FIG. 6.
Detection of Bcl-2 proteins by Western blot analysis of M1 and M1-D lysates. Proteins (20 μg/lane) were loaded onto 12% (A and B) or 15% (C) polyacrylamide gels, transferred to ProBlot membranes, and stained with 1:1,000 dilution of polyclonal rabbit antisera to Bcl-2 (A), Bcl-X (B), and Bax (C). The secondary antibody was peroxidase-labeled goat anti-rabbit Ig (1:1,000 dilution). Only undifferentiated M1 cells expressed high levels of Bcl-2. There was no change in expression of these proteins after infection (I). Differentiated M1-D cells expressed high levels of Bcl-XL. Bax-α was expressed only in M1-D cells, and expression was lost with IFN-γ treatment. Bax-β appeared to be ubiquitous. L929 cells are shown as a control. Western blots were repeated with two independently derived M1-D cell populations. Positions of molecular size markers (M) are shown on the left. U, uninfected.