Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Analysis of ToxT regulon in Vibrio cholerae El Tor

ABSTRACT: Using a combination of ChIP-seq and RNA-seq we show that ToxT regulates expression of the small RNA TarB. TarB modulates the expression level of the transcriptioanl repressor VC0177. VC0177 controls expression of several genes including VC0179. The function of the Vibrio 7th pandemic island-1 (VSP-1) in cholera pathogenesis has remained obscure. Utilizing ChIP-seq and RNA-seq to map the regulon of the master virulence regulator ToxT, we identify a TCP island encoded small RNA that reduces the expression of a previously unrecognized VSP-1 encoded transcription factor termed VspR. VspR modulates the expression of several VSP-1 genes including one that encodes a novel class of di-nucleotide cyclase (DncV), which preferentially synthesizes a previously undescribed hybrid cyclic AMP-GMP molecule. We show that DncV is required for efficient intestinal colonization and down-regulates V. cholerae chemotaxis, a phenotype previously associated with hyperinfectivity. This pathway couples the actions of previously disparate genomic islands, defines VSP-1 as a pathogenicity island in V. cholerae and implicates its occurrence in 7th pandemic strains as a benefit for host adaptation through the production of a regulatory cyclic di-nucleotide.

ORGANISM(S): Vibrio cholerae O1 str. C6706

SUBMITTER: Bryan Davies

PROVIDER: E-GEOD-36373 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Coordinated regulation of accessory genetic elements produces cyclic di-nucleotides for V. cholerae virulence.

Davies Bryan W BW Bogard Ryan W RW Young Travis S TS Mekalanos John J JJ

Cell 20120401 2

The function of the Vibrio 7(th) pandemic island-1 (VSP-1) in cholera pathogenesis has remained obscure. Utilizing chromatin immunoprecipitation sequencing and RNA sequencing to map the regulon of the master virulence regulator ToxT, we identify a TCP island-encoded small RNA that reduces the expression of a previously unrecognized VSP-1-encoded transcription factor termed VspR. VspR modulates the expression of several VSP-1 genes including one that encodes a novel class of di-nucleotide cyclase ...[more]

PMID: 22500802

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Project description:The cholera disease bacterium V. cholerae, can adopt planktonic or biofilm lifestyles depending on the intracellular concentration of the second messenger cyclic diguanylic acid (c-di-GMP). Biofilm formation protects Vibrios from stressful conditions and facilitates disease transmission by enhancing infectivity. The histone-like nucleoid structuring protein (H-NS) is a global regulator of genes associated with pathogenicity and responses to environmental stresses. H-NS represses the transcription of genes vpsT, vpsA and vpsL, which are required for the biosynthesis of the biofilm exopolysacchide matrix. Here we demonstrate that the c-di-GMP-binding protein VpsT disrupts H-NS nucleoprotein complexes at the vpsA and vpsL promoters and that this effect is enhanced by c-di-GMP. We used ChIP coupled with Next Generation Sequencing (ChIP-Seq) and transcriptome analysis (RNA-Seq) to identify additional loci repressed by H-NS affecting biofilm formation. This study showed that H-NS directly represses the transcription of genes encoding proteins present in the biofilm matrix such as the rbmA-F cluster, hemolysin and chitinase. Similar to vpsA and vpsL, the promoter region of vpsU, rbmA and rbmF exhibited overlapping H-NS and VpsT binding motifs. Deletion of vpsT increased H-NS occupancy at the vpsU, vpsA, vpsL, rbmA and rbmF promoters. Conversely, artificially increasing the c-di-GMP pool diminished H-NS occupancy at the above promoters. Deletion of vpsT did not affect H-NS occupancy at its own promoter. However, deletion of genes encoding the regulators AphA and VpsR significantly increased H-NS occupancy at the vpsT promoter. In sum, our study shows that c-di-GMP enhances biofilm formation by acting through VpsT to activate an H-NS anti-repression cascade. The Binding profile of V. cholerae H-NS to the genome was determined by ChIP followed by Next Generation Sequencing (ChIP-Seq) using the Illumina HiSeq2000 platform. V. cholerae C7258 cells expressing H-NS-FLAG fusion protein from the hns transcription and translation signals were collected from LB cultures grown to mid-exponential phase (OD600 0.5). An anti-FLAG Immunoprecipitation (IP) and an Input samples were used for the analysis.

Dataset Information

Analysis of ToxT regulon in Vibrio cholerae El Tor

Publications

Coordinated regulation of accessory genetic elements produces cyclic di-nucleotides for V. cholerae virulence.

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