Co-expression of human chaperone Hsp70 and Hsdj or Hsp40 co-factor increases solubility of overexpressed target proteins in insect cells

The insect-baculovirus expression system has proved particularly useful for producing recombinant proteins that are biologically active. Overexpressio n of foreign proteins using the recombinant baculovirus system is often acc ompanied by aggregation of the overexpressed protein, which is thought to b e due to a limitation of the translated protein folding in the infected cel ls. Co-infection of a recombinant baculovirus capable of expressing the hum an chaperone Hsp70 slightly increased the solubility of the overexpressed E pstein-Barr virus replication protein, BZLF1. Co-expression of Hsp70 and it s co-factor, Hsdj or Hsp40, was here found to improve the solubility of the target protein several fold. Thus, a baculovirus expression system produci ng these molecular chaperones may find application for improved production of target foreign gene products in insect cells. (C) 2000 Elsevier Science B.V. All rights reserved.