Use of the PBS2 uracil-DNA glycosylase inhibitor to differentiate the uracil-DNA glycosylase activities encoded by herpes simplex virus types 1 and 2.

The bacteriophage PBS2 encoded uracil-DNA glycosylase (UNG) inhibitor was examined for its effect upon the nuclear UNG activities of KB, HeLa, and Vero cells infected with herpes simplex virus (HSV) type 1 or 2 and mock-infected cells. UNG activity from HSV-1 infected cells exhibited the greatest sensitivity to inhibition by the inhibitor, while UNG activity from cells infected with HSV-2 exhibited the greatest resistance. This differential effect was dependent upon the virus, cell line, and buffer system used in the reaction. Furthermore, the PBS2 UNG inhibitor's differential effect, provides a means of distinguishing the herpesvirus UNG activities from one another, and from the cellular UNG activity. Therefore, this method of identification should prove to be useful for the purification and characterization of the viral enzymes from infected cell nuclear extracts.