(d) CEM cells that either lacked Bcl-2 or expressed high levels of Bcl-2 received truncated Atg5 or GFP by lentiviral gene transfer. In the absence of Bcl-2, induction of apoptosis as assessed by DNA fragmentation was observed due to enforced expression of truncated Atg5 within two days. Apoptosis was largely blocked in cells expressing high levels of Bcl-2. GFP transfection did not affect viability of the cells in this system. 