Functional characterization of murB-porABCD operon for polyamine uptake and peptidoglycan synthesis in Streptococcus suis
Functional characterization of murB-porABCD operon for polyamine uptake and peptidoglycan synthesis in Streptococcus suis
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murB-potABCD 操纵子对猪链球菌多胺摄取和肽聚糖合成的功能表征
DOI：
10.1016/j.micres.2017.11.008
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发表时间：
2018-01-01
影响因子：
6.7
通讯作者：
Zhou, Rui
中科院分区：
文献类型：
--
作者：
Liu, Wanquan;Tan, Meifang;Zhou, Rui
亚精胺（Spd）、精胺（Spm）和腐胺（Put）是细胞内分布最广的多胺，对真核和原核细胞的正常生长和增殖都是必需的。在这项研究中，我们确定了唯一假定的多胺转运系统PotABCD在猪链球菌，一个世界性的人畜共患革兰氏阳性病原体引起致命的感染，在人类和猪。发现S.猪对多胺的吸收以Spd和Spm为主。通过构建potA缺失突变体，我们证实了PotABCD负责多胺的摄取，而PotD与多胺的蛋白结合。四个PotABCD基因与murB共转录，murB是参与肽聚糖（PG）合成的基因。进一步探讨多胺转运系统在维持PG结构中的作用，以了解这种共转录的生物学意义。与野生型相比，突变体ApotA表现出延长的链长度和异常的细胞分裂形态。表型变化归因于ApotA中PG合成和水解相关基因的上调。此外，多胺不仅通过抑制PotA活性作为PotA的反馈调节剂，而且还作为potABCD和参与PG合成的基因的调节剂。本研究揭示了PotABCD在多胺转运中的功能以及多胺在PG合成中的调节作用。这些结果为了解S.猪。
Spermidine (Spd), spermine (Spm), and putrescine (Put), which are the most widely distributed cellular poly amines, are essential for normal growth and multiplication of both eukaryotic and prokaryotic cells. In this study, we identified the only putative polyamine transport system PotABCD in Streptococcus suis, a worldwide zoonotic Gram-positive pathogen causing lethal infections in humans and pigs. It was discovered that S. suis could uptake polyamines preferably Spd and Spm. By constructing a potA deleted mutant, we confirmed that PotABCD was responsible for polyamine uptake, and PotD bound to the protein of polyamines. The four PotABCD genes were co-transcribed with murB, a gene involved in peptidoglycan (PG) synthesis. Furthermore the roles of polyamine transport system in maintaining the PG structure were detected to understand the biological significance of this co-transcription. In contrast to the wild type, the mutant ApotA exhibited elongated chain length and abnormal cell division morphology. Phenotypic changes were attributed to be the up-regulation of genes involved in PG synthesis and hydrolysis in ApotA. Additionally, polyamines functioned not only as feedback regulators of PotA by inhibiting PotA activity but also as regulators on potABCD and genes involved in PG synthesis. This study reveals the functions of PotABCD in polyamine transport and the regulatory roles of polyamines in PG synthesis. Results provide new insights into the machineries contributing to normal growth and cell division of S. suis.