Expression of a Ligninase by a New Hybrid Baculovirus with Expanded Host Range

We have generated and purified a new recombinant baculovirus with expanded host range. AcNPV DNA and BamHI-digested BmNPV DNA were co-transfected into Spodoptera frugiperda SF21 cells. Progeny viruses were used to infect BmN cells, which are normally resistant to AcNPV infection, in order to screen for recombinant viruses with cross-infectivity. A recombinant virus was isolated by plaque purification and analyzed. This isolate was able to infect, replicate and produce polyhedrin in both the SF21 and BmN cells. DNA restriction endonuclease analysis showed that it was a hybrid (HyNPV) of AcNPV and BmNPV. Co-transfection of this HyNPV virus with a transfer vector containing a ligninase H8 gene insert into SF21 cells yielded a recombinant baculovirus expressing the ligninase. When this recombinant baculovirus was used to infect either SF21 or BmN cells, ligninase proteins could be found in the lysed cells as well as in the cell culture media. We have thus demonstrated that this hybrid virus can be utilized in the generation of recombinant baculovirus expressing foreign proteins in two host cells which normally can not be infected by AcNPV nor BmNPV.