The secretion and post translational modification of interferons from Saccharomyces cerevisiae.

Studies with three interferon molecules, IFN-alpha 2, IFN-beta 1, and a "hybrid" interferon, IFNX-430 are described which illustrate that both the expression and secretion characteristics of heterologous proteins in yeast cells reflect properties of the proteins themselves. Recombinant DNA techniques have also been used to demonstrate that the efficient processing of mature heterologous proteins from the yeast alpha factor secretion leader can be affected by sequences on the carboxyl side of the initial cleavage site. Secretion studies with heterologous proteins in S. cerevisiae are aimed at maximising yield, the percentage of extracellular product and correct amino terminus sequence. The results presented here show that all three factors are susceptible to currently unpredictable properties of the foreign sequence. This situation, in turn, means that heterologous proteins can be used as tools in the biochemical dissection of the yeast secretion process.