To determine if either EGR1 binding site mutation affected UL138 expression in the context of infection, we infected fibroblasts with TB40/E-WT, -ΔEGR1Site 1 or -ΔEGR1Site 2, and measured UL138, UL135, and IE1/IE2 protein levels at 48 hpi by immunoblot (Fig 9B). The gene discussed is EGR1; the disease is infection.