Figure 3. Cytochrome c release in p65 null cells. (A) p65 null (vector) and reconstituted cells were treated with 10 μM etoposide or 5 mJ UV-irradiation in the presence of the caspase inhibitor, zVAD-fmk (50 μM) for 18 hr and then fixed and stained with a specific antibody for native cytochrome c. An Alexa Green coupled secondary antibody was used to reveal the localization of cytochrome c. (B) Results are expressed as percentage of cells showing cytosolic cytochrome c.