RsmA and AmrZ orchestrate the assembly of all three type VI secretion systems in Pseudomonas aeruginosa
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Supporting information
Accepted version
Author(s)
Type
Journal Article
Abstract
The type VI secretion system (T6SS) is a weapon of bacterial warfare and host cell subversion. The Gram-negative pathogen Pseudomonas aeruginosa has three T6SSs involved in colonization, competition, and full virulence. H1-T6SS is a molecular gun firing seven toxins, Tse1–Tse7, challenging survival of other bacteria and helping P. aeruginosa to prevail in specific niches. The H1-T6SS characterization was facilitated through studying a P. aeruginosa strain lacking the RetS sensor, which has a fully active H1-T6SS, in contrast to the parent. However, study of H2-T6SS and H3-T6SS has been neglected because of a poor understanding of the associated regulatory network. Here we performed a screen to identify H2-T6SS and H3-T6SS regulatory elements and found that the posttranscriptional regulator RsmA imposes a concerted repression on all three T6SS clusters. A higher level of complexity could be observed as we identified a transcriptional regulator, AmrZ, which acts as a negative regulator of H2-T6SS. Overall, although the level of T6SS transcripts is fine-tuned by AmrZ, all T6SS mRNAs are silenced by RsmA. We expanded this concept of global control by RsmA to VgrG spike and T6SS toxin transcripts whose genes are scattered on the chromosome. These observations triggered the characterization of a suite of H2-T6SS toxins and their implication in direct bacterial competition. Our study thus unveils a central mechanism that modulates the deployment of all T6SS weapons that may be simultaneously produced within a single cell.
Date Issued
2017-07-18
Date Acceptance
2017-06-06
Citation
Proceedings of the National Academy of Sciences of the United States of America, 2017, 114 (29), pp.7707-7712
ISSN
1091-6490
Publisher
National Academy of Sciences
Start Page
7707
End Page
7712
Journal / Book Title
Proceedings of the National Academy of Sciences of the United States of America
Volume
114
Issue
29
Copyright Statement
© 2017 National Academy of Sciences.
Sponsor
Commission of the European Communities
Commission of the European Communities
Biotechnology and Biological Sciences Research Council (BBSRC)
Medical Research Council (MRC)
Medical Research Council (MRC)
Biotechnology and Biological Sciences Research Council (BBSRC)
Identifier
https://www.pnas.org/content/114/29/7707/
Grant Number
328261
625318
BB/N02539/1
MR/K001930/1
MR/N023250/1
BB/L007959/1
Subjects
Science & Technology
Multidisciplinary Sciences
Science & Technology - Other Topics
T6SS
Pseudomonas
RsmA
AmrZ
BIOFILM FORMATION
EXPRESSION
EFFECTORS
PROTEINS
TARGETS
LOCUS
RNA
PATHOGENESIS
TEMPERATURE
STRAIN
AmrZ
Pseudomonas
RsmA
T6SS
Bacterial Proteins
Bacterial Toxins
Cluster Analysis
Gene Deletion
Gene Regulatory Networks
Immune System
Lac Operon
Mutagenesis
Plasmids
Pseudomonas aeruginosa
RNA, Bacterial
Transcription, Genetic
Type VI Secretion Systems
Virulence
Immune System
Pseudomonas aeruginosa
Bacterial Proteins
RNA, Bacterial
Bacterial Toxins
Cluster Analysis
Virulence
Transcription, Genetic
Mutagenesis
Gene Deletion
Lac Operon
Plasmids
Gene Regulatory Networks
Type VI Secretion Systems
Publication Status
Published
Date Publish Online
2017-07-03