Abstract:
:H-NS is an abundant nucleoid-associated protein involved in the maintenance of chromosomal architecture in bacteria. H-NS also has a role in silencing the expression of a variety of environmentally regulated genes during growth under nonpermissive conditions. In this study we demonstrate a role for H-NS in the negative modulation of expression of several genes within the ToxR virulence regulon of Vibrio cholerae. Deletion of hns resulted in high, nearly constitutive levels of expression of the genes encoding cholera toxin, toxin-coregulated pilus, and the ToxT virulence gene regulatory protein. For the cholera toxin- and ToxT-encoding genes, elevated expression in an hns mutant was found to occur in the absence of the cognate activator proteins, suggesting that H-NS functions directly at these promoters to decrease gene expression. Deletion analysis of the region upstream of toxT suggests that an extensive region located far upstream of the transcriptional start site is required for complete H-NS-mediated repression of gene expression. These data indicate that H-NS negatively influences multiple levels of gene expression within the V. cholerae virulence cascade and raise the possibility that the transcriptional activator proteins in the ToxR regulon function to counteract the repressive effects of H-NS at the various promoters as well as to recruit RNA polymerase.
journal_name
J Bacterioljournal_title
Journal of bacteriologyauthors
Nye MB,Pfau JD,Skorupski K,Taylor RKdoi
10.1128/jb.182.15.4295-4303.2000keywords:
subject
Has Abstractpub_date
2000-08-01 00:00:00pages
4295-303issue
15eissn
0021-9193issn
1098-5530journal_volume
182pub_type
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更新日期:1976-11-01 00:00:00
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更新日期:1993-08-01 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:1969-02-01 00:00:00
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pub_type: 杂志文章
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更新日期:1998-09-01 00:00:00
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pub_type: 杂志文章
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journal_title:Journal of bacteriology
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doi:10.1128/JB.135.3.1149-1150.1978
更新日期:1978-09-01 00:00:00
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pub_type: 杂志文章
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更新日期:1964-07-01 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.17.5175-5181.2003
更新日期:2003-09-01 00:00:00
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更新日期:2019-02-25 00:00:00
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journal_title:Journal of bacteriology
pub_type: 杂志文章
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更新日期:1995-08-01 00:00:00
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pub_type: 杂志文章
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更新日期:2001-03-01 00:00:00
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pub_type: 杂志文章
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更新日期:2000-02-01 00:00:00
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更新日期:1966-03-01 00:00:00