Deletion Analysis of the Taka-amylase A Gene Promoter Using a Homologous Transformation System in Aspergillus oryzae

The Taka-amylase A gene (amyB) of Aspergillus oryzae is induced by starch or maltose. The molecular mechanism of the induction was investigated using a fusion of the amyB promoter and the Escherichia coli uidA gene encoding β-glucuronidase (GUS). To identify the region responsible for high-level expression and regulation within the amyB promoter, a series of deletion promoters was constructed and introduced into the A. oryzae met locus by homologous recombination. Deletion of the region between − 377 to − 290 (the number indicates the distance in base pairs from the translation initiation point (+ 1) to the deletion end point) significantly reduced of the GUS activity, but slight reduction of the GUS activity was observed in deletions up to − 377. Northern blot analysis showed that reduction of the GUS activity depended upon the expression level of the GUS gene. The region between − 377 to − 290 is suggested to include the sequence required directly for high-level expression and regulation of the amyB gene.