(724c) Expression Enhancing Introns for Increased Protein Expression In Yeast

In the field of metabolic engineering, strong overexpression of pathway genes is recognized as one of the principle strategies towards increasing flux of desired products. In model organisms such as E. coli and S. cerevisiae, there are a variety of well-characterized, strong-expression systems available. However, as other organisms become more relevant for industrial applications, there is a growing need for broadly applicable systems which can provide strong expression. Here we examine the use of expression-enhancing introns for strong gene overexpression. The spliceosomal intron sequence from the translation elongation factor (TEF) open reading frame produces a 15-fold increase in expression over the intron-less promoter sequence in the oleaginous yeast organism, Yarrowia lipolytica. We use this strong expression platform to increase the expression of endogenous diacylglycerol acyltransferase (DGA) to increase lipid accumulation in Y. lipolytica. Increased lipid accumulation can be used for the microbial production of triglycerides (TAG) and poly-unsaturated fatty acids (PUFAs) for biodiesel and nutraceutical applications. The strong expression-enhancement from introns demonstrates an effective platform for gene overexpression which utilizes endogenous machinery and is potentially applicable to a variety of yeast species. Furthermore it helps establish Y. lipolytica as an emergent organism for industrial applications in protein production and lipid accumulation.