The veA gene is necessary for the inducible expression by fructosyl amines of the Aspergillus nidulans faoA gene encoding fructosyl amino acid oxidase (amadoriase, EC 1.5.3)

The faoA gene encoding fructosyl amino acid oxidase (FAOD, EC 1.5.3) was isolated from Aspergillus nidulans and characterized. The complete nucleotide sequence of the faoA (fructosyl amino acid oxidase) gene and its cDNA revealed that the faoA gene encodes a 441-amino-acid polypeptide interrupted by five introns. Expression of the A. nidulans faoA gene was inducible by fructosyl propylamine and fructosyl lysine, as is the case for the gene encoding FAOD in other organisms. The faoA gene was not induced by these fructosyl amines in a null mutant of the veA gene, which has been identified as an activator of sexual development and as an inhibitor of asexual development; the faoA gene was induced greatly in a veA(+) wild-type. However, veA gene expression was not affected by fructosyl amines. Even in the absence of fructosyl propylamine, synthesis of the faoA transcript was higher in the veA(+) background than in a veA-null mutation background. These results indicated that faoA gene expression is inducible by fructosyl amines and by the veA gene, and that the veA gene is necessary for full induction of faoA gene expression by fructosyl amines. Thus, the faoA gene is the first gene whose expression is dependent on the veA gene. Furthermore, the faoA gene, present in a single copy, seems to be dispensable for development and growth, since the faoA-null mutant grew normally and developed as many conidia and sexual structures as the wild-type.