title: Two novel members of the LhrC family of small RNAs in Listeria monocytogenes with overlapping regulatory functions but distinctive expression profiles.
abstract: Multicopy small RNAs (sRNAs) have gained recognition as an important feature of bacterial gene regulation. In the human pathogen Listeria monocytogenes, 5 homologous sRNAs, called LhrC1-5, control gene expression by base pairing to target mRNAs though 3 conserved UCCC motifs common to all 5 LhrCs. We show here that the sRNAs Rli22 and Rli33-1 are structurally and functionally related to LhrC1-5, expanding the LhrC family to 7 members, which makes it the largest multicopy sRNA family reported so far. Rli22 and Rli33-1 both contain 2 UCCC motifs important for post-transcriptional repression of 3 LhrC target genes. One such target, oppA, encodes a virulence-associated oligo-peptide binding protein. Like LhrC1-5, Rli22 and Rli33-1 employ their UCCC motifs to recognize the Shine-Dalgarno region of oppA mRNA and prevent formation of the ribosomal complex, demonstrating that the 7 sRNAs act in a functionally redundant manner. However, differential expression profiles of the sRNAs under infection-relevant conditions suggest that they might also possess non-overlapping functions. Collectively, this makes the LhrC family a unique case for studying the purpose of sRNA multiplicity in the context of bacterial virulence.
authors.affiliation: a Department of Biochemistry and Molecular Biology , University of Southern Denmark , Odense , Denmark.
authors.forename: Maria Storm
authors.initials: MS
authors.lastname: Mollerup
authors.affiliation: a Department of Biochemistry and Molecular Biology , University of Southern Denmark , Odense , Denmark.
authors.forename: Joseph Andrew
authors.initials: JA
authors.lastname: Ross
authors.affiliation: b Architecture et Réactivité de l´ARN, Université de Strasbourg, CNRS, IBMC , Strasbourg , France.
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Helfer
authors.affiliation: a Department of Biochemistry and Molecular Biology , University of Southern Denmark , Odense , Denmark.
authors.forename: Kristine
authors.initials: K
authors.lastname: Meistrup
authors.affiliation: b Architecture et Réactivité de l´ARN, Université de Strasbourg, CNRS, IBMC , Strasbourg , France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Romby
authors.affiliation: a Department of Biochemistry and Molecular Biology , University of Southern Denmark , Odense , Denmark.
authors.forename: Birgitte Haahr
authors.initials: BH
authors.lastname: Kallipolitis
mesh_terms: D020029:Base Pairing; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D008089:Listeria monocytogenes / Q000235:genetics*; D005810:Multigene Family; D009690:Nucleic Acid Conformation; D059372:Nucleotide Motifs; D011485:Protein Binding; D034622:RNA Interference; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D058727:RNA, Small Untranslated / Q000737:chemistry / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism; D059467:Transcriptome
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger; D058727:RNA, Small Untranslated
keywords: Antisense; Listeria monocytogenes; multiplicity; post-transcriptional regulation; sRNAs