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Vibrio cholerae CsrA Regulates ToxR Levels in Response to Amino Acids and Is Essential for Virulence.

Mey AR, Butz HA, Payne SM - MBio (2015)

Bottom Line: Conversely, specific amino acid substitutions in CsrA were associated with defects in ToxR production in response to NRES.Unlike previously described effects of CsrA on virulence gene regulation, the effects of CsrA on ToxR were not mediated through quorum sensing and HapR.By linking environmental sensing to the ToxR regulon, CsrA effectively acts as a switch that controls pathogenesis in response to specific signals.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA armey@austin.utexas.edu.

No MeSH data available.


Related in: MedlinePlus

Mutation of varA causes growth defects and results in an abnormal pattern of OMP and ToxR expression. (A) N16961 (WT), the ΔvarA::cam mutant (NvarAS), the vector control strain NvarAS/pWKS30, and the complemented strain NvarAS/pVarA were grown overnight in LB broth and then subcultured 1:100 into fresh LB or T medium and grown for 6 h. (B) N16961 and NvarAS were grown overnight in LB broth and then subcultured 1:100 into T medium with or without 12.5 mM NRES mix. Cells were harvested in mid-log phase, and whole-cell preparations were resolved by SDS-PAGE (10%) and stained by Coomassie blue (top panel) or immunoblotted using polyclonal anti-ToxR antisera (bottom panel).
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fig2: Mutation of varA causes growth defects and results in an abnormal pattern of OMP and ToxR expression. (A) N16961 (WT), the ΔvarA::cam mutant (NvarAS), the vector control strain NvarAS/pWKS30, and the complemented strain NvarAS/pVarA were grown overnight in LB broth and then subcultured 1:100 into fresh LB or T medium and grown for 6 h. (B) N16961 and NvarAS were grown overnight in LB broth and then subcultured 1:100 into T medium with or without 12.5 mM NRES mix. Cells were harvested in mid-log phase, and whole-cell preparations were resolved by SDS-PAGE (10%) and stained by Coomassie blue (top panel) or immunoblotted using polyclonal anti-ToxR antisera (bottom panel).

Mentions: The N16961 varA mutant (NvarA) produced a mixture of large and small colonies. The small-colony variant, NvarAS, exhibited reduced growth in liquid culture compared with the wild-type parental strain, especially in a minimal medium (Fig. 2A). Growth was restored to wild-type levels when pVarA, a low-copy-number plasmid containing the cloned varA gene, was introduced into the NvarAS strain (Fig. 2A), showing that the poor growth of NvarAS was due solely to the lack of a functional VarA.


Vibrio cholerae CsrA Regulates ToxR Levels in Response to Amino Acids and Is Essential for Virulence.

Mey AR, Butz HA, Payne SM - MBio (2015)

Mutation of varA causes growth defects and results in an abnormal pattern of OMP and ToxR expression. (A) N16961 (WT), the ΔvarA::cam mutant (NvarAS), the vector control strain NvarAS/pWKS30, and the complemented strain NvarAS/pVarA were grown overnight in LB broth and then subcultured 1:100 into fresh LB or T medium and grown for 6 h. (B) N16961 and NvarAS were grown overnight in LB broth and then subcultured 1:100 into T medium with or without 12.5 mM NRES mix. Cells were harvested in mid-log phase, and whole-cell preparations were resolved by SDS-PAGE (10%) and stained by Coomassie blue (top panel) or immunoblotted using polyclonal anti-ToxR antisera (bottom panel).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526715&req=5

fig2: Mutation of varA causes growth defects and results in an abnormal pattern of OMP and ToxR expression. (A) N16961 (WT), the ΔvarA::cam mutant (NvarAS), the vector control strain NvarAS/pWKS30, and the complemented strain NvarAS/pVarA were grown overnight in LB broth and then subcultured 1:100 into fresh LB or T medium and grown for 6 h. (B) N16961 and NvarAS were grown overnight in LB broth and then subcultured 1:100 into T medium with or without 12.5 mM NRES mix. Cells were harvested in mid-log phase, and whole-cell preparations were resolved by SDS-PAGE (10%) and stained by Coomassie blue (top panel) or immunoblotted using polyclonal anti-ToxR antisera (bottom panel).
Mentions: The N16961 varA mutant (NvarA) produced a mixture of large and small colonies. The small-colony variant, NvarAS, exhibited reduced growth in liquid culture compared with the wild-type parental strain, especially in a minimal medium (Fig. 2A). Growth was restored to wild-type levels when pVarA, a low-copy-number plasmid containing the cloned varA gene, was introduced into the NvarAS strain (Fig. 2A), showing that the poor growth of NvarAS was due solely to the lack of a functional VarA.

Bottom Line: Conversely, specific amino acid substitutions in CsrA were associated with defects in ToxR production in response to NRES.Unlike previously described effects of CsrA on virulence gene regulation, the effects of CsrA on ToxR were not mediated through quorum sensing and HapR.By linking environmental sensing to the ToxR regulon, CsrA effectively acts as a switch that controls pathogenesis in response to specific signals.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas, USA armey@austin.utexas.edu.

No MeSH data available.


Related in: MedlinePlus