The Optimization of Saccharomyces cerevisiae Expression System by Mutagenesis of Promoter and Host Strain

Abstract

An expression system with high efficiency is very important for recombinant proteins production in biopharmaceutical field. Saccharomyces cerevisiae is a food-graded eukayotic organism. The features of short generation time,simple culture condition and well-characterized manipulation techniques make yeast S. cerevisiae an attractive cell factory for production of heterologous protein. Here,for the purpose to improve the efficiency of p HR expression system which was constructed in our lab previously.,the promoter of p HR expression vector( PTEF) and host strain Y16 were modified by the way of error-prone PCR and mutagenesis respectively. After several rounds of screening,a mutant PTEFv1 with higher efficiency than the mother promoter PTEFwas obtained.Two modified yeast strains Y16-E14 and Y16-E19 were identified with higher productivity of heterologous protein than yeast Y16. Then PTEFv1 and yeast Y16-E14 were used to construct the novel p HR-N expression system. To evaluate the ability of p HR-N expression system,yeast green fluorescent protein( GFP) and human serum albumin( HSA) were chosed to be expressed intracellularly and extracellularly respectively. The results showed that p HR-N system had higher ability to produce either intracellular GFP or extracellular HSA than p HR system.The p HR-N yeast expression system provides a valuable resource for future application in recombinant protein production.