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 nucleotide sequence of a 2.1 kb DNA fragment bearing the HIS5 gene of Saccharomyces cerevisiae, which encodes histidinol-phosphate aminotransferase (EC 2.6.1.9), has been determined. An open reading frame of 1,152 bp was found. S1 nuclease mapping indicated that the major transcription starts at position -37 from the ATG codon and the minor (approximately 20%) at -34 in both repressive and derepressive conditions. Northern analysis indicated that transcription of the HIS5 gene is under the general control of amino acid biosynthesis. The 5' noncoding region of the gene, thus far examined up to position -616, contains three copies of sequences homologous to the short repeats of the consensus sequence, 5'-AATGTGACTC-3', suggested for general amino acid control in the HIS1, HIS3, HIS4, and TRP5 at positions -336, -275 and -205. The consensus sequence closest to the open reading frame was shown to be necessary but not sufficient for general amino acid control, by examination of beta-galactosidase appearance in S. cerevisiae cells carrying various mutant HIS5 promoter regions fused to the lac'Z gene and inserted at the leu2 locus of chromosome III.
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PMID:Structure of the yeast HIS5 gene responsive to general control of amino acid biosynthesis. 330 7

The HIS1 gene of Saccharomyces cerevisiae encodes ATP phosphoribosyltransferase, the first enzyme in the pathway of histidine biosynthesis. We have cloned this gene by complementation of a his1 auxotroph. The HIS1 coding region was localized within the cloned segment by assay of subcloned fragments for their ability to complement a his1 auxotroph. We determined the DNA sequence of the HIS1 region defined by this complementation test. S1 nuclease and exonuclease VII mapping of the 5' and 3' termini of HIS1 mRNA reveal considerable heterogeneity at both ends of the transcript, especially the 5' end which displays 13 different termini that span a 110-base pair region. Northern analysis shows that derepression of HIS1 enzyme activity under conditions of amino acid deprivation can be accounted for by an increase in the steady state level of HIS1 mRNA. There are no large differences between the relative levels of HIS1 mRNA molecules with different 5' termini in repressed and derepressed cells. In the DNA sequence upstream from the 5' termini of HIS1 mRNA we have found four closely related copies of a 9-base pair sequence. This sequence is also repeated in the 5' noncoding regions of HIS4, HIS3, and TRP5. Closely related sequences are not found flanking a number of other yeast genes, suggesting that the repeated sequence plays a role in the regulation of amino acid biosynthetic genes subject to the general amino acid control.
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PMID:Repeated DNA sequences upstream from HIS1 also occur at several other co-regulated genes in Saccharomyces cerevisiae. 630 Jan 23