Hamster Bcl-2 protein is cleaved in vitro and in cells by caspase-9 and caspase-3

Full-length cDNA of hamster bcl-2 (771 nt) was cloned by RT-PCR and inserte d into pGEX-4T-1 to produce the recombinant hamster Bcl-2 protein. The puri fied recombinant Bcl-2 protein (26.4 kDa) was used as a substrate for the a ctive human caspase-3 and caspase-9 in vitro. It is shown here that Bcl-2 i s efficiently cleaved by caspase-3 to a 23 kDa fragment. Although not posse ssing a putative caspase-9 cleavage site in its sequence, hamster Bcl-2 was also cleaved by caspase-9 into exactly the same 23 kDa cleavage product, i ndicating that cleavage occurred at the same site. Caspase-3- and caspase-9 -mediated cleavage of Bcl-2 was efficiently blocked by caspase-3 (zDEVD) an d caspase-9 (zLEHD) inhibitor, respectively. We also show that caspase-9/-3 -mediated cleavage of Bcl-2 occurs in vivo during apoptosis in CHO-HSV-TK c ells after exposure to the antiviral drug ganciclovir. (C) 2001 Academic Pr ess.