The Homingbac baculovirus cloning system: An alternative way to introduce foreign DNA into baculovirus genomes

An in vitro baculovirus cloning system has been developed for direct cloning of foreign DNA into baculovirus genomes. This system is called the “Homingbac system” because it uses homing endonucleases. The Homingbac system was engineered into the baculoviruses AcMNPV, BmNPV, PxMNPV, RoMNPV, HaSNPV and HzSNPV. All Homingbac viruses were designed to retain the polyhedra phenotype so that they could be inoculated per os to insects. This is the first time a common in vitro baculovirus cloning system has been made for multiple baculovirus species that include both groups I and II nucleopolyhedroviruses (NPVs). In this study, the Homingbac system was demonstrated by directly cloning a PCR-amplified β-glucuronidase gene cassette into a parent Homingbac virus. This new collection of groups I and II NPV Homingbac viruses are a significant expansion of in vitro cloning technology and are new tools for making recombinant baculoviruses.