Functional characterization of heterologously expressed Plasmodium falciparum ebl proteins

Abstract

While heterologous expression has replaced biochemical purification as the principle method for obtaining purified, authentic proteins for characterization, no single expression system has proven appropriate for all applications. Heterologous expression of Plasmodium falciparum genes has proven especially challenging due to their extreme A+T codon bias and inappropriate post-translational modifications to product made by existing expression systems. These issues have generated interest in developing a novel heterologous expression system for P. falciparum. Here, we have transfected the ciliate Tetrahymena thermophila with a novel secretion vector bearing the R2 binding region of the P. falciparum genes, ebl-1 and jsebl. In addition, we demonstrated successful expression of the R2 region. This is the first demonstration of secreted P. falciparum antigens expressed by T. thermophila. We believe T. thermophila shows promise as a heterologous expression system for P. falciparum genes.