IMPROVEMENT OF PROMOTER ACTIVITY BY THE INTRODUCTION OF MULTIPLE COPIES OF THE CONSERVED REGION-III SEQUENCE, INVOLVED IN THE EFFICIENT EXPRESSION OF ASPERGILLUS-ORYZAE AMYLOSE-ENCODING GENES

The role of the conserved sequence region III in the promoter regions of the amylase-encoding genes amyB, glaA and agdA of Aspergillus oryza e was examined. Introduction of multiple copies of the region III frag ment into the agdA promoter resulted in a significant increase in prom oter activity at the transcriptional level. This result suggests that the fragment comprising region III consists of one or more cis-acting sequence(s). Moreover, expression of the agdA gene under the control o f the improved agdA promoter resulted in efficient overproduction of c l-glucosidase, even in the presence of glucose. Thus, overexpression o f genes controlled by the improved promoter incorporating region III i s possible. Interestingly, expression of the amyB and glaA genes in th e transformant was strongly repressed. This result suggests that the t r ans-acting regulatory protein(s) that interact with region III are c ommon to these amylase genes and that the titration of regulatory prot ein(s) reduced the expression of the amyB and glaA genes.