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A putative TetR regulator is involved in nitric oxide stress resistance in P orphyromonas gingivalis
Author(s) -
Boutrin M.C.,
Yu Y.,
Wang C.,
Aruni W.,
Dou Y.,
Shi L.,
Fletcher H.M.
Publication year - 2016
Publication title -
molecular oral microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 77
eISSN - 2041-1014
pISSN - 2041-1006
DOI - 10.1111/omi.12128
Subject(s) - porphyromonas gingivalis , mutant , regulator , gene , mutagenesis , nitric oxide , microbiology and biotechnology , transcriptional regulation , gene cluster , transcriptome , biology , chemistry , gene expression , genetics , bacteria , endocrinology
Summary 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 PG 1178‐81 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 FLL 460 (Δ PG 1181 :: ermF) and FLL 461 (Δ PG 1178‐81 :: 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 FLL 460 and FLL 461, respectively. The PG 1178‐81 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 , PG 1181, a putative transcriptional regulator, was shown to bind to its own promoter region and that of several other NO responsive genes including PG 0214 an extracytoplasmic function σ factor, PG 0893 and PG 1236 . Taken together, the data suggest that PG 1181 is a NO responsive transcriptional regulator that may play an important role in the NO stress resistance regulatory network in P. gingivalis .