FIG. 5.

“Immediate-early” gene expression pattern of mutants prior to MT and ST protein expression in the presence or absence of serum factors. Cells were infected with wild-type, MT-Ter, Y6F, and A185 strains as described in the legend to Fig. 2. Early proteins produced during the early phase of the infections are shown. Given the low levels of viral proteins at these early times, a long exposure time was required, increasing the intensity of the cross-reacting cellular bands. The LT, MT, and ST bands are marked (*). Results after reprobing the same gel for the late proteins (VP1) are shown.