title: C-terminally truncated derivatives of Escherichia coli Hfq are proficient in riboregulation.
abstract: The prokaryotic Sm-like protein Hfq plays an essential role in the stability and function of trans-encoded small regulatory RNAs in enterobacteria that function in posttranscriptional control by base-pairing with cognate target mRNAs. Hfq associates with both regulatory RNA and target RNA, and its interaction promotes annealing. So far, mutational and structural studies have established that Escherichia coli Hfq contains two separate RNA binding sites that are part of the conserved N-terminal portion of the protein. Moreover, it has been suggested that the nonconserved C-terminal extension of E. coli Hfq might constitute a third RNA interaction surface with specificity for mRNA. However, the role of the C-terminus has not been fully resolved but is clearly important for a complete understanding of Hfq function in posttranscriptional regulation and RNA decay. Here we examined the ability of E. coli Hfq derivatives, consisting of the conserved core and short C-terminal extensions, to support the regulation of rpoS expression and riboregulation by various well-characterized small regulatory RNAs. Our data show that, in all cases tested, the truncated proteins are fully capable of promoting posttranscriptional control, indicating that the C-terminal tail of E. coli Hfq plays a small role or no role in riboregulation.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
authors.forename: Anders Steno
authors.initials: AS
authors.lastname: Olsen
authors.forename: Jakob
authors.initials: J
authors.lastname: Møller-Jensen
authors.forename: Richard G
authors.initials: RG
authors.lastname: Brennan
authors.forename: Poul
authors.initials: P
authors.lastname: Valentin-Hansen
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D001483:Base Sequence; D045647:DNA Glycosylases / Q000235:genetics / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D005798:Genes, Bacterial; D035001:Host Factor 1 Protein / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012323:RNA Processing, Post-Transcriptional; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D029968:Escherichia coli Proteins; C087373:Hfq protein, E coli; D035001:Host Factor 1 Protein; D010446:Peptide Fragments; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011994:Recombinant Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria; D045647:DNA Glycosylases; C061738:mutY adenine glycosylase