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Cyclic di‐ GMP inhibits V ibrio cholerae motility by repressing induction of transcription and inducing extracellular polysaccharide production
Author(s) -
Srivastava Disha,
Hsieh MengLun,
Khataokar Atul,
Neiditch Matthew B.,
Waters Christopher M.
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12432
Subject(s) - regulon , vibrio cholerae , biology , motility , operon , mutant , microbiology and biotechnology , extracellular , transcription (linguistics) , two component regulatory system , regulator , biochemistry , response regulator , gene , bacteria , genetics , linguistics , philosophy
Summary Cyclic di‐ GMP (c‐di‐ GMP ) controls the transition between sessility and motility in many bacterial species. This regulation is achieved by a variety of mechanisms including alteration of transcription initiation and inhibition of flagellar function. How c‐di‐ GMP inhibits the motility of V ibrio cholerae has not been determined . FlrA , a homologue of the c‐di‐ GMP binding P seudomonas aeruginosa motility regulator FleQ , is the master regulator of the V . cholerae flagellar biosynthesis regulon. Here we show that binding of c‐di‐ GMP to FlrA abrogates binding of FlrA to the promoter of the flrBC operon, deactivating expression of the flagellar biosynthesis regulon. FlrA does not regulate expression of extracellular V ibrio polysaccharide ( VPS ) synthesis genes. Mutation of the FlrA amino acids R 135 and R 176 to histidine abrogates binding of c‐di‐ GMP to FlrA , rendering FlrA active in the presence of high levels of c‐di‐ GMP . Surprisingly, c‐di‐ GMP still inhibited the motility of V . cholerae only expressing the c‐di‐ GMP blind FlrA ( R 176 H ) mutant. We determined that this flagellar transcription‐independent inhibition is due to activation of VPS production by c‐di‐ GMP . Therefore, c‐di‐ GMP prevents motility of V . cholerae by two distinct but functionally redundant mechanisms.