High level expression of DNA polymerases from herpesviruses.

The DNA polymerase genes of human cytomegalovirus (HCMV) and varicella-zoster virus (VZV) were inserted separately into the polyhedrin gene of Autographa californica nuclear polyhedrosis virus (AcNPV) by cotransfection of Spodoptera frugiperda (SF9) cells with baculovirus transfer vectors carrying the genes and AcNPV infectious DNA. Infection of SF9 cells with the recombinant viruses resulted in expression from the polyhedrin promoter of proteins of the expected Mrs. These proteins possessed DNA polymerase activities similar to that of the enzymes induced by the respective herpesvirus in infected cells, and were identified as HCMV and VZV DNA polymerase using inhibitors and specific antisera reactive with each enzyme.