ENHANCEMENT OF RECOMBINANT GLUCOAMYLASE EXPRESSION BY INTRODUCING YEAST GAL7 MESSENGER-RNA TERMINATION SEQUENCE

Glucoamylase gene (STA1) of Saccharomyces diastaticus was expressed in recombinant Saccharomyces cerevisiae systems. The yeast, GAL7 mRNA te rmination sequence was introduced in the 3' noncoding region of the ST A1 structural gene which was under the control of the SUC2 promoter an d STA1 secretion signal sequence. This plasmid was named YEpSSG7 and w as introduced into yeast S. cerevisiae MMY2 to construct recombinant S . cerevisiae MMY2SSG7. The GAL7 mRNA termination sequence enhanced the glucoamylase expression level by 3-5 times depending on the culture c onditions compared to the result from the strain S. cerevisiae MMY2SUC STA which did not contain the GAL7 mRNA termination sequence. Such an enhancement was not due to plasmid stability or plasmid copy number ef fects. Such an enhancement was primarily due to the fact that GAL7 mRN A termination sequence stabilized the STA1 mRNA 3' end. (C) 1997 Elsev ier Science B.V.