Transcription of the herpes simplex virus genome in human cells

We have examined the details of the transcription of the herpes simplex virus (HSV) genome in HeLa cells using deoxyribonucleic acid-ribonucleic acid (DNA-RNA) hybridization. The following findings are reported. (i) Virus-specific RNA (vRNA) synthesized following onset of HSV-DNA replication (L-vRNA) is complementary to as much as 90% of the HSV genome. (ii) There is no significant class of virus-specific RNA synthesized later than L-vRNA. (iii) The vRNA synthesized prior to HSV-DNA replication (E-vRNA) is composed of two classes; one class comprising 75% of the total E-vRNA is found in large amounts as early as 45 min after infection, whereas the other class making up the other 25% of E-vRNA is found in only small amounts at 1.5 hr after infection. This second class of E-vRNA is found in amounts comparable to the first by 3.5 hr after infection. (iv) Inhibition of HSV-DNA synthesis results in the continued synthesis of E-vRNA, but there is no synthesis of L-vRNA. (v) Finally, there is no class of vRNA found in the nucleus that is not found associated with cytoplasmic polyribosomes either early or late after infection.