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 cyc1-512 mutant of the yeast Saccharomyces cerevisiae contains a 38 bp deletion in the 3' untranslated region of the CYC1 gene, resulting in CYC1 mRNAs that are elongated, presumably labile, and reduced to 10% of the normal level. Analysis with S1 nuclease and a novel PCR procedure revealed that the low amount of cyc1-512 mRNA contained many discrete 3' termini at certain sites, ranging from the wild-type position to over 2000 nucleotides (nt) downstream. The cyc1-512 mRNA deficiency was completely or almost completely restored in eight intragenic revertants that contained six different single and multiple base-pair changes within a 300 bp region downstream from the translation terminator codon. Two of the six different reversions formed the sequence TAG...TATGTA, whereas the other four reversions created the sequences TATATA or TACATA. The positions of these revertant sequences varied, even though they caused an increased use of specific major downstream mRNA 3' endpoints, apparently identical to those seen in the cyc1-512 mRNA. However, several revertants contained minor end points not corresponding to any of the cyc1-512 mRNAs. The capacity of these three signals to form 3' ends was confirmed with sequences constructed by site-directed mutagenesis. We therefore suggest that the production of 3' termini of yeast mRNA may involve at least two functionally distinct elements working in concert. One type of element determines the sites of preferred 3' mRNA termini, as represented by the cyc1-512 termini. The second type of element, which includes TAG...TATGTA and TATATA motifs, operates at a distance to enhance the use of the downstream 3' preferred sites.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distinct cis-acting signals enhance 3' endpoint formation of CYC1 mRNA in the yeast Saccharomyces cerevisiae. 184 75

Ten fragments of higher eucaryotic DNA were tested for upstream activation sequence activity in Saccharomyces cerevisiae by inserting them upstream of a CYC1::lacZ promoter lacking an upstream activation sequence. Fragments containing the 21-base-pair repeat region, the enhancer of simian virus 40 or both strongly stimulated beta-galactosidase synthesis, and three fragments from the polyomavirus enhancer region stimulated moderate levels. Three of the four controls of random DNA sequences failed to stimulate significant levels, and the fourth stimulated moderate levels. The stimulation in all cases was independent of the orientation of the inserted fragment. Two series of clones were examined in which between one and six tandemly arranged copies of a fragment were inserted into the XhoI site of the vector. Very interestingly, we detected an apparent exponential relationship between the number of copies of a fragment and the amount of beta-galactosidase produced. Southern analysis showed that increases in enzyme activity were not a result of increased plasmid copy number. Rather, quantitative S1 nuclease analysis demonstrated that the increases were correlated with steady-state levels of lacZ-specific mRNA. We suggest that there may be an evolutionary relationship between some transcriptional activation sequences in yeast cells and the higher eucaryotic regulatory elements that we tested.
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PMID:Enhancer and promoter elements from simian virus 40 and polyomavirus can substitute for an upstream activation sequence in Saccharomyces cerevisiae. 215 86

The 5'-flanking region of the Saccharomyces cerevisiae catalase T gene (CTT1) and the part of the gene coding for the N-terminus of catalase T were sequenced. 5'-Ends of transcripts of the region were located by S1 nuclease mapping and primer extension. To analyse control elements in the upstream region, a CTT1-lacZ gene fusion was constructed. Deletion analysis was carried out within a part of the 5'-flanking region showing homology to the upstream region of the yeast CYC1 gene. Like the CTT1 gene, this gene is controlled by heme, oxygen and glucose. The results obtained show that the CTT1 gene is positively controlled by heme. Tentative evidence has been obtained for the involvement of upstream sequences homologous to UAS1 and UAS2 of the CYC1 gene in heme control. Further, a negative site has been located between the upstream activator sites and the transcription start. Within this negative region a ten base-pair sequence was detected that shows high homology to a sequence located within a negative control region of the CYC1 gene and some homology to the negative control elements of the S. cerevisiae CAR1 and CAR2 genes.
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PMID:Heme control region of the catalase T gene of the yeast Saccharomyces cerevisiae. 242 50

The 5' termini of yeast CYC1 RNA molecules have been mapped, by nuclease S1 digestion of mRNA . DNA duplexes, to seven locations from 29 to 93 base pairs upstream from the initiating ATG codon. When the CYC1 gene is introduced into yeast in plasmid YEp13, substantially the same transcripts are made. Using this system to study in vivo gene expression, we measured the capacity of enzymatically produced DNA deletions to form the normal set of RNAs. Four regions of 5'-flanking DNA were identified as functional. Sequences within the region -242 to -139 are required for maximal CYC1 transcript formation; their deletion reduces transcription by a factor of 15 but does not change the pattern of 5' ends observed. Deletion of the sequence between -242 and -99 does not further change the overall transcript level but does affect the specificity of CYC1 mRNA starting. A deletion that extends from -242 to -75 causes both an additional shift in the pattern of 5' ends observed and a further large decrease (factor of 10--20) in CYC1 RNA level. Deletions that extend from -242 to -43, and particularly two deletions that extend still closer to the initiating ATG, cause the appearance of an abundant transcript which starts upstream of position -1078 and of minor transcripts starting in the region -325 to -245.
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PMID:Deletion mapping of sequences essential for in vivo transcription of the iso-1-cytochrome c gene. 626 71