title: Effects of PipX on NtcA-dependent promoters and characterization of the cox3 promoter region in the heterocyst-forming cyanobacterium Anabaena sp. PCC 7120.
abstract: In Anabaena, the pipX gene is induced in the cells differentiating into heterocysts, being the PipX factor required for full expression of late heterocyst-specific genes. Here we show that PipX has a positive effect on in vitro binding of the transcription factor NtcA to DNA, as well as on transcript production, in different NtcA-dependent promoters. We found that the cox3 operon, encoding a heterocyst-specific terminal respiratory oxidase, is expressed from three nitrogen-regulated promoters to which NtcA binds. At the three sites, NtcA binding is potentiated by PipX. Thus, PipX has a direct effect on gene expression influencing the activity of NtcA.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
authors.forename: Sergio
authors.initials: S
authors.lastname: Camargo
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Valladares
authors.affiliation: Lehrstuhl für Mikrobiologie/Organismische Interaktionen, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Forchhammer
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain. Electronic address: herrero@ibvf.csic.es.
authors.forename: Antonia
authors.initials: A
authors.lastname: Herrero
mesh_terms: D017033:Anabaena / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D016384:Consensus Sequence; D018983:DNA Footprinting; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014157:Transcription Factors; D003576:Electron Transport Complex IV
keywords: Cyanobacteria; Transcriptional regulation