title: Expression of the iron-responsive irpA gene from the cyanobacterium Synechococcus sp strain PCC 7942.
abstract: Expression of the iron-stress-induced irpA gene of Synechococcus sp. strain PCC 7942 was investigated by constructing luminescent p irpA::luxAB promoter fusions. Growth of Fe-replete and Fe-limited cultures yielded high levels of luminescence only under conditions of iron deficiency. Promoter fusion deletions revealed that low Fe irpA transcription is dependent on a 25-nucleotide sequence that includes a region of dyad symmetry centered 19 nucleotides from the transcription start. Assaying luminescence at defined iron concentrations in trace-metal-buffered media showed that irpA transcription is activated at concentrations below 100 nm Fe. Overall, the expression pattern and promoter structure of irpAsuggests a novel form of metal-dependent regulation in this species.
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH 43403, USA.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Durham
authors.forename: David
authors.initials: D
authors.lastname: Porta
authors.forename: R Michael L
authors.initials: RM
authors.lastname: McKay
authors.forename: George S
authors.initials: GS
authors.lastname: Bullerjahn
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D003470:Culture Media; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D033862:Iron-Binding Proteins; D008163:Luminescent Measurements; D008969:Molecular Sequence Data; D009154:Mutation; D033902:Periplasmic Binding Proteins; D011401:Promoter Regions, Genetic
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D003470:Culture Media; D033862:Iron-Binding Proteins; D033902:Periplasmic Binding Proteins