crnA encodes a nitrate transporter in Aspergillus nidulans

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 88; no. 1; pp. 204 - 208
• Main Authors: Unkles, S.E. (University of St. Andrews, Fife, Scotland, UK), Hawker, K.L, Grieve, C, Campbell, E.I, Montague, P, Kinghorn, J.R
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.01.1991; National Acad Sciences
• Subjects: Amino Acid Sequence; amino acid sequences; Amino acids; Anion Transport Proteins; ASPERGILLUS NIDULANS; Aspergillus nidulans - genetics; Aspergillus nidulans - metabolism; Base Sequence; Biological and medical sciences; Carrier Proteins; Carrier Proteins - genetics; Cloning, Molecular; CODE GENETIQUE; CODIGO GENETICO; Complementary DNA; Complementary RNA; DNA, Fungal; DNA, Fungal - genetics; DNA, Fungal - isolation & purification; Escherichia coli; Escherichia coli - genetics; EXPRESION GENICA; EXPRESSION DES GENES; FENOTIPOS; Fundamental and applied biological sciences. Psychology; Fungal Proteins; Fungal Proteins - genetics; gene expression; Genes; Genes, Fungal; Genes. Genome; genetic code; GENETICA; GENETICA MOLECULAR; genetics; GENETIQUE; GENETIQUE MOLECULAIRE; isolation & purification; Messenger RNA; metabolism; Models, Structural; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; MUTANT; MUTANTES; mutants; Mutation; NITRATE; Nitrates; Nitrates - metabolism; NITRATOS; Nitrites; Nitrogen; NUCLEOTIDE; nucleotide sequences; Nucleotides; NUCLEOTIDOS; PHENOTYPE; Plasmids; Protein Conformation; PROTEINAS; PROTEINE; proteins; Quaternary ammonium compounds; Restriction Mapping; Sequence Homology, Nucleic Acid; Transcription, Genetic; Nucleotide sequence; Biological transport; Nitrates; Fungi; Northern blotting; Binding protein; Regulation(control); Gene; Aspergillus nidulans; Restriction map; Fungi Imperfecti; Computer aid; Thallophyta
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.88.1.204

The nucleotide sequence of the Aspergillus nidulans crnA gene for the transport of the anion nitrate has been determined. The crnA gene specifies a predicted polypeptide of 483 amino acids (molecular weight 51,769). A hydropathy plot suggests that this polypeptide has 10 membrane-spanning helices with an extensive hydrophilic region between helices six and seven. No striking homology was observed between the crnA protein and other reported membrane proteins of either prokaryotic or eukaryotic organisms, indicating that the crnA transporter may represent another class of membrane protein. Northern blotting results with wild-type cells show that (i) control of crnA expression is subject to nitrate (and nitrite) induction as well as nitrogen metabolite repression and (ii) regulation of the crnA gene is exerted at the level of mRNA accumulation, most likely at transcription, in response to the nitrogen source in the growth medium. Furthermore, similar studies with mutants of nirA and areA control genes and the niaD nitrate reductase structural gene show that crnA expression is mediated by the products of nirA (nitrate induction control gene), areA (nitrogen metabolite repression control gene), and niaD (involved in autoregulation of nitrate reductase)