FliA expression analysis and influence of the regulatory proteins RpoN, FleQ and FliA on virulence and in vivo fitness in Legionella pneumophila
FliA expression analysis and influence of the regulatory proteins RpoN, FleQ and FliA on virulence and in vivo fitness in Legionella pneumophila
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DOI：
10.1007/s00203-012-0833-y
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发表时间：
2012-08
影响因子：
2.8
通讯作者：
Tino Schulz;Kerstin Rydzewski;E. Schunder;Gudrun Holland;N. Bannert;K. Heuner
中科院分区：
文献类型：
--
作者：
Tino Schulz;Kerstin Rydzewski;E. Schunder;Gudrun Holland;N. Bannert;K. Heuner
在嗜肺军团菌中，鞭毛的调节和毒力特征的表达是相关的。 FleQ、RpoN 和 FliA 是鞭毛调节子的主要调节因子。我们在这里证明了提到的所有三种调节蛋白（FleQ、RpoN 和 FliA）对于 L 的完全体内适应性是必需的。嗜肺军团菌 Corby 和 Paris。在本研究中，我们从mRNA水平到蛋白质翻译水平阐明了FleQ对于fliA表达的作用。 FleQ增强fliA表达，但FleQ和RpoN对于基础表达不是必需的。此外，我们还确定了 offliAinL 的起始位点。 pneumophilaand 发现了位于上游的推定 σ70 启动子元件。 ΔfleQ或ΔrpoN突变株中的起始位点不受影响。我们证明，Corby 菌株和 Paris 菌株之间的 offliA 调控没有显着差异，但指数期 FleQ 依赖性诱导 offliA 转录在 Paris 菌株中比 Corby 菌株更强。此外，我们首次通过电镜观察发现无鞭毛的ΔfliA和ΔfliD突变株的极点存在直钩，表明这些菌株存在完整的基体。
InLegionella pneumophila, the regulation of the flagellum and the expression of virulence traits are linked. FleQ, RpoN and FliA are the major regulators of the flagellar regulon. We demonstrated here that all three regulatory proteins mentioned (FleQ, RpoN and FliA) are necessary for full in vivo fitness ofL. pneumophilastrains Corby and Paris. In this study, we clarified the role of FleQ forfliAexpression from the level of mRNA toward protein translation. FleQ enhancedfliAexpression, but FleQ and RpoN were not necessary for basal expression. In addition, we identified the initiation site offliAinL. pneumophilaand found a putative σ70promoter element localized upstream. The initiation site was not influenced in the ΔfleQor ΔrpoNmutant strain. We demonstrated that there is no significant difference in the regulation offliAbetween strains Corby and Paris, but the FleQ-dependent induction offliAtranscription in the exponential phase is stronger in strain Paris than in strain Corby. In addition, we showed for the first time the presence of a straight hook at the pole of the non-flagellated ΔfliAand ΔfliDmutant strains by electron microscopy, indicating the presence of an intact basal body in these strains.