title: Silencing of natural transformation by an RNA chaperone and a multitarget small RNA.
abstract: A highly conserved DNA uptake system allows many bacteria to actively import and integrate exogenous DNA. This process, called natural transformation, represents a major mechanism of horizontal gene transfer (HGT) involved in the acquisition of virulence and antibiotic resistance determinants. Despite evidence of HGT and the high level of conservation of the genes coding the DNA uptake system, most bacterial species appear non-transformable under laboratory conditions. In naturally transformable species, the DNA uptake system is only expressed when bacteria enter a physiological state called competence, which develops under specific conditions. Here, we investigated the mechanism that controls expression of the DNA uptake system in the human pathogen Legionella pneumophila We found that a repressor of this system displays a conserved ProQ/FinO domain and interacts with a newly characterized trans-acting sRNA, RocR. Together, they target mRNAs of the genes coding the DNA uptake system to control natural transformation. This RNA-based silencing represents a previously unknown regulatory means to control this major mechanism of HGT. Importantly, these findings also show that chromosome-encoded ProQ/FinO domain-containing proteins can assist trans-acting sRNAs and that this class of RNA chaperones could play key roles in post-transcriptional gene regulation throughout bacterial species.
authors.affiliation: CNRS UMR5240, Microbiologie Adaptation et Pathogénie, 69622 Villeurbanne, France; Université Claude Bernard Lyon 1, 69100 Villeurbanne, France; International Center for Infectiology Research (CIRI), International Center for Infectiology Research, Université de Lyon, 69364 Lyon, France; INSERM U1111, 69364 Lyon, France; Ecole Normale Supérieure de Lyon, 69364 Lyon, France; Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, 69364 Lyon, France; CNRS UMR5308, 69007 Lyon, France;
authors.forename: Laetitia
authors.initials: L
authors.lastname: Attaiech
authors.affiliation: CNRS UMR5240, Microbiologie Adaptation et Pathogénie, 69622 Villeurbanne, France; Université Claude Bernard Lyon 1, 69100 Villeurbanne, France;
authors.forename: Aïda
authors.initials: A
authors.lastname: Boughammoura
authors.affiliation: Laboratoire de Biométrie et Biologie Evolutive, CNRS UMR5558, Université de Lyon, Université Lyon 1, F-69622 Villeurbanne, France;
authors.forename: Céline
authors.initials: C
authors.lastname: Brochier-Armanet
authors.affiliation: International Center for Infectiology Research (CIRI), International Center for Infectiology Research, Université de Lyon, 69364 Lyon, France; INSERM U1111, 69364 Lyon, France; Ecole Normale Supérieure de Lyon, 69364 Lyon, France; Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, 69364 Lyon, France; CNRS UMR5308, 69007 Lyon, France;
authors.forename: Omran
authors.initials: O
authors.lastname: Allatif
authors.affiliation: CNRS UMR5240, Microbiologie Adaptation et Pathogénie, 69622 Villeurbanne, France; Université Claude Bernard Lyon 1, 69100 Villeurbanne, France;
authors.forename: Flora
authors.initials: F
authors.lastname: Peillard-Fiorente
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Edwards
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Ayat R
authors.initials: AR
authors.lastname: Omar
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: MacMillan
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Glover
authors.affiliation: CNRS UMR5240, Microbiologie Adaptation et Pathogénie, 69622 Villeurbanne, France; Université Claude Bernard Lyon 1, 69100 Villeurbanne, France; International Center for Infectiology Research (CIRI), International Center for Infectiology Research, Université de Lyon, 69364 Lyon, France; INSERM U1111, 69364 Lyon, France; Ecole Normale Supérieure de Lyon, 69364 Lyon, France; Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, 69364 Lyon, France; CNRS UMR5308, 69007 Lyon, France; xavier.charpentier@univ-lyon1.fr.
authors.forename: Xavier
authors.initials: X
authors.lastname: Charpentier
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D020869:Gene Expression Profiling / Q000379:methods; D015964:Gene Expression Regulation, Bacterial; D022761:Gene Transfer, Horizontal; D006801:Humans; D016952:Legionella pneumophila / Q000235:genetics* / Q000378:metabolism; D007877:Legionnaires' Disease / Q000382:microbiology; D008957:Models, Genetic; D012329:RNA, Bacterial / Q000235:genetics*; D018085:Regulon / Q000235:genetics; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial
keywords: Legionella pneumophila; ProQ/FinO; RNA chaperone; natural transformation; non-coding RNA