Initiator elements and regulated expression of the herpes simplex virus thymidine kinase gene

Regulated expression of thymidine kinase mRNA in herpes simplex virus mutants harboring thymidine kinase promoters that lacked functional TATA boxes was largely unaffected by additional sequence alterations around the transcriptional start site. A strong initiator element increased the regulated expression of a TATA-containing promoter by 50% but did not affect that of the TATA-less promoter. Thus, initiator elements exert only small effects in this promoter context.