Enhanced Recombinant Protein Expression in Insect Cells in the Presence of Dimethylsulfoxide (DMSO)

Abstract

The use of insect cells to express many recombinant homologous and heterologous proteins is reported throughout the scientific literature. A popular insect promoter is the metallothionein (Mtn) promoter which can be induced by the addition of heavy metals such as CuSO ₄ In this report we present data from Drosophila melanogaster Schneider 2 (S2) cells that have been stably transfected and express several different proteins under the control of the Mtn promoter. Selection was achieved using the hygromycin B-resistant gene derived from Escherichia coli. Our data show that such stably transfected insect cells expressing several different types of proteins, such as fusion proteins, soluble receptors and antigens, have enhanced product expression when the cells are treated with 1% dmethylsulfoxide (DMSO) prior to induction with CuSO ₄ When DMSO is added at least 12 hours before the addition of 750 uM CuSO ₄ protein expression increased 5 to 8-fold. The addition of DMSO at other times, was not as effective in stimulating expression. Furthermore, DMSO did not affect expression from the D. melanogaster constitutive actin promoter.