Abstract:
:The recently identified recA gene of the naturally transformable bacterium Streptococcus pneumoniae has been further characterized by constructing a recA null mutation and by investigating its regulation. The recA mutation has been shown to confer both DNA repair (as judged from sensitivity to u.v. and methyl methane sulphonate) and recombination deficiencies. Plasmid transformation into the recA mutant was also drastically reduced. Western blotting established that recA gene expression is increased several fold at the onset of competence for genetic transformation. Increased expression was associated with the appearance of a recA-specific transcript, approximately 5.7 kb long. This transcript indicated that recA is part of a competence-inducible (cin) operon. The major (about 4.3 kb) transcript detected from non-competent cells did not include cinA, the first gene in the operon, suggesting that this gene could be specifically required at some stage in the transformation process. Detection of small amounts of the 5.7 kb polycistronic mRNA in cells treated with mitomycin C suggested that the operon could also be damage inducible. In addition, mitomycin C treatment of a recA- lysogenic strain did not lead to prophage induction and cell lysis. This is unlike the situation of a recA+ lysogen. Together these results demonstrate that RecA controls lysogenic induction and suggest the existence of a SOS repair system in S. pneumoniae.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Martin B,García P,Castanié MP,Claverys JPdoi
10.1111/j.1365-2958.1995.tb02250.xsubject
Has Abstractpub_date
1995-01-01 00:00:00pages
367-79issue
2eissn
0950-382Xissn
1365-2958journal_volume
15pub_type
杂志文章abstract::Like other bacterial species, Mycobacterium tuberculosis has multiple sigma (sigma) factors encoded in its genome. In previously published work, we and others have shown that mutations in some of these transcriptional activators render M. tuberculosis sensitive to various environmental stresses and, in some cases, cau...
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pub_type: 杂志文章
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pub_type: 杂志文章
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更新日期:1989-11-01 00:00:00
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更新日期:2004-06-01 00:00:00
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更新日期:2017-02-01 00:00:00
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pub_type: 杂志文章
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更新日期:2003-03-01 00:00:00
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