title: The Ustilago maydis nar1 gene encoding nitrate reductase activity: sequence and transcriptional regulation.
abstract: The nar1 gene was cloned from Ustilago maydis and the 908-amino-acid (aa) sequence of the encoded protein found to have strong identities with other nitrate reductases from fungi and plants. This was especially so in three domains which define enzyme cofactor-binding sites. The gene was isolated alone and in association with the nir1 gene, suggesting that the two genes are closely linked on the chromosome. The phenotype of a strain in which nar1 had been disrupted was consistent with the only role of nar1 being in nitrate reduction. Nitrate ions induced a 90-fold increase in nar1 transcript levels, while ammonium ions repressed transcript levels.
authors.affiliation: Genetics Division, National Institute for Medical Research, Mill Hill, London, UK.
authors.forename: G R
authors.initials: GR
authors.lastname: Banks
authors.forename: P A
authors.initials: PA
authors.lastname: Shelton
authors.forename: N
authors.initials: N
authors.lastname: Kanuga
authors.forename: D W
authors.initials: DW
authors.lastname: Holden
authors.forename: A
authors.initials: A
authors.lastname: Spanos
mesh_terms: D000595:Amino Acid Sequence; D001051:Apoenzymes / Q000235:genetics; D001483:Base Sequence; D015825:Chromosomes, Fungal; D003360:Cosmids; D004271:DNA, Fungal / Q000032:analysis; D005656:Fungal Proteins / Q000737:chemistry; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000737:chemistry* / Q000235:genetics*; D009572:Nitrite Reductases / Q000737:chemistry / Q000235:genetics*; D016366:Open Reading Frames; D014157:Transcription Factors; D014158:Transcription, Genetic; D015854:Up-Regulation; D014588:Ustilago / Q000201:enzymology* / Q000235:genetics*
chemical_list: D001051:Apoenzymes; D004271:DNA, Fungal; D005656:Fungal Proteins; D014157:Transcription Factors; D009565:Nitrate Reductases; D009572:Nitrite Reductases; D050901:Nitrate Reductase