Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.13.3 (histidine kinase)
 2,405 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Porphyromonas gingivalis is a late-colonizing bacterium of the subgingival dental plaque biofilm associated with periodontitis. Two P. gingivalis genes, fimR and fimS, are predicted to encode a two-component signal transduction system comprising a response regulator (FimR) and a sensor histidine kinase (FimS). In this study, we show that fimS and fimR, although contiguous on the genome, are not part of an operon. We inactivated fimR and fimS in both the afimbriated strain W50 and the fimbriated strain ATCC 33277 and demonstrated that both mutants formed significantly less biofilm than their respective wild-type strains. Quantitative reverse transcription-real-time PCR showed that expression of fimbriation genes was reduced in both the fimS and fimR mutants of strain ATCC 33277. The mutations had no effect, in either strain, on the P. gingivalis growth rate or on the response to hydrogen peroxide or growth at pH 9, at 41 degrees C, or at low hemin availability. Transcriptome analysis using DNA microarrays revealed that inactivation of fimS resulted in the differential expression of 10% of the P. gingivalis genome (>1.5-fold; P < 0.05). Notably genes encoding seven different transcriptional regulators, including the fimR gene and three extracytoplasmic sigma factor genes, were differentially expressed in the fimS mutant.
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PMID:FimR and FimS: biofilm formation and gene expression in Porphyromonas gingivalis. 2006 84

Porphyromonas gingivalis, a Gram-negative oral anaerobe, is strongly associated with chronic adult periodontitis, and it utilizes FimA fimbriae to persistently colonize and evade host defenses in the periodontal crevice. The FimA-related gene cluster (the fim gene cluster) is positively regulated by the FimS-FimR two-component system. In this study, comparative analyses between fimbriate type strain ATCC 33277 and fimbria-deficient strain W83 revealed differences in their fimS loci, which encode FimS histidine kinase. Using a reciprocal gene exchange system, we established that FimS from W83 is malfunctional. Complementation analysis with chimeric fimS constructs revealed that W83 FimS has a defective kinase domain due to a truncated conserved G3 box motif that provides an ATP-binding pocket. The introduction of the functional fimS from 33277 restored the production, but not polymerization, of endogenous FimA subunits in W83. Further analyses with a fimA-exchanged W83 isogenic strain showed that even the fimbria-deficient W83 retains the ability to polymerize FimA from 33277, indicating the assembly of mature FimA by a primary structure-dependent mechanism. It also was shown that the substantial expression of 33277-type FimA fimbriae in the W83 derivative requires the introduction and expression of the functional 33277 fimS. These findings indicate that FimSR is the unique and universal regulatory system that activates the fim gene cluster in a fimA genotype-independent manner.
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PMID:Histidine kinase-mediated production and autoassembly of Porphyromonas gingivalis fimbriae. 2011 68