FIG. 4.

Immunoblot analysis of RNAP II large-subunit forms in Vero cells infected with ICP22 mutants. Vero cells were mock infected (lanes 1 and 2) or were infected with the various HSV-1 strains indicated (lanes 3 to 10) for 4 or 8 h (odd-numbered and even-numbered lanes, respectively) at an MOI of 10. Cells were scraped, washed, and lysed directly into SDS-PAGE sample buffer. Extracts were run on SDS–6% PAGE, transferred to filters, and probed with either MAb ARNA3 (A), which reacts with the body of the RNAP II large subunit, or MAb 8WG16 (B), which reacts with the large-subunit CTD. All lanes in panel A or B contain extracts from the same numbers of cells. Subunit IIa migrates at approximately 200 kDa; IIo migrates at approximately 240 kDa.