Tu Nhan, Lima Amorce, Bandeali Zahra, Anderson Burt
Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
Microb Pathog. 2016 Mar;92:1-10. doi: 10.1016/j.micpath.2015.12.010. Epub 2015 Dec 25.
Bacteria utilize a general stress response system to combat stresses from their surrounding environments. In alpha-proteobacteria, the general stress response uses an alternate sigma factor as the main regulator and incorporates it with a two-component system into a unique regulatory circuit. This system has been described in several alpha-proteobacterial species, including the pathogens Bartonella quintana and Brucella abortus. Most of the studies have focused on characterizing the PhyR anti-anti-sigma factor, the NepR anti-sigma factor, and the alternate sigma factor. However, not enough attention is directed toward studying the role of histidine kinases in the general stress response. Our study identifies the general stress response system in Bartonella henselae, where the gene synteny is conserved and both the PhyR and alternate sigma factor have similar sequence and domain structures with other alpha-proteobacteria. Our data showed that the general stress response genes are up-regulated under conditions that mimic the cat flea vector. Furthermore, we showed that both RpoE and PhyR positively regulate this system and that RpoE also affects transcription of genes encoding heme-binding proteins and the gene encoding the BadA adhesin. Finally, we identified a histidine kinase, annotated as BH13820 that can potentially phosphorylate PhyR.
细菌利用一种通用应激反应系统来应对来自周围环境的压力。在α-变形杆菌中，通用应激反应使用一种替代的σ因子作为主要调节因子，并将其与双组分系统整合到一个独特的调节回路中。该系统已在几种α-变形杆菌物种中得到描述，包括病原体五日热巴尔通体和流产布鲁氏菌。大多数研究都集中在表征PhyR抗抗σ因子、NepR抗σ因子和替代σ因子。然而，对于研究组氨酸激酶在通用应激反应中的作用关注不足。我们的研究确定了亨氏巴尔通体中的通用应激反应系统，其中基因同线性是保守的，并且PhyR和替代σ因子与其他α-变形杆菌具有相似的序列和结构域结构。我们的数据表明，在模拟猫蚤载体的条件下，通用应激反应基因上调。此外，我们表明RpoE和PhyR均正向调节该系统，并且RpoE还影响编码血红素结合蛋白的基因和编码BadA黏附素的基因的转录。最后，我们鉴定出一种组氨酸激酶，注释为BH13820，它可能使PhyR磷酸化。
