this gene share only three coding exons that specify the carboxyl terminal 42% of the liver sialyltransferase protein sequence. In addition, these kidney mRNAs contain information from two other exons that comprise the 5' divergent region of these transcripts. Primer extension and S1 nuclease protection analysis demonstrate that the hepatic and kidney specific mRNAs are transcriptionally initiated at different sites within the sialyltransferase gene. While the hepatic sialyltransferase mRNAs are transcribed from the first exon, the kidney transcripts are initiated from a site within the third intron. Genomic regions upstream of both transcriptional initiation sites can regulate expression of the bacterial chloramphenicol acetyltransferase gene in transiently transfected L cells. Together, the data implicate multiple promoters as a principle mechanism in the generation of kidney and liver gene product diversity in sialyltransferase expression.
 ...
PMID:Rat beta-galactoside alpha 2,6-sialyltransferase genomic organization: alternate promoters direct the synthesis of liver and kidney transcripts. 198 83

A probe generated from the coding sequence of the rat hepatic beta-galactoside alpha 2,6-sialyltransferase was used to screen a human cDNA library constructed of human submaxillary gland mRNA lambda gt-11. We report the isolation and characterization of a human cDNA, HSM-ST1, that is putatively the human homolog of the beta-galactoside alpha 2,6-sialyltransferase. The largest human clone contains a 1.3 kb cDNA insert and is predicted to encompass 75% of the coding sequence as well as a small portion of the 3' untranslated region. Comparative analysis of this insert with the rat hepatic alpha 2,6-sialyltransferase sequence indicates 79% nucleotide similarity between the two sequences in the predicted coding region. On the amino acid level, the degree of conservation is 86%. Substantial sequence similarity is observed in the 3'-untranslated region between the rat and human sequences as well. S1 nuclease analysis was performed to demonstrate the expression of HSM-ST1 transcripts in the human hepatoma cell line, HepG2, and in the human colonic adenocarcinoma cell lines, LS174T.
 ...
PMID:Isolation and characterization of a partial cDNA for a human sialyltransferase. 280 95

A single human gene, SIAT1, encodes the beta-galactoside alpha 2,6-sialyltransferase from which multiple mRNA isoforms are generated. In rat, expression of the hepatic mRNA isoform (Form 1) has been defined with respect to the transcriptional initiation site and promoter region. We show here that a similar hepatic SIAT1 mRNA isoform exists in human. Another human mRNA isoform, a mature B-cell-specific mRNA isoform (Form 2), was previously reported. Here, we used 5'-RACE and S1 nuclease protection analysis to define the 5'-untranslated region of Form 2 human SIAT1 mRNA. We demonstrate conclusively that Form 2 mRNA is initiated from a point completely distinct from that of Form 1 mRNA. A number of cis-acting regulatory elements residing immediately 5'of the Form 2 initiation site includes AP-1, AP-2, NF-kappa B, NF-IL6, C/EBP, and CREB. A TATAA box is also present 29 bp 5' of the transcriptional initiation site. CAT reporter gene expression from serially-truncated segments of the 5'-flanking region of the Form 2 initiation site indicates that the segment between -784 and +125 was sufficient to promote high level CAT expression in Louckes, a mature B-cell line. The 5'-flanking region to the human Form 1 initiation site is competent in expression of CAT upon transfection of the fusion construct into HepG2, a human hepatoma cell line. Cellular specificity of expression is apparently retained. Louckes cells expressed CAT efficiently from Form 2 promoter but only marginally from the Form 1 promoter. In contrast, CAT expression from Form 1 promoter is more efficient than from the Form 2 promoter in HepG2 cells.
 ...
PMID:Transcription of the beta-galactoside alpha 2,6-sialyltransferase gene in B lymphocytes is directed by a separate and distinct promoter. 872 35