[Effect of 3'-UTR of EG I from Trichoderma reesei on its gene expression in Saccharomyces cerevisiae]

Several industrial yeast are developed as ideal expression hosts for the production of the commercially useful proteins. The expression levels in yeast cells of the heterologous proteins are affected by the regulation factors of the genes themselves. The full-length cDNA coding for EG I from Trichoderma reesei, the cellulose-degrading filamentous fungus, was expressed in Saccharomyces cerevisiae H158. EG I produced by the recombinant S. cerevisiae exhibits maximal activity at 50 degrees C-60 degrees C, pH 5.0. It was observed that removal of the 3'-untranslated region (3'-UTR) from EG I cDNA resulted in no active EG I produced by recombinant yeast. RT-PCR analysis indicated that unlike the yeast cells harboring full-length EG I cDNA, there was no detectable EG I mRNA in the yeast cells harboring EG I cDNA without 3'-UTR. The data suggested that 3'-UTR is important for the expression of EG I in Saccharomyces cerevisiae.