The role of Hfq in virulence of Shigella flexneri

The role of Hfq in virulence of Shigella flexneri

Sanjay K Gupta, Kai Papenfort & Jörg Vogel

RNA Biology Group, Institute of Molecular Infection Biology, University of Wuerzburg, Wuerzburg Germany.

The Hfq protein is a well-known post-transcriptional regulator with documented functions in virulence of numerous bacterial pathogens (1). At the molecular level, Hfq is required for the stability of most small regulatory RNAs (sRNAs) interactions with target mRNAs.

In this study we aim to elucidate the role of Hfq in Shigella flexneri, a gram negative rod shaped bacteria and the causative agent of dysentery in humans. Similar to other enterobacterial pathogens, the virulence of S. flexneri strongly relies on horizontally acquired genomic elements for invasion of and survival inside the host cell. Specifically, a transmittable plasmid, known as the Shigella "virulence plasmid" is essential for infectivity (2).

Our present data suggests that aside from having a global effect on cellular morphology and replication of S. flexneri, Hfq is important for maintaining the "virulence plasmid"; in other words, Hfq seems to facilitate cross-talk between the plasmid and the core genome. To elucidate the function of Hfq in this interplay, we have been performing co-immunoprecipitation and RNA-seq experiments using chromosomally tagged Hfq protein (3), comparing strains with or without the "virulence plasmid". We expect that this approach will allow us to identify infection-relevant, Hfq-bound RNAs originating from the "virulence plasmid" and might provide insights into the global patterns of Hfq-binding affected by horizontally acquired genomic elements.

References: 1. Chao, Y. and Vogel, J. (2010) The role of Hfq in bacterial pathogens. Curr Opin Microbiol, 13, 24-33. 2. Schroeder, G.N. and Hilbi, H. (2008) Molecular pathogenesis of Shigella spp.: controlling host cell signaling, invasion, and death by type III secretion. Clin Microbiol Rev, 21, 134-156. 3. Sittka 08