Bartoli J, My L, Belmudes Lucid, Couté Yohann, Viala J P, Bouveret E
LISM, IMM, Aix-Marseille University, CNRS, Marseille, France.
University Grenoble Alpes, CEA, INSERM, BIG-BGE, Grenoble, France.
J Bacteriol. 2017 Jun 27;199(14). doi: 10.1128/JB.00202-17. Print 2017 Jul 15.
The phospholipid (PL) composition of bacterial membranes varies as a function of growth rate and in response to changes in the environment. While growth adaptation can be explained by biochemical feedback in the PL synthesis pathway, recent transcriptome studies have revealed that the expression of PL synthesis genes can also be tuned in response to various stresses. We previously showed that the BasRS two-component pathway controls the expression of the diacylglycerol kinase gene, , in (A. Wahl, L. My, R. Dumoulin, J. N. Sturgis, and E. Bouveret, Mol Microbiol, 80:1260-1275, 2011, https://doi.org/10.1111/j.1365-2958.2011.07641.x). In this study, we set up a strategy to identify the mutation responsible for the upregulation of observed in the historical mutant and supposedly corresponding to a transcriptional repressor (C. P. Sparrow and J. Raetz, J Biol Chem, 258:9963-9967, 1983). encodes phosphatidylserine synthase, the first step of phosphatidylethanolamine synthesis. We showed that this mutation corresponded to a single nucleotide change in the anti-Shine-Dalgarno sequence of the 16S rRNA encoded by the operon. We further demonstrated that this mutation enhanced the translation of Though this effect appeared to be restricted to PssA among phospholipid synthesis enzymes, it was not specific, as evidenced by a global effect on the production of unrelated proteins. Bacteria adjust the phospholipid composition of their membranes to the changing environment. In addition to enzymatic regulation, stress response regulators control specific steps of the phospholipid synthesis pathway. We wanted to identify a potential regulator controlling the expression of the phosphatidylserine synthase gene. We showed that it was not the previously suggested gene and instead that a mutation in the anti-Shine-Dalgarno sequence of 16S RNA was responsible for an increase in translation. This example underlines the fact that gene expression can be modulated by means other than specific regulatory processes.
细菌膜的磷脂（PL）组成随生长速率变化，并对环境变化作出响应。虽然生长适应性可以通过PL合成途径中的生化反馈来解释，但最近的转录组研究表明，PL合成基因的表达也可以根据各种应激进行调节。我们之前表明，BasRS双组分途径控制二酰基甘油激酶基因在（A. Wahl、L. My、R. Dumoulin、J. N. Sturgis和E. Bouveret，《分子微生物学》，80:1260 - 1275，2011，https://doi.org/10.1111/j.1365 - 2958.2011.07641.x）中的表达。在本研究中，我们制定了一种策略，以鉴定在历史突变体中观察到的导致上调的突变，该突变体被认为对应于一种转录阻遏物（C. P. Sparrow和J. Raetz，《生物化学杂志》，258:9963 - 9967，1983）。编码磷脂酰丝氨酸合酶，这是磷脂酰乙醇胺合成的第一步。我们表明，该突变对应于操纵子编码的16S rRNA的反Shine - Dalgarno序列中的单个核苷酸变化。我们进一步证明，该突变增强了的翻译。尽管这种效应似乎仅限于磷脂合成酶中的PssA，但它并非特异性的，对无关蛋白质产生的全局效应证明了这一点。细菌会根据不断变化的环境调整其膜的磷脂组成。除了酶促调节外，应激反应调节因子控制磷脂合成途径的特定步骤。我们想鉴定一种潜在的调节因子，控制磷脂酰丝氨酸合酶基因的表达。我们表明，它不是先前提出的基因，而是16S RNA的反Shine - Dalgarno序列中的一个突变导致翻译增加。这个例子强调了基因表达可以通过特定调节过程以外的其他方式进行调节这一事实。
