GENETIC AND MOLECULAR CHARACTERIZATION OF PURINE PERMEASE GENES OF ASPERGILLUS-NIDULANS REVEALS A NOVEL FAMILY OF TRANSPORTERS CONSERVED INPROKARYOTES AND EUKARYOTES

The ascomycete fungus Aspergillus nidulans can utilize purines (adenin e, guanine, hypoxanthine, xanthine, and uric acid) as sole nitrogen so urces [1]. The expression of most structural genes involved in the pat hway of purine uptake and catabolism is subject to uric acid induction , mediated by the product of the positive regulatory gene uaY, and to nitrogen metabolite repression, mediated by the product of the general , positive-acting, GATA-like transcription factor, encoded by the are4 gene [1].