Secretion of Escherichia coli β-galactosidase in Saccharomyces cerevisiae using the signal sequence from the glucoamylase-encoding STA2 gene

Abstract

The budding yeast Saccharomyces cerevisiae is a safe and widely used host for the production of recombinant DNA-derived proteins. We have used the signal sequence from the S. diastaticus STA2 gene, encoding glucoamylase II, to secrete Escherichia coli β-galactosidase, encoded by the lacZ gene. In frame STA2 lacZ gene fusions have been constructed and expressed in S. cerevisiae under the control of either the STA2 or the galactose inducible GAL1–10 upstream promoters. Fairly high amounts of the enzyme (up to 76% of total activity, depending on the growth conditions) are secreted in the periplasmic space. Adding yeast extract and peptone to the growth medium results in a dramatic increase in both synthesis and secretion of β-galactosidase.