Herpesvirus proteins: DNA polymerase and pyrimidine deoxynucleoside kinase activities in temperature-sensitive mutants of herpes simplex virus type 2.

Eleven temperature-sensitive mutants of herpes simplex virus type 2 strain HG52 were examined for ability to induce DNA polymerase activity in BHK 21/C13 cells. All mutants induced DNA polymerase at a permissive temperature, (31 degrees C) and all DNA-positive mutants at a non-permissive temperature (38 degrees C). Three DNA-negative mutants induced no DNA polymerase (ts 6, ts 9) or very little DNA polymerase (ts 11), at a non-permissive temperature, while ts 1, also DNA negative, induced a little more DNA polymerase than wild-type, often at both temperatures. The DNA polymerase induced by ts 6 at 31 degrees C was temperature-sensitive in vivo, but only slightly so in vitro. These results were confirmed immunologically and suggest that HSV-2 codes for at least part of a DNA polymerase activity, necessary for infection, and that full expression of this enzyme involves at least three viral genes.