PMID:20511505

Citation	Johnson, JG and Clegg, S (2010) Role of MrkJ, a phosphodiesterase, in type 3 fimbrial expression and biofilm formation in Klebsiella pneumoniae. J. Bacteriol. 192:3944-50
Abstract	Klebsiella pneumoniae is an opportunistic pathogen that has been shown to adhere to human extracellular matrices using the type 3 fimbriae. Introduction of plasmids carrying genes known to alter intracellular cyclic-di-GMP pools in Vibrio parahaemolyticus revealed that these genes also altered type 3 fimbrial surface expression in K. pneumoniae. Immediately adjacent to the type 3 fimbrial gene cluster is a gene, mrkJ, that is related to a family of bacterial genes encoding phosphodiesterases. We identify here a role for MrkJ, a functional phosphodiesterase exhibiting homology to EAL domain-containing proteins, in controlling type 3 fimbria production and biofilm formation in K. pneumoniae. Deletion of mrkJ resulted in an increase in type 3 fimbria production and biofilm formation as a result of the accumulation of intracellular cyclic-di-GMP. This gene was shown to encode a functional phosphodiesterase via restoration of motility in a V. parahaemolyticus strain previously shown to accumulate cyclic-di-GMP and in vitro using phosphodiesterase activity assays. The effect of the mrkJ mutation on type 3 fimbrial expression was shown to be at the level of mrkA gene transcription by using quantitative reverse transcription-PCR. These results reveal a previously unknown role for cyclic-di-GMP in type 3 fimbrial production.
Links	PubMed PMC2916373 Online version:10.1128/JB.00304-10
Keywords	Biofilms/growth & development; Escherichia coli Proteins; Fimbriae Proteins/genetics; Fimbriae Proteins/metabolism; Gene Expression Regulation, Bacterial/physiology; Gene Expression Regulation, Enzymologic/physiology; Klebsiella pneumoniae/enzymology; Klebsiella pneumoniae/genetics; Klebsiella pneumoniae/physiology; Multigene Family; Mutation; Phosphoric Diester Hydrolases/genetics; Phosphoric Diester Hydrolases/metabolism; Phosphorus-Oxygen Lyases/metabolism; Plasmids; Transcription, Genetic
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
KLEPN:G0GUB8		GO:0071111: cyclic-guanylate-specific phosphodiesterase activity	IDA: Inferred from Direct Assay:	F	Fig 2B shows the phosphodiesterase activity of MrkJ.	complete CACAO 4983

References

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