title: Expression of the narX, narL, narP, and narQ genes of Escherichia coli K-12: regulation of the regulators.
abstract: The products of four Escherichia coli genes (narX, narL, narQ, and narP) regulate anaerobic respiratory gene expression in response to nitrate and nitrite. We used lacZ gene and operon fusions to monitor the expression of these nar regulatory genes in response to different growth conditions. Maximal expression of the narXL operon required molybdate, nitrate, and integration host factor. Expression of the narP and narQ genes was weakly repressed by nitrate. The NarL and NarP proteins were required for full nitrate induction of narXL operon expression, whereas the nitrate repression of narP and narQ expression was mediated solely by the NarL protein. narXL operon expression was unaffected by anaerobiosis, whereas expression of narP and narQ was induced approximately fourfold. The Fnr and ArcA proteins were not required for this anaerobic induction.
authors.affiliation: Section of Microbiology, Cornell University, Ithaca, New York 14853-8101, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Darwin
authors.forename: V
authors.initials: V
authors.lastname: Stewart
mesh_terms: D000693:Anaerobiosis / Q000502:physiology; D001426:Bacterial Proteins / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008565:Membrane Proteins / Q000096:biosynthesis; D008982:Molybdenum / Q000494:pharmacology; D009566:Nitrates / Q000494:pharmacology; D009573:Nitrites / Q000494:pharmacology; D010750:Phosphoproteins / Q000096:biosynthesis; D011494:Protein Kinases; D011993:Recombinant Fusion Proteins
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D009566:Nitrates; D009573:Nitrites; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C081466:narP protein, E coli; C088708:narQ protein, E coli; C069780:NarL protein, E coli; C044659:molybdate; D008982:Molybdenum; D011494:Protein Kinases; C074787:narX protein, E coli