FIG. 1.

Schematic of gH⁻TK⁻ recombinant viruses. All viruses were made gH⁻TK⁻ through the deletion of nucleotides 43771 to 47103 spanning the gH and TK coding sequences. Virus CS5 contains a CMV IE1 promoter-driven lacZ expression cassette replacing gH and TK sequences. Virus gH⁻TK⁻110LacZ contains an IE110 promoter-driven lacZ expression cassette inserted at the same locus. Virus CS1 contains an EMCV IRES-linked lacZ gene inserted between the HpaI sites within major LATs and was generated by the deletion of gH and TK from SC16 LβA. Virus VC1 is derived from coinfection of CS1 and C12 and consists of the CMV IE1 promoter-driven EGFP reporter gene cassette in the Us5 locus from C12 on the CS1 backbone. In VC1 and CS1, β-gal expression is driven by the endogenous LAP.