Enhanced and prolonged baculovirus-mediated expression by incorporating recombinase system and in cis elements: a comparative study.

Baculovirus (BV) is a promising gene vector but mediates transient expression. To prolong the expression, we developed a binary system whereby the transgene in the substrate BV was excised by the recombinase (ΦC31o, Cre or FLPo) expressed by a second BV and recombined into smaller minicircle. The recombination efficiency was lower by ΦC31o (≈40-75%), but approached ≈90-95% by Cre and FLPo in various cell lines and stem cells [e.