CDNA CLONING OF A TRICHODERMA-REESEI CELLULASE AND DEMONSTRATION OFF ENDOGLUCANASE ACTIVITY EXPRESSION IN YEAST

A Trichoderma reesei cDNA encoding a previously unknown protein with a C-terminal cellulose-binding domain was obtained by complementation s creening of a T. reesei cDNA library in a sec1 yeast mutant impaired i n protein secretion, The I: reesei protein shows amino acid similarity over its entire length to the Agaricus bisporus cellulose-induced pro tein CEL1 whose function is not known. These two proteins form ii new glycosyl hydrolase family, number 61. Expression of the T. reesei cDNA in yeast showed that it encoded ii protein with endoglucanase activit y and thus the protein was named EGIV and the corresponding gene egl4. Polyclonal antibodies were prepared against EGIV produced in Escheric hia coli and detected a 56-kDa protein in the T. reesei culture supern atant. Northern hybridisation revealed that T. reesei egl4 is regulate d in the same manner as other cellulase genes of this fungus.