Figure 1: A. Replication-competent controlled HSV. An HSV genome is represented schematically in which replication-essential genes REG1 and REG2 were placed under control of a transactivator-responsive promoter (TRP) and a transactivator gene (TA) controlled by a promoter cassette (HSP70B/TRP) comprising an HSP70B and a TRP promoter was inserted. TRL, TRS: long and short terminal repeats; UL, US: long and short unique regions; IRL, IRS: long and short internal repeats. B. Illustration of an activated dual-responsive gene switch. eHSF1: host cell HSF1; SMR: Small-Molecule Regulator. The extra arrow beginning at the transactivator symbol (circle in a circle) indicates elimination/ dilution of transactivator.