RECENT ADVANCES IN THE EXPRESSION OF FOREIGN GENES IN PICHIA-PASTORIS

The Pichia pastoris heterologous gene expression system has been utili zed to produce attractive levels of a variety of intracellular and ext racellular proteins of interest. Recent advances in our understanding and application of the system have improved its utility even further. These advances include: (1) methods for the construction of P. pastori s strains with multiple copies of AOX1-promoter-driven expression cass ettes; (2) mixed-feed culture strategies for high foreign protein volu metric productivity rates; (3) methods to reduce proteolysis of some p roducts in high cell-density culture media; (4) tested procedures for purification of secreted products; and (5) detailed information on the structures of N-linked oligosaccharides on P pastoris secreted protei ns. In this review, these advances along with basic features of the P. pastoris system are described and discussed.