RRC ID 35315
Author Vecerek B, Beich-Frandsen M, Resch A, Bläsi U.
Title Translational activation of rpoS mRNA by the non-coding RNA DsrA and Hfq does not require ribosome binding.
Journal Nucleic Acids Res.
Abstract At low temperature, translational activation of rpoS mRNA, encoding the stationary phase sigma-factor, sigma(S), involves the small regulatory RNA (sRNA) DsrA and the RNA chaperone Hfq. The Hfq-mediated DsrA-rpoS interaction relieves an intramolecular secondary structure that impedes ribosome access to the rpoS ribosome binding site. In addition, DsrA/rpoS duplex formation creates an RNase III cleavage site within the duplex. Previous biochemical studies suggested that DsrA and Hfq associate with the 30S ribosomal subunit protein S1, which implied a role for the ribosome in sRNA-mediated post-transcriptional regulation. Here, we show by ribosome profiling that Hfq partitions with the cytoplasmic fraction rather than with 30S subunits. Besides, by employing immunological techniques, no evidence for a physical interaction between Hfq and S1 was obtained. Similarly, in vitro studies did not reveal a direct interaction between DsrA and S1. By employing a ribosome binding deficient rpoS mRNA, and by using the RNase III clevage in the DsrA/rpoS duplex as a diagnostic marker, we provide in vivo evidence that the Hfq-mediated DsrA/rpoS interaction, and consequently the structural changes in rpoS mRNA precede ribosome binding. These data suggest a simple mechanistic model in which translational activation by DsrA provides a translationally competent rpoS mRNA to which 30S subunits can readily bind.
Volume 38(4)
Pages 1284-93
Published 2010-3
DOI 10.1093/nar/gkp1125
PII gkp1125
PMID 19969548
PMC PMC2831331
MeSH Bacterial Proteins / biosynthesis Bacterial Proteins / genetics* Blotting, Western Cytoplasm / chemistry Escherichia coli / genetics Escherichia coli / metabolism Escherichia coli Proteins / analysis Escherichia coli Proteins / biosynthesis Escherichia coli Proteins / genetics* Escherichia coli Proteins / metabolism Gene Expression Regulation, Bacterial* Host Factor 1 Protein / analysis Host Factor 1 Protein / metabolism* Protein Biosynthesis* RNA, Messenger / chemistry RNA, Small Untranslated RNA, Untranslated / metabolism* Ribosomal Proteins / metabolism Ribosome Subunits, Small, Bacterial / metabolism Ribosomes / metabolism Sigma Factor / biosynthesis Sigma Factor / genetics*
IF 11.561
Times Cited 24
Prokaryotes E. coli JW4130-KC JW5437-KC