The RNA chaperone Hfq is essential for the virulence of Salmonella typhimurium

被引:322
作者
Sittka, Alexandra
Pfeiffer, Verena
Tedin, Karsten
Vogel, Joerg [1 ]
机构
[1] Max Planck Inst Infect Biol, RNA Biol Grp, Berlin, Germany
[2] Free Univ Berlin, Inst Mikrobiol & Tierseuchen, D-1000 Berlin, Germany
关键词
D O I
10.1111/j.1365-2958.2006.05489.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The RNA chaperone, Hfq, plays a diverse role in bacterial physiology beyond its original role as a host factor required for replication of Q beta RNA bacteriophage. In this study, we show that Hfq is involved in the expression and secretion of virulence factors in the facultative intracellular pathogen, Salmonella typhimurium. A Salmonella hfq deletion strain is highly attenuated in mice after both oral and intraperitoneal infection, and shows a severe defect in invasion of epithelial cells and a growth defect in both epithelial cells and macrophages in vitro. Surprisingly, we find that these phenotypes are largely independent of the previously reported requirement of Hfq for expression of the stationary phase sigma factor, RpoS. Our results implicate Hfq as a key regulator of multiple aspects of virulence including regulation of motility and outer membrane protein (OmpD) expression in addition to invasion and intracellular growth. These pleiotropic effects are suggested to involve a network of regulatory small non-coding RNAs, placing Hfq at the centre of post-transcriptional regulation of virulence gene expression in Salmonella. In addition, the hfq mutation appears to cause a chronic activation of the RpoE-mediated envelope stress response which is likely due to a misregulation of membrane protein expression.
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页码:193 / 217
页数:25
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