Department of Ecophysiology, Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
PLoS One. 2011;6(9):e23440. doi: 10.1371/journal.pone.0023440. Epub 2011 Sep 12.
The BarA/UvrY two-component system is well conserved in species of the γ-proteobacteria and regulates numerous processes predominantly by controlling the expression of a subset of noncoding small RNAs. In this study, we identified and characterized the BarA/UvrY two-component system in the gammaproteobacterium Shewanella oneidensis MR-1. Functional interaction of sensor kinase BarA and the cognate response regulator UvrY was indicated by in vitro phosphotransfer studies. The expression of two predicted small regulatory RNAs (sRNAs), CsrB1 and CsrB2, was dependent on UvrY. Transcriptomic analysis by microarrays revealed that UvrY is a global regulator and directly or indirectly affects transcript levels of more than 200 genes in S. oneidensis. Among these are genes encoding key enzymes of central carbon metabolism such as ackA, aceAB, and pflAB. As predicted of a signal transduction pathway that controls aspects of central metabolism, mutants lacking UvrY reach a significantly higher OD than the wild type during aerobic growth on N-acetylglucosamine (NAG) while under anaerobic conditions the mutant grew more slowly. A shorter lag phase occurred with lactate as carbon source. In contrast, significant growth phenotypes were absent in complex medium. Based on these studies we hypothesize that, in S. oneidensis MR-1, the global BarA/UvrY/Csr regulatory pathway is involved in central carbon metabolism processes.
γ-变形菌中广泛存在的 BarA/UvrY 双组分系统主要通过调控一组非编码小 RNA 的表达来调控多种生理过程。在本研究中，我们鉴定并分析了γ-变形菌希瓦氏菌属（Shewanella oneidensis）MR-1 中的 BarA/UvrY 双组分系统。体外磷酸转移研究表明传感器激酶 BarA 和同源响应调控蛋白 UvrY 之间存在功能相互作用。两个预测的小调控 RNA（sRNA）CsrB1 和 CsrB2 的表达依赖于 UvrY。通过微阵列进行的转录组分析表明，UvrY 是一个全局调控因子，直接或间接地影响希瓦氏菌属中超过 200 个基因的转录水平。其中包括编码关键酶的基因，如 ackA、aceAB 和 pflAB，这些酶参与中心碳代谢。作为控制中心代谢的信号转导途径的预测，与野生型相比，缺乏 UvrY 的突变体在有氧条件下利用 N-乙酰葡糖胺（NAG）生长时达到更高的 OD 值，而在厌氧条件下突变体生长较慢。以乳酸为碳源时，潜伏期更短。相比之下，在复杂培养基中不存在明显的生长表型。基于这些研究，我们假设在希瓦氏菌属 MR-1 中，全局的 BarA/UvrY/Csr 调控途径参与了中心碳代谢过程。
