Research Highlights

Gene deletion improves protein expression system

Published online 13 February 2013

Ahmed Arafa

Baculoviruses, a family of rod-shaped viruses have proved a very handy tool for scientists. They can be used to infect insect cells, insert genes into the insect genome and prompt the cell to synthesize the gene into protein. Indeed, baculovirus expression systems are one of the most efficient ways to produce genetically engineered proteins. But even baculoviruses have their limits: they don't make cell membrane proteins very well, one of the most important targets in drug treatment.

Researchers from Michigan State University, Michigan, USA led by Suzanne Thiem, and Tamer Salem of Zewail University and the Agricultural Research Centre in Giza, Egypt, have identified that the deletion of the gene ORF34 improves protein expression in the Autographa californica baculovirus expression system1.

After the removal of the gene, the virus lost its ability to spread and infect other cells indicated by the absence of viruses budding from the membrane of infected cells. The authors suggest that the protein ORF34, which is part of a transcriptional unit including putative histidinol-phosphatase (ORF33) and fibroblast growth factor (ORF32), plays a role in the virulence of viruses, the packaging of the viral particle outside the host cell, trafficking from nucleus to the plasma membrane or in budding.

Further work is expected to understand the specific function of the ORF34 gene in the baculovirus lifecycle and how reducing its expression increases the expression of heterologous proteins.


  1. Salem, T. Z., Zhang, F. & Thiem, S. M. Reduced expression of Autographa californica nucleopolyhedrovirus ORF34, an essential gene, enhances heterologous gene expression. Virology 435(2), 225-238 (2013)