Heterologous protein production in Acremonium chrysogenum: expression of bacterial cephalosporin C acylase and human thrombomodulin genes.

Abstract

We have developed an efficient expression system for foreign genes in Acremonium chrysogenum. After inserting the foreign gene between the phosphoglycerate kinase (PGK) promoter and a terminator derived from A. chrysogenum, multiple copies of this expression unit are tandemly ligated into cosmids and the resultant cosmids are introduced into A. chrysogenum. We expressed Pseudomonas cephalosporin C acylase and a human thrombomodulin mutant protein containing the fourth, fifth, and sixth epidermal growth factor (EGF)-like structures (E456). The acylase activity in the transformants obtained using our system was several times higher than that in the transformants without the use of the system. The acylase proteins expressed had enzymatic and immunochemical properties identical to those of authentic acylase. The transformants with the expression plasmid for E456 secreted biologically active E456 protein into the culture medium. The amino terminal sequence of the purified E456 was identical to that of recombinant E456 obtained using mammalian cells.