An efficient method for precise gene substitution in the AcMNPV genome by homologous recombination in E. coli.

The RecA-mediated homologous recombination method was improved and used to direct gene replacement in baculoviruses. With this method, the p74 gene in the Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV) genome was substituted precisely by the p74 gene of Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV). In the recombinant bacmid, the AcMNPV p74 gene promoter controlled directly the expression of SpltMNPV p74 gene. Results of RT-PCR showed transcription of SpltMNPV p74 gene in the recombinant, implying the potential use of this easy and efficient method in baculovirus gene function research.