A yeast system for stable expression of hepatitis B surface antigen

Area of Science:

• Biotechnology
• Molecular Biology
• Virology

Background:

• Hepatitis B virus (HBV) surface antigen (HBsAg) is a key component for vaccine development.
• Recombinant protein expression in yeast offers a cost-effective production platform.
• Efficient expression of foreign genes in Saccharomyces cerevisiae can be challenging.

Purpose of the Study:

• To develop a yeast strain for high-level expression of Hepatitis B virus surface antigen.
• To investigate methods for enhancing recombinant protein yield in yeast.

Main Methods:

• Constructed a Saccharomyces cerevisiae strain with integrated copies of the Hepatitis B virus surface antigen gene.
• Utilized the glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter and terminator for gene expression control.
• Applied chemical and physical mutagenesis followed by immunological screening to isolate high-expressing mutants.

Main Results:

• Initial yeast strain showed low-level expression of HBsAg.
• Mutagenesis and screening successfully identified a mutant clone with significantly high HBsAg protein expression.
• The high-expressing mutant strain demonstrated stable HBsAg production without selective pressure.

Conclusions:

• A stable, high-level producer yeast strain for Hepatitis B virus surface antigen has been successfully developed.
• This engineered strain represents a promising platform for cost-effective HBsAg production.
• The methodology employed can be applicable for enhancing expression of other recombinant proteins in yeast.