Two separate quorum-sensing systems upregulate transcription of the same ABC transporter in Streptococcus pneumoniae.
Streptococcus pneumoniae secretes two different peptide pheromones used for intercellular communication. These peptides, which have completely unrelated primary structures, activate two separate signal transduction pathways, ComABCDE and BlpABCSRH, which regulate natural genetic transformation and bacteriocin production, respectively. Each signal transduction pathway contains a response regulator (ComE and BlpR, respectively) that activates transcription of target genes by binding to similar, but not identical, imperfect direct repeat motifs. In general the direct repeat binding sites are specific for one or the other of the two response regulators, ensuring that competence development and bacteriocin production are regulated separately. However, in the present study we show that the rate of transcription of an operon, encoding an ABC transporter of unknown function, can be stimulated by both peptide pheromones. We also show that this cross-induction is due to a hybrid direct repeat motif that can respond to both ComE and BlpR. To our knowledge this kind of convergent gene regulation by two separate two-component regulatory systems has not been described before in bacteria.
Knutsen
Eivind
E
Department of Chemistry, Biotechnology, and Food Science, Agricultural University of Norway, N-1432 As, Norway.
Ween
Ola
O
Håvarstein
Leiv Sigve
LS
D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009876:Operon; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D015854:Up-Regulation
D018528:ATP-Binding Cassette Transporters