Overexpression of MazFSa in Staphylococcus aureus Induces Bacteriostasis by Selectively Targeting mRNAs for Cleavage
Overexpression of MazFSa in Staphylococcus aureus Induces Bacteriostasis by Selectively Targeting mRNAs for Cleavage
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DOI：
10.1128/jb.00907-08
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发表时间：
2009-04-01
影响因子：
3.2
通讯作者：
Cheung, Ambrose L.
中科院分区：
文献类型：
--
作者：
Fu, Zhibiao;Tamber, Sandeep;Cheung, Ambrose L.
染色体编码的毒素-抗毒素（TA）位点在细菌生理中的作用一直存在争议，毒素被认为是抑菌的诱导剂或程序性细胞死亡（PCD）的介质。我们在这里报道，来自金黄色葡萄球菌的TA模块的毒素MazF（Sa）的异位表达导致CFU计数迅速减少，但在MazF（Sa）诱导后，通过Syto - 9和碘化丙啶染色的差异确定，大多数细胞仍然存活。这一发现表明，毒素MazF（Sa）诱导细胞停滞而不是细胞死亡。我们还发现，MazF（Sa）在体内选择性地切割细胞mrna，在MazF（Sa）诱导的细胞中避免“重要”转录物，如recA、gyrB和sarA mrna，而这三种mrna可以在体外切割。西北印迹结果显示sarA和recA mrna都与一种假定的rna结合蛋白强烈结合。这些数据表明，金黄色葡萄球菌可能通过rna结合蛋白在体内表达MazF（Sa）时保护选择性mRNA而经历停滞。
The role of chromosomally encoded toxin-antitoxin (TA) loci in bacterial physiology has been under debate, with the toxin proposed as either an inducer of bacteriostasis or a mediator of programmed cell death (PCD). We report here that ectopic expression of MazF(Sa), a toxin of the TA module from Staphylococcus aureus, led to a rapid decrease in CFU counts but most cells remained viable as determined by differential Syto 9 and propidium iodide staining after MazF(Sa) induction. This finding suggested that the toxin MazF(Sa) induced cell stasis rather than cell death. We also showed that MazF(Sa) selectively cleaves cellular mRNAs in vivo, avoiding "important" transcripts such as recA, gyrB, and sarA mRNAs in MazF(Sa)-induced cells, while these three mRNAs can be cleaved in vitro. The results of Northwestern blotting showed that both sarA and recA mRNAs bind strongly to a putative RNA-binding protein. These data suggest that S. aureus likely undergoes stasis by protecting selective mRNA with RNA-binding proteins upon the expression of MazF(Sa) in vivo.