Speiser Yariv, Zusman Tal, Pasechnek Anna, Segal Gil
Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel.
Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv, Israel
Infect Immun. 2017 May 23;85(6). doi: 10.1128/IAI.00121-17. Print 2017 Jun.
The nitrogen phosphotransferase system (PTS) is a regulatory cascade present in many bacteria, where it controls different functions. This system is usually composed of three basic components: enzyme I (EI), NPr, and EIIA (encoded by the , , and genes, respectively). In , as well as in many other species, the EIIA component is missing. However, we found that deletion mutations in both and are partially attenuated for intracellular growth. Furthermore, these two PTS components were found to be required for maximal expression of effector-encoding genes regulated by the transcriptional activator PmrA. Genetic analyses which include the construction of single and double deletion mutants and overexpression of wild-type and mutated forms of EI, NPr, and PmrA indicated that the PTS components affect the expression of PmrA-regulated genes via PmrA and independently from PmrB and that EI and NPr are part of the same cascade and require their conserved histidine residues in order to function. Furthermore, expression of the EII component in resulted in a reduction in the levels of expression of PmrA-regulated genes which was completely dependent on the PTS components and the EII conserved histidine residue. Moreover, reconstruction of the PTS indicated that EI is phosphorylated by phosphoenolpyruvate (PEP) and transfers its phosphate to NPr. Our results demonstrate that the incomplete PTS is functional and involved in the expression of effector-encoding genes regulated by PmrA.
氮磷酸转移酶系统（PTS）是许多细菌中存在的一种调节级联反应，它控制着不同的功能。该系统通常由三个基本成分组成：酶I（EI）、NPr和EIIA（分别由、和基因编码）。在中，以及在许多其他物种中，缺少EIIA成分。然而，我们发现和中的缺失突变在细胞内生长方面部分减弱。此外，发现这两个PTS成分是由转录激活因子PmrA调控的效应器编码基因最大表达所必需的。包括构建单缺失和双缺失突变体以及EI、NPr和PmrA的野生型和突变形式的过表达在内的遗传分析表明，PTS成分通过PmrA影响PmrA调控基因的表达，且独立于PmrB，并且EI和NPr属于同一级联反应，需要其保守的组氨酸残基才能发挥作用。此外，在中表达EII成分导致PmrA调控基因的表达水平降低，这完全依赖于PTS成分和EII保守的组氨酸残基。此外，对PTS的重建表明，EI被磷酸烯醇丙酮酸（PEP）磷酸化，并将其磷酸基团转移到NPr。我们的结果表明，不完整的PTS具有功能，并参与由PmrA调控的效应器编码基因的表达。
