A putative TetR regulator is involved in nitric oxide stress resistance in Porphyromonas gingivalis.
To survive in the periodontal pocket, Porphyromonas gingivalis, the main causative agent of periodontal disease, must overcome oxidative and nitric oxide (NO) stress. Previously, we reported that, in the presence of NO comparable to stress conditions, the transcriptome of P. gingivalis was differentially expressed, and genes belonging to the PG1178-81 cluster were significantly upregulated. To further evaluate their role(s) in NO stress resistance, these genes were inactivated by allelic exchange mutagenesis. Isogenic mutants P. gingivalis FLL460 (ΔPG1181::ermF) and FLL461 (ΔPG1178-81::ermF) were black-pigmented, with gingipain and hemolytic activities comparable to that of the wild-type strain. Whereas the recovery of these isogenic mutants from NO stress was comparable to the wild-type, there was increased sensitivity to hydrogen peroxide-induced stress. RNA-Seq analysis under conditions of NO stress showed that approximately 5 and 8% of the genome was modulated in P. gingivalis FLL460 and FLL461, respectively. The PG1178-81 gene cluster was shown to be part of the same transcriptional unit and is inducible in response to NO stress. In the presence of NO, PG1181, a putative transcriptional regulator, was shown to bind to its own promoter region and that of several other NO responsive genes including PG0214 an extracytoplasmic function σ factor, PG0893 and PG1236. Taken together, the data suggest that PG1181 is a NO responsive transcriptional regulator that may play an important role in the NO stress resistance regulatory network in P. gingivalis.
Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
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Boutrin
School of Pharmacy, Fudan University, Shanghai, China.
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Y
Yu
Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
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Wang
Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
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Aruni
Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.
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Y
Dou
School of Pharmacy, Fudan University, Shanghai, China.
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Shi
Division of Microbiology and Molecular Genetics, Department of Basic Sciences, School of Medicine, Loma Linda University, Loma Linda, CA, USA.|Institute of Oral Biology, Kyung Hee University, Seoul, Korea.
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Fletcher
D018829:Adhesins, Bacterial / Q000378:metabolism; D000483:Alleles; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D006861:Hydrogen Peroxide / Q000494:pharmacology; D005810:Multigene Family; D016296:Mutagenesis; D009154:Mutation; D009569:Nitric Oxide / Q000494:pharmacology*; D018384:Oxidative Stress; D016966:Porphyromonas gingivalis / Q000187:drug effects* / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D050436:Regulatory Elements, Transcriptional; D017423:Sequence Analysis, RNA; D012808:Sigma Factor; D013312:Stress, Physiological
D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D000080867:Gingipain Cysteine Endopeptidases; D012808:Sigma Factor; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D003546:Cysteine Endopeptidases
nitric oxide; stress resistance; transcription regulation