title: Small RNA-induced mRNA degradation achieved through both translation block and activated cleavage.
abstract: Small RNA (sRNA)-induced mRNA degradation occurs through binding of an sRNA to a target mRNA with the concomitant action of the RNA degradosome, which induces an endoribonuclease E (RNase E)-dependent cleavage and degradation of the targeted mRNA. Because many sRNAs bind at the ribosome-binding site (RBS), it is possible that the resulting translation block is sufficient to promote the rapid degradation of the targeted mRNA. Contrary to this mechanism, we report here that the pairing of the sRNA RyhB to the target mRNA sodB initiates mRNA degradation even in the absence of translation on the mRNA target. Remarkably, even though it pairs at the RBS, the sRNA RyhB induces mRNA cleavage in vivo at a distal site located >350 nucleotides (nt) downstream from the RBS, ruling out local cleavage near the pairing site. Both the RNA chaperone Hfq and the RNA degradosome are required for efficient cleavage at the distal site. Thus, beyond translation initiation block, sRNA-induced mRNA cleavage requires several unexpected steps, many of which are determined by structural features of the target mRNA.
authors.affiliation: Department of Biochemistry, RNA Group, University of Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
authors.forename: Karine
authors.initials: K
authors.lastname: Prévost
authors.forename: Guillaume
authors.initials: G
authors.lastname: Desnoyers
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Jacques
authors.forename: François
authors.initials: F
authors.lastname: Lavoie
authors.forename: Eric
authors.initials: E
authors.lastname: Massé
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D004722:Endoribonucleases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D007763:Lac Operon; D008954:Models, Biological; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D030781:Organisms, Genetically Modified; D011117:Polyribonucleotide Nucleotidyltransferase / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D014176:Protein Biosynthesis / Q000187:drug effects* / Q000502:physiology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D020365:RNA Helicases / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012323:RNA Processing, Post-Transcriptional / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D020871:RNA Stability / Q000187:drug effects* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014161:Transduction, Genetic
chemical_list: D001426:Bacterial Proteins; D009097:Multienzyme Complexes; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C111244:degradosome; C087504:SodB protein, Bacteria; D013482:Superoxide Dismutase; D011117:Polyribonucleotide Nucleotidyltransferase; D004722:Endoribonucleases; C022537:ribonuclease E; D020365:RNA Helicases