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 small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) in the French bean Phaseolus vulgaris L. is encoded by a small gene family consisting of a minimum of three members. Three small subunit genes (rbcS genes) represented in a light-grown primary leaf cDNA library were characterised by sequencing two cDNAs which were full-length and one which was deficient in part of the sequence encoding the transit peptide. The cDNA clones are identical in their coding sequences, for both the transit peptide and the mature polypeptide, but divergent in their untranslated sequences. The derived amino acid sequence is very similar to that reported for other species, although the first amino acid of the mature polypeptide is isoleucine, which differs from the methionine found in all other higher plant rbcS genes. Surprisingly, one of the cDNA clones contains two introns, which are at positions conserved in rbcS genes from other species. It is concluded that this cDNA resulted from the cloning of an unprocessed transcript. Alternative polyadenylation sites are found for two of the genes. Expression of the rbcS genes in the primary leaves is stimulated by light, although transcripts can readily be detected in dark-grown leaves. Expression is also organ-specific, as in other species. The frequency of cDNA clones in the library indicates that the different genes show quantitative differences in expression and S1 nuclease analysis suggests that individual rbcS genes are photoregulated.
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PMID:Genes encoding the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase in Phaseolus vulgaris L.: nucleotide sequence of cDNA clones and initial studies of expression. 153 29

Five of the genes for the biosynthesis of isoleucine and valine form the ilvGMEDA operon of Escherichia coli K-12. Expression of the operon responds to changes in the availability of isoleucine, leucine, and valine (ILV). Addition of an excess of all three amino acids results in reduced expression of the operon, whereas limitation for one of the three amino acids causes an increase in expression. The operon is preceded by a leader-attenuator which clearly regulates the increased expression that occurs due to reduced aminoacylation of tRNA. To assess the factors that result in the reduced expression of this operon upon the addition of ILV, a series of plasmids were constructed in which the ilv regulatory region was fused to galK. In response to addition of the amino acids, expression of the galK gene fused to the leader-attenuator decreased five- to sevenfold, instead of the twofold observed for the chromosomal operon. A deletion analysis with these plasmids indicated that the ILV-specific decrease in expression required an intact leader-attenuator but not ilvGp2 or the DNA that precedes this promoter. This conclusion was supported by both S1 nuclease analysis of transcription initiation and determination of galK mRNA levels by RNA-RNA hybridization.
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PMID:Analysis of regulation of the ilvGMEDA operon by using leader-attenuator-galK gene fusions. 218 12

The +1 site for transcription initiation of the inducible 23 S rRNA adenine methylase encoded by plasmid pE194 was determined experimentally by nuclease S1 mapping of mRNA synthesized in vivo, and by nuclease T1 mapping of (5'-gamma-32P)-end-labeled transcripts synthesized in vitro. By partial digestion of the in vitro transcripts using S1 and cobra venom nuclease as probes of mRNA conformation, the analysis was extended to reveal single-stranded and double-stranded regions, respectively, which correspond to the critical stems and loops postulated for active and inactive conformations of the nascent mRNA. According to the model for induction, the transition from inactive to active conformation involves disruption of mRNA secondary structure which, in turn, is predicated on protracted occupancy by ribosomes complexed with erythromycin of one of the critical stem sequences. Ribosome occupancy of the critical stem sequence is due to the presence of an open reading frame that encodes part of a 19 amino acid residue "leader" peptide. The existence of this peptide, deduced from the nucleotide sequence of the control region upstream from the methylase structural gene, was demonstrated in vivo as part of a translational fusion with Escherichia coli beta-galactosidase in which the first four amino acid residues of the N-terminal sequence of the fusion protein, analyzed directly by the microsequencing method, were found to comprise N-terminal amino acids 2 through 5, Gly-Ile-Phe-Ser, predicted for the leader peptide.
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PMID:Messenger RNA from Staphylococcus aureus that specifies macrolide-lincosamide-streptogramin resistance. Demonstration of its conformations and of the leader peptide it encodes. 241 56

We have examined transcriptional start sites responsible for expression of the transposase and transposition inhibitor proteins encoded by IS50R, and determined the likely translational start site of transposase. Amino-terminal analysis of a transposase-beta-galactosidase fusion protein gave the sequence Met-Ile-Thr-Ser-Ala, which corresponds to the predicted amino acid sequence starting at position 93 of IS50. S1 nuclease mapping of IS50 RNA produced in vivo indicated that three transcripts, T1, T2 and T3, start near this position. Only T1 starts upstream from the transposase amino terminus. T2 corresponds to an in-vitro transcript described previously. Analysis of the transcripts and proteins produced from deletion derivatives of an IS50-lacZ construct suggested that the three transcripts initiate at independent but overlapping promoters clustered near the end of IS50. This analysis confirmed that only T1 can encode transposase, and that T2 is largely responsible for expression of the inhibitor protein. The coding capacity of T3 was not determined. Finally, transcripts that originate outside of IS50 are prevented from expressing transposase because of a secondary structure that is present in these transcripts only.
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PMID:Transcriptional and translational initiation sites of IS50. Control of transposase and inhibitor expression. 243 19

The ilvC gene of Escherichia coli K12 encodes acetohydroxy acid isomeroreductase, the second enzyme in the parallel isoleucine-valine biosynthetic pathway. Previous data have shown that transcription of the ilvC gene is induced by the acetohydroxy acid isomeroreductase substrates, acetohydroxybutyrate or acetolactate, and that this substrate induction of ilvC expression is mediated by a positive activator encoded by the ilvY gene. We report here the isolation and complete nucleotide sequence of the ilvY and ilvC genes. The ilvY and ilvC genes encode polypeptides of Mr 33,200 and 54,000, respectively. In vitro transcription-translation of these gene templates results in the synthesis of gene products of these identical molecular weights. The ilvC gene is transcribed in the same direction as the genes of the adjacent ilvGMEDA operon. The ilvY gene is transcribed in a direction opposite to the ilvC and ilvGMEDA genes. The in vivo transcriptional initiation sites of the ilvY and ilvC genes have been determined by S1 nuclease protection experiments. These transcriptional initiation sites are 45 nucleotides apart, and transcription of the ilvY and ilvC genes is initiated via divergent overlapping promoters. The nucleotide sequence of the ilvY and ilvC promoters and 5'-coding regions of Salmonella typhimurium LT2 have been determined. A comparison of these sequences with E. coli K12 suggests regions important in the promotion, regulation, and translation of the ilvY and ilvC genes. A model is presented in which the ilvY-encoded activator binds to an operator site in the overlapping promoter region and reciprocally regulates the transcription of the ilvY and ilvC genes. The carboxyl-terminal amino acid sequence of threonine deaminase encoded by the ilvA gene of the ilv-GMEDA operon of E. coli K12 has been identified by homology with the previously deduced threonine deaminase amino acid sequence encoded by the ilv1 gene of Saccharomyces cerevisiae. Based on the deduced amino acid sequences of the ilvA and ilvY genes, the translational termination codons for both genes are shown to be separated by 52 nucleotides. The proximity of the ilvA and ilvY genes suggests that the 3'-ends of these transcripts overlap.
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PMID:Nucleotide sequence and in vivo expression of the ilvY and ilvC genes in Escherichia coli K12. Transcription from divergent overlapping promoters. 300 15

Expression of 5 yeast mitochondrial tRNA genes (Ala, Ile, Tyr, Asn and Metm), localized upstream from the oxil gene has been analyzed by in vitro capping using guanylyltransferase, northern hybridization and S1 nuclease mapping in the wild type and a rho-strain. The 5 tRNA sequences belong to the same transcriptional unit which is initiated 133 bp upstream from the tRNA(Ala) gene at a promoter sequence TTATAAGTA. Furthermore, a truncated tRNA(Tyr) transcript, 2 nucleotides shorter than mature tRNA(Tyr) has been found, only in the rho-strain. This minor transcript may result from secondary transcription initiation at a variant nonanucleotide sequence, ATATAAGGA, which overlaps the tRNA(Tyr) coding sequence by 3 nucleotides. The polycistronic precursor has proven to be useful in investigation of the mechanisms of tRNA processing. Maturation of this primary transcript proceeds exclusively by precise endonucleolytic cleavages at the 5' and 3'-ends of tRNA sequences.
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PMID:Transcription initiation and RNA processing of a yeast mitochondrial tRNA gene cluster. 330 93

The Ile repressor protein negatively controls expression from the ilv and thr promoters of Escherichia coli K12. Its existence was inferred from an analysis of the phenotypes of the ileR mutant avr-16 (Johnson, D. I., and Somerville, R. L. (1983) J. Bacteriol. 155, 49-55). The nucleotide sequence of ileR, the structural gene for Ile repressor, has been determined. A DNA segment of 300 base pairs constitutes the ileR gene. The predicted gene product, a protein of 100 amino acids (molecular weight 11,823) has primary structural features reminiscent of other double-stranded DNA-binding regulatory proteins. S1 nuclease mapping of the 5' terminus of ileR mRNA revealed two discrete species whose startpoints differed by approximately 47 nucleotides. The ileR gene, like other repressors for amino acid biosynthetic systems, is autogenously regulated at the transcriptional level. Within the ileR promoter region lie two 18-base pair segments of DNA bearing significant homology to putative operator targets also found within the thr and ilv promoters. A second open reading frame capable of specifying a protein of 83 amino acids, designated orf83, is transcribed divergently from the ileR gene. There are 202 base pairs separating the first codons of the two genes. S1 nuclease mapping of the 5' terminus of orf83 mRNA revealed two discrete species whose startpoints differed by approximately 27 nucleotides. The upstream promoters for ileR and orf83 overlap in their -35 regions.
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PMID:Structural analysis of the ileR locus of Escherichia coli K12. 352 38

The rrnA ribosomal RNA (rRNA) operon of Campylobacter jejuni (Cj) TGH9011 (ATCC43431) was cloned and sequenced to completion. rRNAs were then characterized by primer extension and S1 nuclease mapping analysis. The secondary structure models of Cj 16S and 23S rRNAs were constructed, and the models were compared to the corresponding models from other eubacterial rRNA. The analysis presented a typical 5'-promoter-16S-tRNAs-23S-5S-terminator-3' prokaryotic rRNA operon structure. However, an unusual organization of the intercistronic tRNAs was observed where the two tRNAs, tRNA(Ala) and tRNA(Ile), were present in the order 5'-16S-tRNA(Ala)-tRNA(Ile)-23S-3', which is opposite of the typical 5'-16S-tRNA(Ile)-tRNA(Ala)-23S-3' structure observed in other bacteria.
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PMID:Complete sequences and organization of the rrnA operon from campylobacter jejuni TGH9011 (ATCC43431). 759 Feb 96

Steroid receptor binding factor (RBF) was originally isolated from avian oviduct nuclear matrix. When bound to avian genomic DNA, RBF generates saturable high-affinity binding sites for the avian progesterone receptor (PR). Recent studies have shown that RBF binds to a 54 bp element in the 5'-flanking region of the progesterone-regulated avian c-myc gene, and nuclear matrix-like attachment sites flank the RBF element [Lauber et al. (1997) J. Biol. Chem. 272, 24657-24665]. In this paper, electrophoretic mobility shift assays (EMSAs) and S1 nuclease treatment are used to demonstrate that the RBF-maltose binding protei (MBP) fusion protein binds to single-stranded DNA of its element. Only the N-terminal domain of RBF binds the RBF DNA element as demonstrated by southwestern blot analyses, and by competition EMSAs between RBF-MBP and the N-terminal domain. Mass spectrometric analysis of the C-terminal domain of RBF demonstrates its potential to form noncovalent protein-protein interactions via a potential leucine-isoleucine zipperlike structure, suggesting a homo- and/or possible heterodimer structure in solution. These data support that the nuclear matrix binding site (acceptor site) for PR in the c-myc gene promoter is composed of RBF dimers bound to a specific single-stranded DNA element. The dimers of RBF are generated by C-terminal leucine zipper and the DNA binding occurs at the N-terminal parallel beta-sheet DNA binding motif. This complex is flanked by nuclear matrix attachment sites.
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PMID:Interactions of the nuclear matrix-associated steroid receptor binding factor with its DNA binding element in the c-myc gene promoter. 1065 41