title: Analysis of a non-canonical NtcA-dependent promoter in Synechococcus elongatus and its regulation by NtcA and PII.
abstract: In this communication, we present a genetic analysis of the glnN promoter region of Synechococcus elongatus PCC 7942. luxAB reporter fusions were used to characterize the glnN promoter by deletion and site-directed mutational analysis. Reporter gene expression analysis was performed in S. elongatus wild-type and mutant strains to reveal the role of the global nitrogen responsive transcription factor NtcA and of the P(II) signalling protein on regulation of glnN gene expression. A non-canonical NtcA-binding motif is responsible for NtcA-dependent, nitrogen-responsive regulation of glnN. The P(II) signalling protein has opposing effects on NtcA-dependent glnN expression. Under conditions of nitrate-growth, it depresses expression, whereas under conditions of combined nitrogen starvation, it is required for full induction. Furthermore, sequences upstream of the NtcA-binding site have repressive effect on glnN promoter activity.
authors.affiliation: Institut für Mikrobiologie und Molekularbiologie der Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
authors.forename: M Fadi
authors.initials: MF
authors.lastname: Aldehni
authors.forename: Karl
authors.initials: K
authors.lastname: Forchhammer
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005974:Glutamate-Ammonia Ligase / Q000235:genetics; D051922:PII Nitrogen Regulatory Proteins / Q000502:physiology*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D050436:Regulatory Elements, Transcriptional; D015398:Signal Transduction; D046940:Synechococcus / Q000737:chemistry / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D051922:PII Nitrogen Regulatory Proteins; D014157:Transcription Factors; C075617:ntcA protein, Synechococcus; C404143:PIID regulatory protein, Bacteria; D005974:Glutamate-Ammonia Ligase