Open AccessIdentification and Characterization of a Phosphodiesterase That Inversely Regulates Motility and Biofilm Formation in Vibrio cholerae
Author(s) -
Xianxian Liu,
Sinem Beyhan,
Bentley Lim,
Roger G. Linington,
Fitnat H. Yildiz
Publication year - 2010
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.00209-10
Subject(s) - vibrio cholerae , mutant , biology , motility , biofilm , phosphodiesterase , microbiology and biotechnology , flagellum , mutation , gene , biochemistry , genetics , enzyme , bacteria
Vibrio cholerae switches between free-living motile and surface-attached sessile lifestyles. Cyclic diguanylate (c-di-GMP) is a signaling molecule controlling such lifestyle changes. C-di-GMP is synthesized by diguanylate cyclases (DGCs) that contain a GGDEF domain and is degraded by phosphodiesterases (PDEs) that contain an EAL or HD-GYP domain. We constructed in-frame deletions of allV. cholerae genes encoding proteins with GGDEF and/or EAL domains and screened mutants for altered motility phenotypes. Of 52 mutants tested, four mutants exhibited an increase in motility, while three mutants exhibited a decrease in motility. We further characterized one mutant lacking VC0137 (cdgJ ), which encodes an EAL domain protein. Cellular c-di-GMP quantifications andin vitro enzymatic activity assays revealed that CdgJ functions as a PDE. ThecdgJ mutant had reduced motility and exhibited a small decrease inflaA expression; however, it was able to produce a flagellum. This mutant had enhanced biofilm formation andvps gene expression compared to that of the wild type, indicating that CdgJ inversely regulates motility and biofilm formation. Genetic interaction analysis revealed that at least four DGCs, together with CdgJ, control motility inV. cholerae .