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 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.
journal_name
Environ Microbioljournal_title
Environmental microbiologyauthors
Seibt H,Aung KM,Ishikawa T,Sjöström A,Gullberg M,Atkinson GC,Wai SN,Shingler Vdoi
10.1111/1462-2920.15141subject
Has Abstractpub_date
2020-10-01 00:00:00pages
4409-4423issue
10eissn
1462-2912issn
1462-2920journal_volume
22pub_type
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