Abstract
A cloned 3.5-kilobase fragment of herpes simplex virus type 1 DNA that contains the gene for the viral thymidine kinase was transcribed in vitro. Extracts from uninfected human cervical carcinoma HeLa cells produced 5 in vitro transcripts, 1 of which initiated at the in vivo start site for the thymidine kinase mRNA (an early viral message). A 2nd in vitro transcript initiated at or near the start site for a major late in vivo viral mRNA. The remaining 3 in vitro transcripts may correspond to minor in vivo mRNA species. Sequences similar to the T-A-T-A and C-A-A-T boxes, which may be involved in the control of transcription of a variety of viral and cellular genes, were found to precede the initiation site of each of the 5 in vitro transcripts. Considerable overlap of transcription units was observed.