HcpR of Porphyromonas gingivalis Is Required for Growth under Nitrosative Stress and Survival within Host Cells
HcpR of Porphyromonas gingivalis Is Required for Growth under Nitrosative Stress and Survival within Host Cells
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DOI：
10.1128/iai.00561-12
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发表时间：
2012-09-01
影响因子：
3.1
通讯作者：
Anaya-Bergman, Cecilia
中科院分区：
文献类型：
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作者：
Lewis, Janina P.;Yanamandra, Sai S.;Anaya-Bergman, Cecilia
虽然革兰氏阴性厌氧牙周病原体牙龈卟啉单胞菌必须承受亚硝化应力，这是特别高的口腔，机制允许保护这种压力是未知的，在这种生物体。在这项研究中，牙龈卟啉单胞菌对亚硝酸盐和一氧化氮的转录反应的微阵列分析显示，编码杂合簇蛋白（HCP）的PG 0893基因的急剧上调，HCP是一种推定的羟胺还原酶。虽然在大肠杆菌中hcp的调控是依赖于OxyR的，但在牙龈卟啉单胞菌中，其表达依赖于Fnr样调控因子HcpR。与野生型W83菌株相比，在亚硝酸盐（P < 0.002）和产生一氧化氮的亚硝基谷胱甘肽（GSNO）（P < 0.001）存在下，在hcpR（PG 1053）基因内含有ermF-ermAM插入的同基因突变体V2807的生长显著降低。此外，PG 0893（hcp）的上调被废除在V2807暴露于亚硝化胁迫。此外，重组HcpR结合DNA含有hcp启动子序列，和结合是氯化血红素依赖性。最后，V2807不能与宿主细胞一起存活，表明HcpR在牙龈卟啉单胞菌毒力中起重要作用。这项工作提供了深入了解的分子机制，保护对亚硝化应激牙龈卟啉单胞菌，并表明，监管机制不同于那些在E。杆菌
Although the Gram-negative, anaerobic periodontopathogen Porphyromonas gingivalis must withstand nitrosative stress, which is particularly high in the oral cavity, the mechanisms allowing for protection against such stress are not known in this organism. In this study, microarray analysis of P. gingivalis transcriptional response to nitrite and nitric oxide showed drastic upregulation of the PG0893 gene coding for hybrid cluster protein (Hcp), which is a putative hydroxylamine reductase. Although regulation of hcp has been shown to be OxyR dependent in Escherichia coli, here we show that in P. gingivalis its expression is dependent on the Fnr-like regulator designated HcpR. Growth of the isogenic mutant V2807, containing an ermF-ermAM insertion within the hcpR (PG1053) gene, was significantly reduced in the presence of nitrite (P < 0.002) and nitric oxide-generating nitrosoglutathione (GSNO) (P < 0.001), compared to that of the wild-type W83 strain. Furthermore, the upregulation of PG0893 (hcp) was abrogated in V2807 exposed to nitrosative stress. In addition, recombinant HcpR bound DNA containing the hcp promoter sequence, and the binding was hemin dependent. Finally, V2807 was not able to survive with host cells, demonstrating that HcpR plays an important role in P. gingivalis virulence. This work gives insight into the molecular mechanisms of protection against nitrosative stress in P. gingivalis and shows that the regulatory mechanisms differ from those in E. coli.