Bac-to-Bac baculovirus expression is an efficient method for producing baculovirus for high-level protein expression in insect cells. It relies on generation of recombinant virus by site-specific transposition in E. coli rather than homologous recombination in insect cells. The pFastBac HBM TOPO expression system features:

• Expression of secreted proteins—The Bac-to-Bac HBM TOPO vector contains the honeybee melittin (HBM) secretion signal to enable secreted protein expression. Because glycoproteins cannot be glycosylated in the absence of a secretion signal, this vector is recommended for the expression of glycoproteins.

• Flexibility—The Bac-to-Bac HBM TOPO vector contains a C-terminal His-tag with a TEV cleavage site to enable easy purification of His-tagged proteins with nickel-chelating resins (such as the Invitrogen ProBond Purification System) and generation of native proteins with the aid of the Invitrogen AcTEV Protease.

• Fast cloning, easy screening—Blunt TOPO cloning technology enables cloning of blunt-end PCR products into the pFastBac TOPO vector in five minutes. In addition, the pFastBac TOPO expression kit is supplied with Mach1-T1R E. coli that enable the visualization of colonies eight hours after plating on ampicillin-selective plates due to their faster doubling time compared to other standard cloning strains. Find out more about the advantages of TOPO cloning ›

• High transfection efficiency with ExpiFectamine Sf Transfection Reagent—The Bac-to-Bac TOPO expression kits now come with the next-generation ExpiFectamine Sf Transfection Reagent for efficient DNA transfection in insect cells using fast, flexible protocols. Find out more about this reagent ›

• Time-saving expression bacmid—With the Bac-to-Bac system, the expression cassette of the pFastBac vector recombines with the parent bacmid in DH10Bac E. coli Competent Cells to form an expression bacmid. The bacmid is then transfected into insect cells for production of recombinant baculovirus particles.

• Easy colony screening—The parent bacmid in DH10Bac E. coli contains a segment of the lacZa gene. The lacZa gene is disrupted upon transposition of the expression cassette into the bacmid, allowing for blue/white selection of recombinants for easier identification of recombinant colonies.

• High protein expression—The pFastBac vector uses the strong polyhedrin promoter to generate high levels of expression in a variety of insect cell line such as Sf9, Sf21, and High Five cells.