Fig. 2. Immunoblot analysis of AG05229 and HCA2 fibroblasts with or without the expression of HPV16 E6. Lysates were prepared from cycling cells (young), senescent cells (M1), cycling E6-infected cells (CyE6) and E6-infected cells at M^int (M^int) for both AG05229 and HCA2. Expression levels were compared for various cell-cycle components as indicated. Approximately equal amounts of cell lysate protein (23 µg top, 19 µg middle and 11 µg bottom panels, respectively) were loaded per lane as verified by India-ink staining; the HCA2 cells at CyE6 lane in the bottom panel is slightly overloaded. Molecular mass markers (M) are shown in kDa. The hyperphosphorylated forms of pRb are denoted by the small arrows.