Identification and Characterization of Cyclic Diguanylate Signaling Systems Controlling Rugosity in Vibrio cholerae
Identification and Characterization of Cyclic Diguanylate Signaling Systems Controlling Rugosity in Vibrio cholerae
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DOI：
10.1128/jb.00564-08
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发表时间：
2008-11-01
影响因子：
3.2
通讯作者：
Yildiz, Fitnat H.
中科院分区：
文献类型：
--
作者：
Beyhan, Sinem;Odell, Lindsay S.;Yildiz, Fitnat H.
霍乱弧菌是霍乱的病原体，它可以产生具有增强形成生物膜能力的皱纹变种。粗糙度和生物膜的形成是病原菌在环境中生存和传播的关键，这些过程受环状二鸟苷(c-di-GMP)信号系统的控制。C-di-GMP由二鸟苷环化酶(DGCs)产生，由磷酸二酯酶(PDE)降解。包含GGDEF结构域的蛋白质充当DGC，而包含EAL或HD-Gyp结构域的蛋白质充当PDE。在霍乱弧菌基因组中，有62个基因被预测编码能够调节细胞c-di-GMP浓度的蛋白质。我们以前发现了两种DGC，VpvC和CDgA，它们可以控制平滑和皱纹之间的切换。为了确定与粗糙度有关的其他c-di-GMP信号蛋白，我们对所有编码带有GGDEF和EAL结构域的蛋白的基因进行了框内缺失突变，然后寻找粗糙度发生变化的突变体。在这项研究中，我们发现了两个新的基因cdgG和cdgH，它们与粗糙度控制有关。我们确定，CDgH作为DGC正向调节粗糙度，而CDgG不具有DGC活性，负性调节粗糙度。此外，与cdgG、cdgH和其他控制粗糙度的DGC和PDE的上位性分析表明，cdgG和cdgH与先前发现的c-di-GMP信号蛋白平行地作用于控制霍乱弧菌粗糙度的信号蛋白。我们还确定了含有Pilz结构域的c-di-GMP结合蛋白对粗糙度的贡献最小，这表明在霍乱弧菌中存在额外的c-di-GMP结合蛋白来控制粗糙度。
Vibrio cholerae, the causative agent of the disease cholera, can generate rugose variants that have an increased capacity to form biofilms. Rugosity and biofilm formation are critical for the environmental survival and transmission of the pathogen, and these processes are controlled by cyclic diguanylate (c-di-GMP) signaling systems. c-di-GMP is produced by diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). Proteins that contain GGDEF domains act as DGCs, whereas proteins that contain EAL or HD-GYP domains act as PDEs. In the V. cholerae genome there are 62 genes that are predicted to encode proteins capable of modulating the cellular c-di-GMP concentration. We previously identified two DGCs, VpvC and CdgA, that can control the switch between smooth and rugose. To identify other c-di-GMP signaling proteins involved in rugosity, we generated in-frame deletion mutants of all genes predicted to encode proteins with GGDEF and EAL domains and then searched for mutants with altered rugosity. In this study, we identified two new genes, cdgG and cdgH, involved in rugosity control. We determined that CdgH acts as a DGC and positively regulates rugosity, whereas CdgG does not have DGC activity and negatively regulates rugosity. In addition, epistasis analysis with CdgG, CdgH, and other DGCs and PDEs controlling rugosity revealed that CdgG and CdgH act in parallel with previously identified c-di-GMP signaling proteins to control rugosity in V. cholerae. We also determined that PilZ domain-containing c-di-GMP binding proteins contribute minimally to rugosity, indicating that there are additional c-di-GMP binding proteins controlling rugosity in V. cholerae.