INRAE, Micalis, AgroParisTech, Université Paris-Saclay, F-78352, Jouy-en-Josas, France.
Present address: IBENS Institute, CNRS UMR8197, Inserm U1024, Paris, France.
Microbiology (Reading). 2020 Apr;166(4):398-410. doi: 10.1099/mic.0.000883. Epub 2020 Jan 28.
The transcriptional regulator PlcR, its cognate cell-cell signaling heptapeptide PapR, and the oligopeptide permease OppABCDF, required for PapR import, form a quorum-sensing system that controls the expression of virulence factors in and species. In strain ATCC 14579, the transcriptional regulator PlcRa activates the expression of gene, which encodes an AbrB-like transcriptional regulator involved in cysteine biosynthesis. PlcRa is a structural homolog of PlcR: in particular, its C-terminal TPR peptide-binding domain could be similarly arranged as in PlcR. The signaling peptide of PlcRa is not known. As PlcRa is a PlcR-like protein, the cognate PapR peptide (ADLPFEF) is a relevant candidate to act as a signaling peptide for PlcRa activation. Also, the putative PapRa peptide (CSIPYEY), encoded by the gene adjacent to the gene, is a relevant candidate as addition of synthetic PapRa induces a dose-dependent increase of expression. To address the issue of peptide selectivity of PlcRa, the role of PapR and PapRa peptides in PlcRa activity was investigated in 407 strain, by genetic and functional complementation analyses. A transcriptional fusion between the promoter of and was used to monitor the PlcRa activity in various genetic backgrounds. We demonstrated that PapR was necessary and sufficient for PlcRa activity. We showed that synthetic PapRs from pherogroups II, III and IV and synthetic PapRa were able to trigger expression, suggesting that PlcRa is less selective than PlcR. Lastly, the mode of binding of PlcRa was addressed using an approach. Overall, we report a new role for PapR as a signaling peptide for PlcRa activity and show a functional link between PlcR and PlcRa regulons in .
转录调控因子 PlcR、其同源细胞间信号七肽 PapR 和寡肽转运体 OppABCDF，这些是 PapR 导入所必需的，共同构成了一个群体感应系统，控制 和 种的毒力因子的表达。在 菌株 ATCC 14579 中，转录调控因子 PlcRa 激活 基因的表达，该基因编码一种参与半胱氨酸生物合成的 AbrB 样转录调控因子。PlcRa 是 PlcR 的结构同源物：特别是，其 C 端 TPR 肽结合结构域可以与 PlcR 相似地排列。PlcRa 的信号肽尚不清楚。由于 PlcRa 是 PlcR 样蛋白，因此同源的 PapR 肽（ADLPFEF）是作为 PlcRa 激活的信号肽的相关候选物。此外，由 基因相邻的 基因编码的假定 PapRa 肽（CSIPYEY）也是相关候选物，因为添加合成的 PapRa 会诱导 表达的剂量依赖性增加。为了解决 PlcRa 肽选择性的问题，通过遗传和功能互补分析研究了 PapR 和 PapRa 肽在 PlcRa 活性中的作用，在 407 株中。使用 与 之间的启动子的转录融合来监测各种遗传背景下的 PlcRa 活性。我们证明了 PapR 是 PlcRa 活性所必需和充分的。我们表明，来自菌毛群 II、III 和 IV 的合成 PapRs 和合成 PapRa 能够触发 表达，表明 PlcRa 比 PlcR 的选择性更低。最后，使用 方法解决了 PlcRa 结合模式的问题。总体而言，我们报告了 PapR 作为 PlcRa 活性的信号肽的新作用，并显示了 PlcR 和 PlcRa 调控子在 中的功能联系。
