Dataset Information

Dynamic Refolding of OxyS sRNA by the Hfq RNA Chaperone.

ABSTRACT: The Sm protein Hfq chaperones small non-coding RNAs (sRNAs) in bacteria, facilitating sRNA regulation of target mRNAs. Hfq acts in part by remodeling the sRNA and mRNA structures, yet the basis for this remodeling activity is not understood. To understand how Hfq remodels RNA, we used single-molecule Förster resonance energy transfer (smFRET) to monitor conformational changes in OxyS sRNA upon Hfq binding. The results show that E. coli Hfq first compacts OxyS, bringing its 5' and 3 ends together. Next, Hfq destabilizes an internal stem-loop in OxyS, allowing the RNA to adopt a more open conformation that is stabilized by a conserved arginine on the rim of Hfq. The frequency of transitions between compact and open conformations depend on interactions with Hfqs flexible C-terminal domain (CTD), being more rapid when the CTD is deleted, and slower when OxyS is bound to Caulobacter crescentus Hfq, which has a shorter and more stable CTD than E. coli Hfq. We propose that the CTDs gate transitions between OxyS conformations that are stabilized by interaction with one or more arginines. These results suggest a general model for how basic residues and intrinsically disordered regions of RNA chaperones act together to refold RNA.

SUBMITTER: Cai H

PROVIDER: S-EPMC10044511 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Publications

Dynamic Refolding of OxyS sRNA by the Hfq RNA Chaperone.

Cai Huahuan H Roca Jorjethe J Zhao Yu-Fen YF Woodson Sarah A SA

Journal of molecular biology 20220804 18

The Sm protein Hfq chaperones small non-coding RNAs (sRNAs) in bacteria, facilitating sRNA regulation of target mRNAs. Hfq acts in part by remodeling the sRNA and mRNA structures, yet the basis for this remodeling activity is not understood. To understand how Hfq remodels RNA, we used single-molecule Förster resonance energy transfer (smFRET) to monitor conformational changes in OxyS sRNA upon Hfq binding. The results show that E. coli Hfq first compacts OxyS, bringing its 5' and 3 ends together ...[more]

PMID: 35934049

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Project description:Significance Hfq is a key posttranscriptional regulator that modulates base-pairing interactions between sRNAs and their target mRNAs. Although there are more than 100 different sRNAs in Pseudomonas aeruginosa, information on their regulatory targets was available for only a few. Here, we identify the targets of 89 Hfq-associated sRNAs in this important opportunistic pathogen. Furthermore, we show that a single sRNA called PhrS dominates the RNA–RNA interaction landscape in this organism by pairing with approximately 800 targets. Our study therefore provides insight into the potential regulatory roles for many sRNAs in P. aeruginosa and identifies an sRNA with an acutely outsized influence on the RNA–RNA interactions occurring on Hfq in this bacterium. The RNA chaperone Hfq plays important regulatory roles in many bacteria by facilitating the base pairing between small RNAs (sRNAs) and their cognate mRNA targets. In the gram-negative opportunistic pathogen Pseudomonas aeruginosa, over a hundred putative sRNAs have been identified but for most, their regulatory targets remained unknown. Using RIL-seq with Hfq in P. aeruginosa, we identified the mRNA targets for dozens of previously known and unknown sRNAs. Strikingly, hundreds of the RNA–RNA interactions we discovered involved PhrS. This sRNA was thought to mediate its effects by pairing with a single target mRNA and regulating the abundance of the transcription regulator MvfR required for the synthesis of the quorum sensing signal PQS. We present evidence that PhrS controls many transcripts by pairing with them directly and employs a two-tiered mechanism for governing PQS synthesis that involves control of an additional transcription regulator called AntR. Our findings in P. aeruginosa expand the repertoire of targets for previously known sRNAs, reveal potential regulatory targets for previously unknown sRNAs, and suggest that PhrS may be a keystone sRNA with the ability to pair with an unusually large number of transcripts in this organism.

Dataset Information

Dynamic Refolding of OxyS sRNA by the Hfq RNA Chaperone.

Publications

Dynamic Refolding of OxyS sRNA by the Hfq RNA Chaperone.

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