Baculovirus ETL promoter acts as a shuttle promoter between insect cells and mammalian cells1

Abstract

To identify a shuttle promoter that can mediate gene expression in both insect cells and mammalian cells to facilitate the development of a baculovirus vector-based mammalian cell gene delivery vehicle. Recombinant baculoviruses carrying the beta-galactosidase reporter gene under the control of an early to late (ETL) promoter of the Autographa californica multiple nuclear polyhedrosis virus (AcMNPV) or a cytomegalovirus immediate early promoter (CMV promoter) were constructed. COS1, HeLa, CHO-K1, hFob1.19, and MCF-7 mammalian cells were tested for the expression of b-galactosidase. ETL promoter activity was higher in bone-derived hFob1.19 than in COS1, HeLa, CHO-K1, or MCF-7 mammalian cells. The transient plasmid transfection assay indicated that ETL promoter activity in mammalian cells was dependent on baculovirus gene expression. ETL promoter activity in mammalian cells is baculovirus gene expression-dependent, and the shuttle promoter will facilitate the application of baculovirus expression vectors in mammalian cell expression systems and for gene therapy.