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Target evaluation of the non‐coding csRNAs reveals a link of the two‐component regulatory system CiaRH to competence control in S treptococcus pneumoniae R 6
Author(s) -
Schnorpfeil Anke,
Kranz Miriam,
Kovács Martá,
Kirsch Christian,
Gartmann Julia,
Brunner Ines,
Bittmann Sabrina,
Brückner Reinhold
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12277
Subject(s) - biology , microbiology and biotechnology , competence (human resources) , computational biology , psychology , social psychology
Summary The two‐component regulatory system CiaRH of S treptococcus pneumoniae controls 25 genes, five of which specify homologous small non‐coding csRNAs ( c ia‐dependent s mall 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 R 6, but their activity is only apparent in the absence of the protease gene htrA , another CiaRH regulon member.