[Expression of gene encoding HBsAg in yeast cell with its alpha-factor promoter]

Construction of an E. coli-yeast shuttle plasmid was reported with yeast alpha-factor as promoter of synthesis and secretion of mature foreign proteins by yeast cells (Saccharomyces cerevisiae). The HBsAg gene was successfully recombined into the plasmid with its frame precisely adjusted, thus resulting in extracellular secretion of HBsAg protein by the yeast cells.