Flagellar Basal Body Structural Proteins FlhB, FliM, and FliY Are Required for Flagellar-Associated Protein Expression in Listeria monocytogenes.
Flagellar Basal Body Structural Proteins FlhB, FliM, and FliY Are Required for Flagellar-Associated Protein Expression in Listeria monocytogenes.
复制标题
单核细胞增生李斯特菌中鞭毛相关蛋白表达需要鞭毛基体结构蛋白 FlhB、FliM 和 FliY
DOI：
10.3389/fmicb.2018.00208
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发表时间：
2018
影响因子：
5.2
通讯作者：
Song H
中科院分区：
文献类型：
--
作者：
Cheng C;Wang H;Ma T;Han X;Yang Y;Sun J;Chen Z;Yu H;Hang Y;Liu F;Fang W;Jiang L;Cai C;Song H
单核细胞增生李斯特菌是一种与食物有关的细菌，在世界范围内导致与食物有关的疾病。在单核增生l.s EGD-e基因组中，FlhB、FliM和FliY（分别由lmo0679、lmo0699和lmo0700编码）被注释为推测的鞭毛生物合成因子，但其功能尚不清楚。为了探究FlhB、FliM和FliY是否参与鞭毛李斯特菌的合成，我们利用同源重组策略构建了FlhB、FliM、FliY和其他鞭毛相关基因缺失突变体。然后，我们分析了这些突变菌株的运动性、鞭毛合成和蛋白质表达。在缺乏flhB、fliM或fly的情况下，鞭毛的运动和合成完全被破坏。这些受损的表型在补充菌株CΔflhB， CΔfliM和CΔfliY中完全恢复。鞭毛相关基因flaA、fliM、fly、lmo0695、lmo0698、fliI和fliS的转录水平在flhB、fliM或fly缺失的情况下显著下调。flhB的缺失导致FlaA的表达完全消失，而FliM和fly的表达则降低。在不含fliM或fly的情况下，FlaA的表达完全消失。FlhF和两种鞭毛合成调节因子MogR和GmaR的表达无明显变化。我们首次证明FlhB， FliM和FliY不仅介导李斯特菌的运动，而且还参与调节鞭毛合成。该研究提供了新的见解，增加了我们对FlhB， FliM和fly在单核增生乳杆菌鞭毛III型分泌系统中所起作用的理解。
Listeria monocytogenes is a food-associated bacterium that is responsible for food-related illnesses worldwide. In the L. monocytogenes EGD-e genome, FlhB, FliM, and FliY (encoded by lmo0679, lmo0699, and lmo0700, respectively) are annotated as putative flagella biosynthesis factors, but their functions remain unknown. To explore whether FlhB, FliM, and FliY are involved in Listeria flagella synthesis, we constructed flhB, fliM, fliY, and other flagellar-related gene deletion mutants using a homologous recombination strategy. Then, we analyzed the motility, flagella synthesis, and protein expression of these mutant strains. Motility and flagella synthesis were completely abolished in the absence of flhB, fliM, or fliY. These impaired phenotypes were fully restored in the complemented strains CΔflhB, CΔfliM, and CΔfliY. The transcriptional levels of flagellar-related genes, including flaA, fliM, fliY, lmo0695, lmo0698, fliI, and fliS, were downregulated markedly in the absence of flhB, fliM, or fliY. Deletion of flhB resulted in the complete abolishment of FlaA expression, while it decreased FliM and FliY expression. The expression of FlaA was abolished completely in the absence of fliM or fliY. No significant changes were found in the expression of FlhF and two flagella synthesis regulatory factors, MogR and GmaR. We demonstrate for the first time that FlhB, FliM, and FliY not only mediate Listeria motility, but also are involved in regulating flagella synthesis. This study provides novel insights that increase our understanding of the roles played by FlhB, FliM, and FliY in the flagellar type III secretion system in L. monocytogenes.