Identification and characterization of a phosphodiesterase that inversely regulates motility and biofilm formation in Vibrio cholerae.
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 all V. 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 and in vitro enzymatic activity assays revealed that CdgJ functions as a PDE. The cdgJ mutant had reduced motility and exhibited a small decrease in flaA expression; however, it was able to produce a flagellum. This mutant had enhanced biofilm formation and vps 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 in V. cholerae.
Liu
Xianxian
X
Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064, USA.
Beyhan
Sinem
S
Lim
Bentley
B
Linington
Roger G
RG
Yildiz
Fitnat H
FH
D018441:Biofilms / Q000254:growth & development*; D002853:Chromatography, Liquid; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014734:Vibrio cholerae / Q000201:enzymology* / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure
C062025:bis(3',5')-cyclic diguanylic acid; D010727:Phosphoric Diester Hydrolases; D006152:Cyclic GMP