title: The Streptococcus pneumoniae cia regulon: CiaR target sites and transcription profile analysis.
abstract: The ciaR-ciaH system is one of 13 two-component signal-transducing systems of the human pathogen Streptococcus pneumoniae. Mutations in the histidine protein kinase CiaH confer increased resistance to beta-lactam antibiotics and interfere with the development of genetic competence. In order to identify the genes controlled by the cia system, the cia regulon, DNA fragments targeted by the response regulator CiaR were isolated from restricted chromosomal DNA using the solid-phase DNA binding assay and analyzed by hybridization to an oligonucleotide microarray representing the S. pneumoniae genome. A set of 18 chromosomal regions containing 26 CiaR target sites were detected and proposed to represent the minimal cia regulon. The putative CiaR target loci included genes important for the synthesis and modification of cell wall polymers, peptide pheromone and bacteriocin production, and the htrA-spo0J region. In addition, the transcription profile of cia loss-of-function mutants and those with an apparent activated cia system representing the off and on states of the regulatory system were analyzed. The transcript analysis confirmed the cia-dependent expression of seven putative target loci and revealed three additional cia-regulated loci. Five putative target regions were silent under all conditions, and for the remaining three regions, no cia-dependent expression could be detected. Furthermore, the competence regulon, including the comCDE operon required for induction of competence, was completely repressed by the cia system.
authors.affiliation: Department of Microbiology, University of Kaiserslautern, Paul Ehrlich Strasse 23, D-67663 Kaiserslautern, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Mascher
authors.forename: Dorothea
authors.initials: D
authors.lastname: Zähner
authors.forename: Michelle
authors.initials: M
authors.lastname: Merai
authors.forename: Nadège
authors.initials: N
authors.lastname: Balmelle
authors.forename: Antoine B
authors.initials: AB
authors.lastname: de Saizieu
authors.forename: Regine
authors.initials: R
authors.lastname: Hakenbeck
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D000071677:Histidine Kinase; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D018085:Regulon; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; C088910:CiaR protein, Streptococcus pneumoniae