URBM-Biology, Université de Namur, Unité de recherche en biologie moléculaire, Belgium.
FEMS Microbiol Rev. 2018 Jul 1;42(4):500-513. doi: 10.1093/femsre/fuy019.
The α-proteobacteria are a fascinating group of free-living, symbiotic and pathogenic organisms, including the Brucella genus, which is responsible for a worldwide zoonosis. One common feature of α-proteobacteria is the presence of a conserved response regulator called CtrA, first described in the model bacterium Caulobacter crescentus, where it controls gene expression at different stages of the cell cycle. Here, we focus on Brucella abortus and other intracellular α-proteobacteria in order to better assess the potential role of CtrA in the infectious context. Comparative genomic analyses of the CtrA control pathway revealed the conservation of specific modules, as well as the acquisition of new factors during evolution. The comparison of CtrA regulons also suggests that specific clades of α-proteobacteria acquired distinct functions under its control, depending on the essentiality of the transcription factor. Other CtrA-controlled functions, for instance motility and DNA repair, are proposed to be more ancestral. Altogether, these analyses provide an interesting example of the plasticity of a regulation network, subject to the constraints of inherent imperatives such as cell division and the adaptations to diversified environmental niches.
α-变形菌是一组具有自由生活、共生和致病特性的迷人生物体，包括布鲁氏菌属，它是造成全世界动物传染病的原因。α-变形菌的一个共同特征是存在一种保守的响应调节剂，称为 CtrA，最初在模式细菌新月柄杆菌中被描述，它在细胞周期的不同阶段控制基因表达。在这里，我们专注于流产布鲁氏菌和其他细胞内 α-变形菌，以便更好地评估 CtrA 在感染环境中的潜在作用。CtrA 控制途径的比较基因组分析揭示了特定模块的保守性，以及在进化过程中获得的新因子。CtrA 调节子的比较还表明，特定的 α-变形菌分支在其控制下获得了独特的功能，这取决于转录因子的必要性。其他 CtrA 控制的功能，例如运动和 DNA 修复，被认为更具原始性。总的来说，这些分析为一个调节网络的可塑性提供了一个有趣的例子，该网络受到内在必然性的限制，如细胞分裂和对多样化的环境小生境的适应。
