Expression of Bombyx mori cytoplasmic polyhedrosis virus polyhedrin in insect cells by using a baculovirus expression vector, and its assembly into polyhedra

1 Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Kyoto 606 and 2 National Institute of Agrobiological Resources, Tsukuba 305, Japan A cDNA encoding the cytoplasmic polyhedrin of Bombyx mori cytoplasmic polyhedrosis virus ( Bm CPV) strain H was introduced into an improved baculovirus expression vector which can be utilized to express foreign genes in the Spodoptera frugiperda cell line IPLB-SF-21AE (Sf21 cells) and the B. mori cell line BmN. A recombinant virus produced large, cubic inclusion body-like structures in infected Sf21 and BmN cells. Western blot analysis showed that these structures were Bm CPV polyhedra. This result suggested that the supramolecular assembly of Bm CPV polyhedrin is responsible for its properties. Received 17 June 1992; accepted 21 September 1992.