ANALYSIS OF CRE1 BINDING-SITES IN THE TRICHODERMA-REESEI CBH1 UPSTREAM REGION

A 1.5-kb XbaI-SacII fragment containing the upstream region of the Tri choderma reesei cellobiohydrolase I gene (cbhl) has been sequenced. Th e 1.5-kb fragment contains eight 6-bp sites having an identical or sim ilar sequence to the consensus sequence for binding a catabolite repre ssor, Aspergillus nidulans CreA. Results of binding assays with the ma ltose-binding protein::Cre1(10-131) fusion protein (Cre1 is a cataboli te repressor of T. reesei) and the cbh1 upstream region revealed that a 504-bp XbaI-NspV fragment (nucleotide position -1496 to -993) bearin g three 6-bp sites, A1, A2, and A3, and a 356-bp NspV-MunI fragment (n ucleotide position -994 to -639) bearing three 6-bp sites, B1, B2, and B3, were shifted in the electrophoretic mobility shift assay. DNase I footprinting experiments showed that the 6-bp sites A2, B1, B2, and B 3 were protected from DNase I digestion.