A RECOMBINATION-EFFICIENT BACULOVIRUS VECTOR FOR SIMULTANEOUS EXPRESSION OF MULTIPLE GENES

The baculovirus system is an extremely powerful tool for expression of heterologous genes in eukaryotic environment. A multiple expression v ector, pBacUCmP3, was constructed which harbored two copies of the Aut ographa californica nuclear polyhedrosis virus very late gene promoter and the Drosophila melanogaster 70-kDa heat-shock protein (hsp70) pro moter with downstream unique restriction sites for cloning of three in dependent foreign genes. Co-transfection of pBacUCmP3 with Bsu36I-line arized viral DNA yields recombinant progeny viruses at very high frequ encies. The utility of this multiple expression transfer vector was de monstrated using three heterologous reporter genes encoding the beta-s ubunit of the human chorionic gonadotropin hormone, firefly luciferase and the bacterial beta-galactosidase (beta Gal) enzyme. The expressio n of reporter genes, monitored at various times post-infection, confir med that while beta-Gal synthesis was under the transcriptional contro l of the hsp70 promoter, the beta hCG and Luc proteins were synthesize d as a function of polyhedrin promoter activation profile. This vector will be useful for multiple synthesis of proteins at different time p oints.