Abstract:
:In bacteria, DNA supercoil movement is restricted to subchromosomal regions or 'domains.' To elucidate the nature of domain boundaries, we analysed reaction kinetics for gammadelta site-specific resolution in six chromosomal intervals ranging in size from 14 to 90 kb. In stationary cultures of Salmonella typhimurium, resolution kinetics were rapid for both short and long intervals, suggesting that random stationary barriers occur with a 30% probability at approximately 80 kb intervals along DNA. To test the biochemical nature of domain barriers, a genetic screen was used to look for mutants with small domains. Rare temperature-sensitive alleles of DNA gyrase and Topo IV (the two essential type II topoisomerases) had more supercoil barriers than wild-type strains in all growth states. The most severe gyrase mutants were found to have twice as many barriers in growing cells as wild type throughout a 90 kb interval of the chromosome. We propose that knots and tangles in duplex DNA restrain supercoil diffusion in living bacteria.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Staczek P,Higgins NPdoi
10.1046/j.1365-2958.1998.01025.xsubject
Has Abstractpub_date
1998-09-01 00:00:00pages
1435-48issue
6eissn
0950-382Xissn
1365-2958journal_volume
29pub_type
杂志文章abstract::ecs is a three-cistron operon of Bacillus subtilis, encoding proteins with similarity to the ATPase (EcsA) and hydrophobic components (EcsB) of ABC transporters. The ecsA26 point mutation was shown to cause a strong processing defect of a secreted alpha-amylase precursor (preAmyQ) and of three other exoproteins. North...
journal_title:Molecular microbiology
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journal_title:Molecular microbiology
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pub_type: 杂志文章,评审
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pub_type: 杂志文章
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更新日期:1991-09-01 00:00:00
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pub_type: 杂志文章
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pub_type: 评论,杂志文章
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journal_title:Molecular microbiology
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更新日期:2013-06-01 00:00:00
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更新日期:1999-09-01 00:00:00
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更新日期:2014-06-01 00:00:00