title: Identification of competence pheromone responsive genes in Streptococcus pneumoniae by use of DNA microarrays.
abstract: Natural genetic transformation in Streptococcus pneumoniae is controlled in part by a quorum-sensing system mediated by a peptide pheromone called competence-stimulating peptide (CSP), which acts to coordinate transient activation of genes required for competence. To characterize the transcriptional response and regulatory events occurring when cells are exposed to competence pheromone, we constructed DNA microarrays and analysed the temporal expression profiles of 1817 among the 2129 unique predicted open reading frames present in the S. pneumoniae TIGR4 genome (84%). After CSP stimulation, responsive genes exhibited four temporally distinct expression profiles: early, late and delayed gene induction, and gene repression. At least eight early genes participate in competence regulation including comX, which encodes an alternative sigma factor. Late genes were dependent on ComX for CSP-induced expression, many playing important roles in transformation. Genes in the delayed class (third temporal wave) appear to be stress related. Genes repressed during the CSP response include ribosomal protein loci and other genes involved in protein synthesis. This study increased the number of identified CSP-responsive genes from approximately 40 to 188. Given the relatively large number of induced genes (6% of the genome), it was of interest to determine which genes provide functions essential to transformation. Many of the induced loci were subjected to gene disruption mutagenesis, allowing us to establish that among 124 CSP-inducible genes, 67 were individually dispensable for transformation, whereas 23 were required for transformation.
authors.affiliation: The Pathogen Functional Genomics Resource Center, The Institute for Genomic Research, Rockville, MD 20850, USA.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Peterson
authors.forename: Chang Kyoo
authors.initials: CK
authors.lastname: Sung
authors.forename: Robin
authors.initials: R
authors.lastname: Cline
authors.forename: Bhushan V
authors.initials: BV
authors.lastname: Desai
authors.forename: Erik C
authors.initials: EC
authors.lastname: Snesrud
authors.forename: Ping
authors.initials: P
authors.lastname: Luo
authors.forename: Jennifer
authors.initials: J
authors.lastname: Walling
authors.forename: Haiying
authors.initials: H
authors.lastname: Li
authors.forename: Michelle
authors.initials: M
authors.lastname: Mintz
authors.forename: Getahun
authors.initials: G
authors.lastname: Tsegaye
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Burr
authors.forename: Yu
authors.initials: Y
authors.lastname: Do
authors.forename: Susie
authors.initials: S
authors.lastname: Ahn
authors.forename: Joseph
authors.initials: J
authors.lastname: Gilbert
authors.forename: Robert D
authors.initials: RD
authors.lastname: Fleischmann
authors.forename: Donald A
authors.initials: DA
authors.lastname: Morrison
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000494:pharmacology / Q000502:physiology*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D010452:Peptide Biosynthesis / Q000235:genetics / Q000502:physiology; D010675:Pheromones / Q000494:pharmacology / Q000502:physiology; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics / Q000502:physiology; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000502:physiology*; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015533:Transcriptional Activation; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; C061262:ComA protein, Bacteria; C120829:ComX protein, Streptococcus; D004268:DNA-Binding Proteins; D010675:Pheromones; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012269:Ribosomal Proteins; D014157:Transcription Factors