EXPRESSION OF MOUSE ANTICREATINE KINASE-M (MAK 33), FAB FRAGMENT OF IgG ANTIBODY IN THE METHYLOTROPIC YEAST HANSENULA POLYMORPHA 1- Kappa Chain

Abstract

An expression plasmid was constructed and transformed to Hansenula polymorpha cells to produce kappa chain peptide of Fab fragment of the MAK33, IgG antibody. The yeast Hansenula polymorpha was shown to be one of the most efficient host cells for expression of genetically engineered antibody genes. Although the rate of transformation of this yeast by polyethylene glycol was low, 3-5 cells/plasmid DNA, yet the transformants showed high mitotic stability for more than 100 generations. The expression plasmid was integrated within the yeast genome in one or more integration site (s) with low and multicopy-number plasmid via non-homologous integration mechanism. A N-terminal glucoamylase gene fragment was linked to the light chain (kappa) gene of the Fab derivative of the MAK 33 antibody. Prepro-alpha factor of the yeast S. cerevisiae was inserted into the plasmid between Blucoamylase and light chain genes as a secretion signal sequence for the light chain peptide. The kappa chain was produced as 30 ngL free protein in the culture medium and 500 mg/L entrapped within the cells, amounting 550 mg/L, representing about 10% of the total cell protein. The prepro-factor was shown to be incompletely processed in the yeast Hansenula polymorpha and the pro-segment was accompanied with the light chain peptide.