title: Target evaluation of the non-coding csRNAs reveals a link of the two-component regulatory system CiaRH to competence control in Streptococcus pneumoniae R6.
abstract: The two-component regulatory system CiaRH of Streptococcus pneumoniae controls 25 genes, five of which specify homologous small non-coding csRNAs (cia-dependent small RNAs). The csRNAs were predicted to act regulatory as base-pairing sRNAs, but their targets have not been identified. By csRNA gene inactivations we established that the major phenotypes associated with a hyperactive CiaRH system, enhanced β-lactam resistance and prevention of genetic competence, are dependent on the csRNAs. Computational target predictions and evaluations by translational fusions identified six genes to be under csRNA control: spr0081, spr0371, spr0159, spr0551, spr1097 and spr2043(comC). Measuring the effect of single csRNAs on three targets indicated that they acted additively. One of the targets, comC(spr2043), encoding the precursor of the competence stimulating pheromone CSP, constitutes a link of CiaRH to competence control. Partially disrupting predicted csRNA-comC complementarity led to strongly diminished repression by the csRNAs and to transformability in a strain with a hyperactive CiaRH. Thus, a hyperactive CiaRH system prevents competence development by csRNA-dependent post-transcriptional repression of CSP production. The csRNAs are also involved in competence regulation in the wild-type strain R6, but their activity is only apparent in the absence of the protease gene htrA, another CiaRH regulon member.
authors.affiliation: Department of Microbiology, University of Kaiserslautern, D-67663, Kaiserslautern, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Schnorpfeil
authors.forename: Miriam
authors.initials: M
authors.lastname: Kranz
authors.forename: Martá
authors.initials: M
authors.lastname: Kovács
authors.forename: Christian
authors.initials: C
authors.lastname: Kirsch
authors.forename: Julia
authors.initials: J
authors.lastname: Gartmann
authors.forename: Ines
authors.initials: I
authors.lastname: Brunner
authors.forename: Sabrina
authors.initials: S
authors.lastname: Bittmann
authors.forename: Reinhold
authors.initials: R
authors.lastname: Brückner
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018390:Gene Targeting; D011401:Promoter Regions, Genetic; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D058727:RNA, Small Untranslated / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018085:Regulon; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D018440:beta-Lactam Resistance / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D058727:RNA, Small Untranslated; C423628:competence factor, Streptococcus; D011494:Protein Kinases; C088910:CiaR protein, Streptococcus pneumoniae