title: An iron stress operon involved in photosynthetic electron transport in the marine cyanobacterium Synechococcus sp. PCC 7002.
abstract: The iron-stress-induced genes isiA and isiB have been cloned and sequenced from the marine unicellular cyanobacterium Synechococcus sp. PCC 7002. These genes code for a photosystem II chlorophyll-binding protein and flavodoxin respectively. The genes form a dicistronic operon that is transcriptionally activated under iron-stress conditions to produce an abundant monocistronic message containing isiA and a much less abundant dicistronic message that also contains isiB. The arrangement of these genes, their transcriptional control and the relative abundance of the monocistronic and dicistronic messages produced under iron stress parallels the pattern shown by the freshwater cyanobacterium Synechococcus sp. PCC 7942. The genes for the corresponding proteins found under iron-replete conditions, CP-43 and ferredoxin, have also been cloned and sequenced. Northern blot analysis indicates that both of these genes are constitutively expressed under both iron-stress and iron-replete conditions.
authors.affiliation: Department of Botany, University of Toronto, Ontario, Canada.
authors.forename: K
authors.initials: K
authors.lastname: Leonhardt
authors.forename: N A
authors.initials: NA
authors.lastname: Straus
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics* / Q000378:metabolism; D004247:DNA; D004579:Electron Transport; D005288:Ferredoxins / Q000235:genetics*; D005418:Flavodoxin / Q000235:genetics*; D005786:Gene Expression Regulation; D007501:Iron / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009876:Operon; D010788:Photosynthesis / Q000235:genetics*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D045332:Photosystem II Protein Complex; D015183:Restriction Mapping; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D005288:Ferredoxins; D005418:Flavodoxin; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C076726:chlorophyll A binding protein CP43, Cyanobacteria; D004247:DNA; D007501:Iron