The OxyS regulatory RNA represses rpoS translation and binds the Hfq (HF-I) protein

Abstract

The OxyS regulatory RNA integrates the adaptive response to hydrogen peroxide with other cellular stress responses and protects against DNA damage. Among the OxyS targets is the rpoS-encoded σ s subunit of RNA polymerase. σ s is a central regulator of genes induced by osmotic stress, starvation and entry into stationary phase. We examined the mechanism whereby OxyS represses rpoS expression and found that the OxyS RNA inhibits translation of the rpoS message. This repression is dependent on the hfqencoded RNA-binding protein (also denoted host factor I, HF-I). Co-immunoprecipitation and gel mobility shift experiments revealed that the OxyS RNA binds Hfq, suggesting that OxyS represses rpoS translation by altering Hfq activity.

Coupled degradation of a small regulatory RNA and its mRNA targets in Escherichia coli

“…DsrA also acts negatively on hns translation and message stability (Lease and Belfort 2000). OxyS acts negatively on the translation of the fhlA and rpoS regulatory genes Zhang et al 1998). Both of these small RNAs are relatively stable (half-lives: OxyS, 15-30 min; Altuvia et al 1997;Zhang et al 2002); DsrA, 20 min Sledjeski et al 2001).…”

Structure of Escherichia coli Hfq bound to polyriboadenylate RNA

“…Moreover, the functional importance of such Hfq-binding (A-R-N) i tracts within mRNA coding sequences (CDS) is likely, and supported by the recent finding that the Hfq-associated sRNA, MicC, targets the CDS of ompD mRNA and that the target site, which contains an AACAAA stretch, is bound (albeit weakly) by Hfq (58). Finally, a simple search of the E. coli genome for poly(A-R-N) i sequences (http://genolist.pasteur.fr/Colibri/ using ''Search Pattern'') revealed 69 unique (A-R-N) 5 tracts in the mRNA translation initiation regions (spanning nucleotides Ϫ100 to ϩ1) with the average start site at position Ϫ44 and 14 (Ϸ20%) overlapping the Shine-Dalgarno (SD) site (Ϫ23 to ϩ1). A similar search for (A-R-N) 4 tracts yielded 394 unique examples with 72 (Ϸ18%) overlapping the SD box and an average start site at nucleotide Ϫ39.…”

“…Hfq binds to AU-rich stretches near stem loop structures of small noncoding RNAs (sRNA) and their target mRNAs to facilitate the annealing of their trans-encoded complementary sequences and hence to effect message-specific translational regulation (4)(5)(6)(7)(8). Thus, Hfq has been called an ''RNA chaperone.''…”

Peroxide‐Sensing Transcriptional Regulators in Bacteria

“…The OxyR regulon of Escherichia coli is comprised of over 20 genes, including genes involved in H 2 O 2 detoxification (katE, ahpCF), heme biosynthesis (hemH), reductant supply (grxA, gor, trxC), thiol-disulfide isomerization (dsbG), Fe-S center repair (sufA-E, sufS), iron binding (yaaA), repression of iron import systems (fur), and manganese import (71,124,125). OxyR also upregulates the expression of OxyS, a small regulatory RNA that integrates peroxide stress with general stress pathways (34,122). Although there are significant differences, the OxyR regulons of other organisms tend to include similar classes of genes (39,82,96,104,116).…”