FIG. 3.

Steady-state RNA levels transcribed either from the US3 promoter with a wild-type or mutant CRS downstream of the R₂ enhancer element or from the enhancer-containing MIE promoter at early and late times after infection (h.p.i. [hours postinfection]). HFF cells were infected with approximately 5 PFU of RVgptR₂CAT or RVgptR₂crs⁻CAT per ml. Cytoplasmic RNA was harvested and analyzed by RNase protection assays as described in Materials and Methods. IE1-specific RNA from the MIE promoter and CAT-specific RNA from the US3 promoter are designated; IE1 and CAT probes not treated with RNase are also designated. Std, ³²P-labeled DNA molecular weight markers, positions of which are indicated in nucleotides. (A) RNase protection assay at early times after infection; (B) RNase protection assay at early and late times after infection.