Inhibition of generation of authentic genomic termini of herpes simplex virus type 1 DNA in temperature-sensitive mutant BHK-21 cells with a mutated CCG1/TAF(II)250 gene.

A temperature-sensitive (ts) mutant from the BHK-21 hamster cell line, tsBN462, has a defect in progression of the G1 phase at the nonpermissive temperature of 39.5 degrees C. The ts mutation in tsBN462 is located in the CCG1 gene, encoding the general transcription factor TAF(II)250. In tsBN462 at 39.5 degrees C, infectious progeny of herpes simplex virus type 1 (HSV-1) was not produced and generation of authentic genomic termini of HSV-1 was inhibited. HSV-1 concatemers containing L components in two possible orientations were produced in tsBN462 at 39.5 degrees C; hence, the generation of authentic genomic termini seemed to be dispensable for inversion of the L component. As production of mRNAs of HSV-1 genes of three kinetic classes in the tsBN462 at 39.5 degrees C was comparable to findings under permissive conditions, the sequential and regulated manner in which HSV-1 gene expression is processed is likely to be maintained in the nonpermissive condition.