The Baculovirus Expression Vector System (BEVS) is a convenient and versatile eukaryotic system for heterologous gene expression. Baculovirus expression provides correct folding of recombinant protein as well as disulfide bond formation, oligomerization and other important post_x0002_translational modifications. Consequently, the overexpressed protein exhibits the proper biological activity and function. The Baculovirus Expression Vector System is based on the introduction of a foreign gene into a nonessential region of the viral genome via homologous recombination with a transfer vector containing the cloned gene; an event that occurs in the co-transfected insect cells. The production of foreign protein is achieved by infection of additional insect cell cultures with the resultant recombinant virus. The Baculovirus Expression Vector System from BD Biosciences Pharmingen employs a modified Autographa californica nuclear polyhedrosis virus (AcNPV) genome— BD BaculoGold? DNA, and an appropriate transfer vector. The diversity of AcNPV-based transfer vectors, combined with available S. frugiperda Sf9 and Sf21 cell lines, establish baculovirus expression as a preferred system for functional eukaryotic gene expression and the large-scale production of recombinant proteins. The baculovirus expression system offers the following advantages over prokaryotic and other eukaryotic systems: ? High Level of Protein Expression Yields of up to 100 mg of protein per 109 cells. ? Post-Translational Modifications Including disulfide bond formation, phosphorylation, glycosylation, oligomerization, and folding. ? Relevant Cellular Compartmentalization of Proteins Secreted, membrane-bound, cytoplasmic or nuclear. ? Capacity of Large cDNA Inserts Accommodates genes up to 8 kb. ? Simultaneous Expression of Multiple Genes With multiple promoter transfer vectors. I