c-Maf–expressing cells die by apoptosis. (A) c-Maf– and MEnT-containing cells show a sub-G1 peak indicative of apoptotic cell death. Positive control MEnT-containing (MEnT, top two panels) or c-Maf–containing (c-Maf, lower panels) that had been untreated or treated with ZnSO4 for 72 hours, stained with propidium iodide, and analyzed for DNA content by flow cytometry. Representative data is presented. (B) c-Maf– and MEnT-expressing cells show increased TUNEL staining. HL-60 clones overexpressing MEnT, CB6 vector, or c-Maf were treated with zinc for 48 hours (c-Maf, CB6) or 24 hours (MEnT), stained, and assessed by flow cytometry. Representative data are presented. (C) c-Maf– and MEnT-containing cells show DNA “laddering” characteristic of apoptosis. DNA was extracted from negative control CB6 (lanes 1 and 2), c-Maf–containing (c-Maf, lanes 3 to 6), or positive control MEnT-containing cells (lanes 7 to 9) that had been treated with ZnSO4 for the indicated time periods and separated by agarose gel electrophoresis.
