Role of an extracytoplasmic function sigma factor, PGN_0319, in hemin utilization by Porphyromonas gingivalis

ABSTRACT: Extracytoplasmic function (ECF) sigma factors are known to play an important role in the bacterial response to various environmental stresses. Porphyromonas gingivalis, a prominent etiological agent in human periodontitis, possesses six putative ECF sigma factors. So far, information is limited on an ECF sigma factor, PGN_0319. It has been recently reported that the expression of genes encoding some of the ECF sigma factors including PGN_0319 was affected by hemin availability. The aim of this study was to evaluate the role of PGN_0319 in hemin utilization by P. gingivalis. We evaluated the gene expression profile of the PGN_0319 mutant by DNA microarray, and then real-time reverse transcription PCR analysis was performed to assess genes with altered expression levels. The expressions level of hmuY and hmuR, which encode an outer-membrane protein involved in hemin utilization, and cdhR, a transcriptional regulator of hmuYR, were significantly decreased in the PGN_0319 mutant. The transcription of these genes was restored in the PGN_0319 complemented strain. We observed that the PGN_0319 mutant showed reduced growth in log phase compared with wild type under hemin-limiting condition. By electrophoretic mobility shift assay we demonstrated the recombinant PGN_0319 protein bound to the promoter region of hmuY and cdhR. In addition, we observed that PGN_0319 gene was upregulated in response to low cell density. These results demonstrate that PGN_0319 play an important role in the early growth of P. gingivalis, and directly regulates hmuYR and cdhR, thereby plays a role in the mechanisms involved in hemin utilization by P. gingivalis.

ORGANISM(S): Porphyromonas gingivalis ATCC 33277 Porphyromonas gingivalis

PROVIDER: GSE78048 | GEO | 2017/01/01

SECONDARY ACCESSION(S): PRJNA312444

REPOSITORIES: GEO