The Sm-like RNA chaperone Hfq mediates transcription antitermination at Rho-dependent terminators.

Abstract : In Escherichia coli, the essential motor protein Rho promotes transcription termination in a tightly controlled manner that is not fully understood. Here, we show that the general post-transcriptional regulatory protein Hfq associates with Rho to regulate Rho function. The Hfq:Rho complex can be further stabilized by RNA bridging both factors in a configuration that inhibits the ATP hydrolysis and duplex unwinding activities of Rho and that mediates transcription antitermination at Rho-dependent terminators in vitro and in vivo. Antitermination at a prototypical terminator (λtR1) requires Hfq binding to an A/U-rich transcript region directly upstream from the terminator. Antitermination is modulated by trans-acting factors (NusG or nucleic acid competitors) that affect Hfq association with Rho or RNA. These data unveil a new Hfq function and a novel transcription regulatory mechanism with potentially important implications for bacterial RNA metabolism, gene silencing, and pathogenicity.
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Submitted on : Wednesday, July 25, 2012 - 2:40:57 PM
Last modification on : Wednesday, July 24, 2019 - 10:12:01 AM

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Makhlouf Rabhi, Olivier Espéli, Annie Schwartz, Bastien Cayrol, a Rachid Rahmouni, et al.. The Sm-like RNA chaperone Hfq mediates transcription antitermination at Rho-dependent terminators.. EMBO Journal, EMBO Press, 2011, 30 (14), pp.2805-16. ⟨10.1038/emboj.2011.192⟩. ⟨hal-00720713⟩

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