Properties of the herpes simplex virus type 2 trans-inducing factor Vmw65 in wild-type and mutant viruses.

A temperature-sensitive mutant (ts13) of herpes simplex virus type 2 (HSV-2) has a mutation which causes in vitro thermolability of the virion. This mutation lies within the gene encoding a virion structural protein of Mr 65K which is known to stimulate immediate early transcription (the trans-inducing factor, 65KTIF). The results presented here show that the structural role of 65KTIF is essential. The electrophoretic mobility of the 65KTIF encoded by ts13 and a revertant of ts13 differed from that of the wild-type HSV-2 parent. Two monoclonal antibodies directed against 65KTIF were shown to react with two different epitopes on this polypeptide, one of which was altered by the mutation in ts13. No differences were observed in the phosphorylation status of 65KTIF from mutant- and wild-type-infected cells.