The AzgA purine transporter of Aspergillus nidulans. Characterization of a protein belonging to a new phylogenetic cluster.
The azgA gene of Aspergillus nidulans encodes a hypoxanthine-adenine-guanine transporter. It has been cloned by a novel transposon methodology. The null phenotype of azgA was defined by a number of mutations, including a large deletion. In mycelia, the azgA gene is, like other genes of purine catabolism, induced by uric acid and repressed by ammonium. Its transcription depends on the pathway-specific UaY zinc binuclear cluster protein and the broad domain AreA GATA factor. AzgA is not closely related to any other characterized membrane protein, but many close homologues of unknown function are present in fungi, plants, and prokaryotes but not metazoa. Two of three data bases and the phylogeny presented in this article places proteins of this family in a cluster clearly separated (but perhaps phylogenetically related) from the NAT family that includes other eukaryotic and prokaryotic nucleobase transporters. Thus AzgA is the first characterized member of this family or subfamily of membrane proteins.
Unidad Asociada de Microbiología, Facultad de Ciencias, Universidad de la República, Casilla de Correos 1157, Montevideo, Uruguay.
Gianna
G
Cecchetto
Sotiris
S
Amillis
George
G
Diallinas
Claudio
C
Scazzocchio
Christine
C
Drevet
D000225:Adenine / Q000737:chemistry; D000483:Alleles; D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000737:chemistry / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D017353:Gene Deletion; D019271:Hypoxanthine / Q000737:chemistry / Q000493:pharmacokinetics; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000502:physiology; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D016296:Mutagenesis; D009154:Mutation; D009584:Nitrogen / Q000737:chemistry; D010641:Phenotype; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014158:Transcription, Genetic; D014466:Ultraviolet Rays; D014527:Uric Acid / Q000494:pharmacology
D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D000644:Quaternary Ammonium Compounds; D014527:Uric Acid; D019271:Hypoxanthine; D004247:DNA; D000225:Adenine; D009584:Nitrogen