FIG. 6.

Schematic representation of the ICP0 gene promoter region and the deletion present in ΔTfi. Top: Base pair numbers relative to the start site of the ICP0 mRNA (horizontal arrow at + 1). Shown are known or potential regulatory elements of the ICP0 gene. Within the 180 bp upstream of the RNA start site is the known Octa/TAATGARAT sequence that confers IE expression kinetics to ICP0 (marked with asterisks), sp1 binding sites, a CAT box, an OLF-1 site, an ICP4 binding site, and a TATA box. Other sites with homology to known factor binding sites, including four additional potential TAATGARAT sites (labeled with question marks), are also indicated. Vertical arrows indicate the limits of the deletion in the ICP0 promoter in the ΔTfi mutant.