Value Proposition: A major limitation to efficient production of proteins in yeast has been vector systems that consistently yield large amounts of recombinant protein. Whereas yields of 20-50% of total protein can readily be attained in bacterial systems, yeast systems typically yield 1-2%, and only occasionally as high as 5%. Yet yeast is highly desirable as an expression system because as a unicellular eukaryote, it enjoys protein modification systems similar to those of human cells yet can be fermented in huge volumes at very low expense. This technology provides an improved 2µ plasmid expression system in S. cerevisiae that has high stability and high copy number in yeast. Other advantages include:
• Easy to use without the requirement for subcloning
• Vector is always competing with native 2µ for copy number in the yeast cell
• Copy number drivers can help increase copy number further
Technical Details: Johns Hopkins researchers have created a unique vector capable of maintaining stable high copy number in S. cerevisiae. These vectors contain the entire 2µ plasmid, and the vector sequences are inserted at a single nonessential site that does not disrupt any of the 2µ plasmid genes. These vectors exploit the copy number amplification system of native 2µ plasmids that requires 2 FLP recombination target (FRT) sites and the interconverting recombinase FLP. Because they possess this system, novel vectors amplify efficiently. A single plasmid copy can give rise to multiple copies even though the origin of replication fires once and only once per cell cycle.
Looking for Partners: To develop and commercialize the technology as a yeast expression system for recombinant protein production.
