FINE-STRUCTURE MAPPING OF THE ACETAMIDASE STRUCTURAL GENE AND ITS CONTROLLING REGION IN ASPERGILLUS NIDULANS

A large number of amdS mutants altered in acetamide utilization have been used to construct a fine-structure map of the amdS locus. The mutagen diepoxyoctane generated most of the deletion strains used for mapping. A minimum of 14 sites within the amdS gene were found. Biochemical analysis of amds mutants defined the extent of the probable coding region. A new mutant, amd-205, which did not produce detectable inactive gene product, was found to be inseparable by recombination from the "up-promoter" mutation amdl8 and was located outside of the apparent amdS coding region. The cis dominant mutation, amdI9, was also located at this end of the gene. This work, therefore, provides evidence for the separation of a eukaryotic gene into controlling and structural regions.