Integration host factor affects the oxygen-regulated expression of photosynthesis genes in Rhodobacter capsulatus.
The puf and puc operons of Rhodobacter capsulatus, which encode pigment binding proteins, are regulated by oxygen tension. Strain IR4 which carries a point mutation in the himA gene for integration host factor (IHF) shows a delayed increase in the amount of photosynthetic complexes after reduction of oxygen tension when compared to the isogenic wild-type strain. This delay in the formation of photosynthetic complexes correlates with a delay in increasing the level of transcription of the puf and puc operons, whereas the transcription of the bchD genes is not affected by IHF. Several IHF binding sites can be identified upstream of the puf and puc transcriptional starts by in vitro footprint analysis. Our results suggest that IHF facilitates the binding of other trans-acting factors, e.g. RegA, which in turn stimulate transcription of the puf and puc genes under low oxygen tension.
Kirndörfer
M
M
Institut für Mikrobiologie und Molecularbiologie, Universität Giessen, Germany.
Jäger
A
A
Klug
G
G
D001426:Bacterial Proteins / Q000235:genetics*; D001429:Bacteriochlorophylls / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000032:analysis; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics; D034982:Integration Host Factors; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon / Q000235:genetics; D010100:Oxygen / Q000494:pharmacology*; D010788:Photosynthesis / Q000235:genetics*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D016354:Rhodobacter capsulatus / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics
D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D004268:DNA-Binding Proteins; D034982:Integration Host Factors; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D012333:RNA, Messenger; C440504:integration host factor, Rhodobacter; D010100:Oxygen