An Essential Regulatory System Originating from Polygenic Transcriptional Rewiring of PhoP-PhoQ of Xanthomonas campestris
An Essential Regulatory System Originating from Polygenic Transcriptional Rewiring of PhoP-PhoQ of Xanthomonas campestris
复制标题
源自野油菜黄单胞菌PhoP-PhoQ多基因转录重排的重要调控系统
DOI：
10.1534/genetics.117.200204
复制
发表时间：
2017-08-01
期刊：
影响因子：
3.3
通讯作者：
Qian, Wei
中科院分区：
文献类型：
--
作者：
Peng, Bao-Yu;Pan, Yue;Qian, Wei
重要的调控基因如何起源和进化是有趣的，因为这些基因的突变不仅导致生物体的致命性，而且还具有多效性效应，因为它们控制多个下游基因的表达。因此，必需的调控基因的进化不仅由其自身序列的遗传变异决定，而且还由下游基因的生物学功能和调控的分子机制决定。为了了解基本的调控基因的起源，需要对完整的调控级联进行实验解剖。在这里，我们提供的遗传证据表明，PhoP-PhoQ是一个必不可少的双组分信号转导系统的革兰氏阴性细菌野油菜黄单胞菌，但它的直系同源物在其他细菌属于变形菌是不必要的。突变、生化和染色质免疫沉淀以及高通量测序分析表明，X. campestris及其近亲铜绿假单胞菌是可替换的，并且转录因子PhoP的共有结合基序也是高度保守的。X.油菜通过直接结合顺式调节元件（克雷斯）来调节许多必需的结构基因的转录;然而，这些克雷斯缺乏铜绿假单胞菌中的正向必需的结构基因，因此PhoPPae与这些下游必需基因之间的调节关系是分离的。我们的研究结果表明，通过转录因子CRE重新布线的关键结构基因的调节蛋白的招聘是一个驱动力的起源和功能的分歧，必要的，调节基因。
How essential, regulatory genes originate and evolve is intriguing because mutations of these genes not only lead to lethality in organisms, but also have pleiotropic effects since they control the expression of multiple downstream genes. Therefore, the evolution of essential, regulatory genes is not only determined by genetic variations of their own sequences, but also by the biological function of downstream genes and molecular mechanisms of regulation. To understand the origin of essential, regulatory genes, experimental dissection of the complete regulatory cascade is needed. Here, we provide genetic evidences to reveal that PhoP-PhoQ is an essential two-component signal transduction system in the gram-negative bacterium Xanthomonas campestris, but that its orthologs in other bacteria belonging to Proteobacteria are nonessential. Mutational, biochemical, and chromatin immunoprecipitation together with high-throughput sequencing analyses revealed that phoP and phoQ of X. campestris and its close relative Pseudomonas aeruginosa are replaceable, and that the consensus binding motifs of the transcription factor PhoP are also highly conserved. PhoPXcc in X. campestris regulates the transcription of a number of essential, structural genes by directly binding to cis-regulatory elements (CREs); however, these CREs are lacking in the orthologous essential, structural genes in P. aeruginosa, and thus the regulatory relationships between PhoPPae and these downstream essential genes are disassociated. Our findings suggested that the recruitment of regulatory proteins by critical structural genes via transcription factor-CRE rewiring is a driving force in the origin and functional divergence of essential, regulatory genes.