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 genes encoding the 9 kDa and 4 kDa polypeptides of cytochrome b-559 have been located in pea chloroplast DNA by coupled transcription-translation of cloned restriction fragments of chloroplast DNA in a cell-free extract of Escherichia coli and by nucleotide sequence analysis. The genes (psbE and psbF) are located approximately 1.0 kbp downstream of the gene for cytochrome f and are transcribed in the opposite direction, similar to the arrangement in the chloroplast genomes of other higher plants. Nucleotide sequence analysis of this region revealed four open reading frames encoding hydrophobic proteins of 83 (psbE), 39 (psbF), 38 and 40 amino acid residues, which are co-transcribed as a single major RNA of 1.1 kb. The 5' and 3' ends of this RNA have been located by primer extension and S1 nuclease mapping. The 5' end of the RNA is located 140 bp upstream of the initiating ATG codon of psbE and is preceded by typical chloroplast promoter sequences. The 3' end of the RNA is located approximately 515 bp downstream of the TAA stop codon of psbF close to a stable stem-loop structure.
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PMID:Two small open reading frames are co-transcribed with the pea chloroplast genes for the polypeptides of cytochrome b-559. 276 83

The nucleotide sequence of a 5.1 kilobase-pair fragment from the central portion of the vaccinia virus genome has been determined. Within this region, five complete and two incomplete open reading frames (orfs) are tightly-clustered, tandemly-oriented, and read in the leftward direction. Late mRNA start sites for the five complete orfs and one incomplete orf were determined by S1 nuclease mapping. The two leftmost complete orfs correlated with late polypeptides of 65,000 and 32,000 molecular weight previously mapped to this region. When compared with each other and with sequences present in protein data banks, the five complete orfs showed no significant homology matches amongst themselves or any previously reported sequence. The six putative promoters were aligned with three previously sequenced late gene promoters. While all of the nine are A-T rich, the only apparent consensus sequence is TAA immediately preceeding the initiator ATG. Identification of this tandemly-oriented late gene cluster suggests local organization of the viral genome.
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PMID:A tandemly-oriented late gene cluster within the vaccinia virus genome. 300 3

Analysis of the sequence of cDNA corresponding to mouse thymidylate synthase (5,10-methylenetetrahydrofolate:dUMP C-methyltransferase, EC 2.1.1.45) mRNA revealed that the termination codon TAA was followed immediately by a poly(A) sequence. This raised the possibility that mouse thymidylate synthase mRNA lacks a 3' untranslated region. In the present study, we have further investigated this possibility. DNA corresponding to the 3' end of the thymidylate synthase gene was isolated from a genomic library. The sequence of the genomic DNA was identical to that of the cDNA in the coding region. However, the termination codon was TAG in the genomic sequence rather than TAA, and poly(A) was not present in the genomic DNA. Sequences flanking the site of poly(A) addition were in good agreement with polyadenylylation consensus sequences. S1 nuclease analysis revealed that approximately 80% of the thymidylate synthase mRNA molecules were polyadenylylated at the termination codon. A secondary polyadenylylation site was detected 190-200 nucleotides downstream of the primary site. We conclude that the major species of mouse thymidylate synthase mRNA lacks a 3' untranslated region and that the final A of the termination codon is added by poly(A) polymerase. It appears that a 3' untranslated region is not essential for the accumulation or translation of this mRNA.
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PMID:Mouse thymidylate synthase messenger RNA lacks a 3' untranslated region. 302 94

A vaccinia virus (VV) gene required for DNA replication has been mapped to the left side of the 16-kilobase (kb) VV HindIII D DNA fragment by marker rescue of a DNA- temperature-sensitive mutant, ts17, using cloned fragments of the viral genome. The region of VV DNA containing the ts17 locus (3.6 kb) was sequenced. This nucleotide sequence contains one complete open reading frame (ORF) and two incomplete ORFs reading from left to right. Analysis of this region at early times revealed that transcription from the incomplete upstream ORF terminates coincidentally with the complete ORF encoding the ts17 gene product, which is directly downstream. The predicted proteins encoded by this region correlate well with polypeptides mapped by in vitro translation of hybrid-selected early mRNA. The nucleotide sequences of a 1.3-kb BglII fragment derived from ts17 and from two ts17 revertants were also determined, and the nature of the ts17 mutation was identified. S1 nuclease protection studies were carried out to determine the 5' and 3' ends of the transcripts and to examine the kinetics of expression of the ts17 gene during viral infection. The ts17 transcript is present at both early and late times postinfection, indicating that this gene is constitutively expressed. Surprisingly, the transcriptional start throughout infection occurs at the proposed late regulatory element TAA, which immediately precedes the putative initiation codon ATG. Although the biological activity of the ts17-encoded polypeptide was not identified, it was noted that in ts17-infected cells, expression of a nonlinked VV immediate-early gene (thymidine kinase) was deregulated at the nonpermissive temperature. This result may indicate that the ts17 gene product is functionally required at an early step of the VV replicative cycle.
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PMID:Nucleotide sequence and transcript organization of a region of the vaccinia virus genome which encodes a constitutively expressed gene required for DNA replication. 303 68

The DNA sequence of the gene for the fermentative yeast alcohol dehydrogenase has been determined. The structural gene contains no introns. The amino acid sequence of the protein as determined from the nucleotide sequence disagrees with the published alcohol dehydrogenase isozyme I (ADH-I) sequence for 5 of the 347 amino acid residues. At least one, and perhaps as many as four, of these differences is probably due to ADH-I protein heterogeneity in different yeast strains and not to sequencing errors. S1 nuclease was used to map the 5' and 3' ends of the ADH-I mRNA. There are two discrete, mature 5' ends of the mRNA, mapping 27 and 37 nucleotides upstream of the translation initiating ATG. These two equally prevalent termini are 101 and 91 nucleotides, respectively, downstream from a TATAAA sequence. Analysis of the 3' end of ADH-I mRNA disclosed two minor ends upstream of the major poly(A) addition site. These three ends map 24, 67, and 83 nucleotides, respectively, downstream from the translation-terminating TAA triplet. The sequence AA-TAAG is found 28 to 34 nucleotides upstream of each ADH-I mRNA poly(A) addition site. Sequence comparisons of these three 3' ends with those for four other yeast mRNAs yielded a 13-nucleotide consensus sequence to which TAAATAAGA is central. All of the known yeast poly(A) addition sites map at or near the A residue of a CTA site 25 to 40 nucleotides downstream from this consensus octamer.
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PMID:The primary structure of the Saccharomyces cerevisiae gene for alcohol dehydrogenase. 627 22

Escherichia coli glycyl-tRNA synthetase is one of two aminoacyl-tRNA synthetases which is comprised of two different subunits (in an alpha 2 beta 2 structure). The two coding regions occur in tandem in the order alpha + beta and are synthesized from a single mRNA (Keng, T., Webster, T. A., Sauer, R. T., and Schimmel, P. R. (1982) J. Biol. Chem. 257, 12503-12508). Primary structures of both proteins were determined by DNA sequencing of each coding region and by analysis of tryptic fragments of the enzyme. The alpha-subunit is 303 codons and terminates with TAA; the beta-subunit is 689 codons followed by tandem TAA stops. S1 nuclease mapping of the 3'-end of the two-cistron glyS mRNA showed that it predominantly ends 33/34 bases beyond the tandem stops with an RNA polymerse terminator sequence. Altogether, 43% of the translated polypeptide sequences were confirmed by mass spectrometric analysis of peptide fragments including confirmation of the COOH-terminal end of the beta-chain. This involved determinations, by fast atom bombardment mass spectrometry, of the masses of numerous whole tryptic fragments (with an accuracy of better than 1 Da) and of fragments truncated by one to three cycles of Edman degradations. The primary structures of the two subunits show no homologies with each other and have no internal sequence repeats of significance. While there are no extensive homologies with five other sequenced, or partially sequenced, synthetases, the alpha-subunit has a short sequence which can be aligned with sequences found in functionally important areas of two other synthetases and in uncharacterized parts of a third and fourth synthetase.
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PMID:Primary structures of both subunits of Escherichia coli glycyl-tRNA synthetase. 630 9

Sequences in the 3'-untranslated region of two different octopine T-DNA genes were analyzed with regard to their significance in polyadenylation. Poly(A) addition sites were localized precisely by S1 nuclease mapping with T-DNA-derived mRNAs isolated from tobacco. The gene encoding transcript 7' contains two AATAAA hexanucleotides, respectively 119 bp and 170 bp downstream of the TAA stop codon. A single poly(A) site was mapped 24-25 bp downstream of the first AATAAA. Further, we show that a mutant octopine synthase gene, which has lost part of its 3'-untranslated region by deletion, is still active. This mutant gene terminates 19 bp upstream from the major wild-type polyadenylation site. The deletion also removes the AATAAT signal preceding this site. The mutant octopine synthase gene contains a minimum of four different poly(A) sites. The most prominent of these sites is identical to the minor poly(A) site of the wild-type gene, and is preceded by a sequence AATGAATATA. Three other sites are located within the adjacent plant DNA, giving rise to hybrid T-DNA/plant DNA transcripts. The two most distal sites are probably dependent on a motif AATAAATAAA, found 29 bp away from the T-DNA/plant DNA junction.
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PMID:Identification of sequences involved in the polyadenylation of higher plant nuclear transcripts using Agrobacterium T-DNA genes as models. 1189 58