Abstract
1 Departments of Entomology and Environmental Toxicology, University of California, Davis, California 95616
2 Boyce Thompson Institute for Plant Research at Cornell, Tower Road, Ithaca, New York 14853-1801, U.S.A.
3 Department of Virology, Agricultural University, Wageningen, P.O. Box 8045, 6700 EM Wageningen, The Netherlands
and4 NERC Institute of Virology and Environmental Microbiology, Mansfield Road, Oxford OX1 3SR, U.K.
The expression characteristics of the p10, polyhedrin and basic protein promoters of Autographa californica nuclear polyhedrosis virus were compared using two reporter enzymes, juvenile hormone esterase (JHE) and -galactosidase. In these systems, JHE is exported from the cell and -galactosidase is localized to the cytosol. Expression of JHE from the basic, p10 and polyhedrin promoters was first detected in the medium at 13, 19 and 27 h post-infection respectively. The basic protein promoter yielded the highest expression of the three promoters tested for both enzymes, as determined by protein and enzyme activity assays. In addition, yields of -galactosidase and JHE under control of the p10 promoter are higher relative to expression under control of the polyhedrin promoter. These data highlight the importance of investigation of viral promoters other than the polyhedrin promoter for high yield protein expression in vitro, and for insecticidal use of recombinant baculoviruses requiring high levels of expression. The results support revision of the current concept that very late viral promoters are always optimal for high yield recombinant protein expression.