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Elevated levels of VCA0117 (VasH) in response to external signals activate the type VI secretion system of Vibrio cholerae O1 El Tor A1552

Seibt, Henrik ; Aung, Kyaw Min ; Ishikawa, Takahiko ; Sjöström, Annika ; Gullberg, Martin ; Atkinson, Gemma Catherine LU ; Wai, Sun Nyunt and Shingler, Victoria (2020) In Environmental Microbiology 22(10). p.4409-4423
Abstract

The type VI nanomachine is critical for Vibrio cholerae to establish infections and to thrive in niches co-occupied by competing bacteria. The genes for the type VI structural proteins are encoded in one large and two small auxiliary gene clusters. VCA0117 (VasH) - a σ54 -transcriptional activator - is strictly required for functionality of the type VI secretion system since it controls production of the structural protein Hcp. While some strains constitutively produce a functional system, others do not and require specific growth conditions of low temperature and high osmolarity for expression of the type VI machinery. Here, we trace integration of these regulatory signals to the promoter activity of the large gene cluster in which... (More)

The type VI nanomachine is critical for Vibrio cholerae to establish infections and to thrive in niches co-occupied by competing bacteria. The genes for the type VI structural proteins are encoded in one large and two small auxiliary gene clusters. VCA0117 (VasH) - a σ54 -transcriptional activator - is strictly required for functionality of the type VI secretion system since it controls production of the structural protein Hcp. While some strains constitutively produce a functional system, others do not and require specific growth conditions of low temperature and high osmolarity for expression of the type VI machinery. Here, we trace integration of these regulatory signals to the promoter activity of the large gene cluster in which many components of the machinery and VCA0117 itself are encoded. Using in vivo and in vitro assays and variants of VCA0117, we show that activation of the σ54 -promoters of the auxiliary gene clusters by elevated VCA0117 levels are all that is required to overcome the need for specialized growth conditions. We propose a model in which signal integration via the large operon promoter directs otherwise restrictive levels of VCA0117 that ultimately dictates a sufficient supply of Hcp for completion of a functional type VI secretion system.

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author
; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
Bacterial Proteins/metabolism, Gene Expression Regulation, Bacterial/genetics, Multigene Family/genetics, Promoter Regions, Genetic/genetics, Signal Transduction/physiology, Transcriptional Activation/genetics, Type VI Secretion Systems/metabolism, Vibrio cholerae O1/genetics
in
Environmental Microbiology
volume
22
issue
10
pages
4409 - 4423
publisher
Wiley-Blackwell
external identifiers
  • scopus:85087672984
  • pmid:32592280
ISSN
1462-2920
DOI
10.1111/1462-2920.15141
language
English
LU publication?
no
id
aea0016b-98fc-4d88-ba43-6dbce6e9e9e9
date added to LUP
2021-09-27 15:51:38
date last changed
2024-06-29 18:01:45
@article{aea0016b-98fc-4d88-ba43-6dbce6e9e9e9,
  abstract     = {{<p>The type VI nanomachine is critical for Vibrio cholerae to establish infections and to thrive in niches co-occupied by competing bacteria. The genes for the type VI structural proteins are encoded in one large and two small auxiliary gene clusters. VCA0117 (VasH) - a σ54 -transcriptional activator - is strictly required for functionality of the type VI secretion system since it controls production of the structural protein Hcp. While some strains constitutively produce a functional system, others do not and require specific growth conditions of low temperature and high osmolarity for expression of the type VI machinery. Here, we trace integration of these regulatory signals to the promoter activity of the large gene cluster in which many components of the machinery and VCA0117 itself are encoded. Using in vivo and in vitro assays and variants of VCA0117, we show that activation of the σ54 -promoters of the auxiliary gene clusters by elevated VCA0117 levels are all that is required to overcome the need for specialized growth conditions. We propose a model in which signal integration via the large operon promoter directs otherwise restrictive levels of VCA0117 that ultimately dictates a sufficient supply of Hcp for completion of a functional type VI secretion system.</p>}},
  author       = {{Seibt, Henrik and Aung, Kyaw Min and Ishikawa, Takahiko and Sjöström, Annika and Gullberg, Martin and Atkinson, Gemma Catherine and Wai, Sun Nyunt and Shingler, Victoria}},
  issn         = {{1462-2920}},
  keywords     = {{Bacterial Proteins/metabolism; Gene Expression Regulation, Bacterial/genetics; Multigene Family/genetics; Promoter Regions, Genetic/genetics; Signal Transduction/physiology; Transcriptional Activation/genetics; Type VI Secretion Systems/metabolism; Vibrio cholerae O1/genetics}},
  language     = {{eng}},
  number       = {{10}},
  pages        = {{4409--4423}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Environmental Microbiology}},
  title        = {{Elevated levels of VCA0117 (VasH) in response to external signals activate the type VI secretion system of Vibrio cholerae O1 El Tor A1552}},
  url          = {{http://dx.doi.org/10.1111/1462-2920.15141}},
  doi          = {{10.1111/1462-2920.15141}},
  volume       = {{22}},
  year         = {{2020}},
}