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)

We have applied the technique of Northern blotting hybridization analysis to examine the transcription of the Escherichia coli isoleucyl-tRNA synthetase (ileS) and prolipoprotein signal peptidase (lsp) genes. RNA samples from the wild-type strain CS412 and CS412 containing the plasmids pMT521 and pSYC890 were examined with ileS- and lsp-specific 32P-labeled probes. pMT521 is a pBR322 derivative into which a chromosomal DNA fragment containing the ileS and lsp genes has been cloned downstream of the pBR322 tet promoter. pSYC890 is a derivative of pMT521 which lacks the tet promoter, but nevertheless is active in lsp mRNA transcription due to the presence of a weak lsp internal promoter located in the distal portion of the upstream ileS DNA, RNA from CS412(pMT521) exhibited a high level of a 5500-nucleotide ileS-lsp cotranscript that hybridized to both probes. RNA from CS412(pSYC890) contained a high level of low molecular weight lsp-specific transcripts from the lsp internal promoter. However, only high molecular weight (5000-6500 nucleotides) cotranscripts were detected in RNA from CS412 by Northern blotting analysis. A trace level of lsp-specific mRNA was detected in CS412 by S1 nuclease mapping. The 5'-end of this transcript was mapped using RNA from CS412(pSYC890). The mRNA begins 192/193 base pairs upstream of the lsp translation initiation codon at a site within ileS DNA that codes for the aspartate residue located 61 amino acids from the carboxyl-terminal of ILES. In conclusion, most of the transcription of lsp in wild-type E. coli originates from upstream of ileS and yields ileS-lsp cotranscripts.
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PMID:Cotranscription of the Escherichia coli isoleucyl-tRNA synthetase (ileS) and prolipoprotein signal peptidase (lsp) genes. Fine-structure mapping of the lsp internal promoter. 243 63

In the thermophilic archaeon Methanobacterium thermoautotrophicum Marburg, the structural gene for isoleucyl-tRNA synthetase (ileS) is flanked upstream by orf401 and downstream by purL. orf401 encodes a 43.5-kDa protein with an unknown function. Northern (RNA) hybridization and S1 nuclease protection experiments showed that the orf401, ileS, and purL genes are cotranscribed from an archael consensus promoter in front of orf401. The corresponding transcript was about eightfold increased in cells that had been exposed to pseudomonic acid A, a specific inhibitor of isoleucyl-tRNA synthetase. Growth inhibition by puromycin, tryptophan starvation, or starvation for hydrogen did not affect the level of this transcript. The level of a trpE transcript, however, was drastically elevated upon tryptophan starvation, while inhibition by pseudomonic acid A had no effect on the level of this transcript. Expression of ileS thus appears to be controlled by a regulatory mechanism which specifically responds to the availability of isoleucyl-tRNA. Extensive decay of the orf401-ileS-purL message was observed. Degradation occurred, presumably by endonucleolytic cleavage, within the orf401 region.
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PMID:Transcription of the ileS operon in the archaeon Methanobacterium thermoautotrophicum Marburg. 837 40