Meeting Abstract

P3.207  Tuesday, Jan. 6  Rapid Cold-Hardening Protects Against Cold-Induced Apoptosis: Role of Bcl-2 Protein KAWARASAKI, Y.*; YI, S.-X.; LEE, ; Miami University, Oxford, Ohio; Miami University, Oxford, Ohio; Miami University, Oxford, Ohio kawaray@muohio.edu

Rapid cold-hardening (RCH) describes an extremely swift acclimation response to low temperature stress. A brief acclimation to a moderately low temperature dramatically increases insect survival to a subsequent cold exposure that would be lethal otherwise. Recently, it was reported that chilling injury induces apoptotic cell death, while the RCH response significantly reduces the number of apoptotic cells. The possible involvement of anti-apoptotic Bcl-2 protein family was proposed since RCH preserved its expression level of these proteins, while it was reduced by cold shock. We investigated the protective role of the Bcl-2 protein, Buffy, against cold-induced apoptosis during RCH, using a mutant strain of Drosophila melanogaster that lacks expression of this Bcl-2 protein. This mutant strain showed significantly lower survival (5.4 +/- 2.1%) after a cold shock treatment of -5.5°C for 2 h, compared to wild type flies (65.7 +/- 4.8%). In addition, the RCH response in the Buffy mutant strain was compromised; in wild type flies, RCH (5°C for 2 h) significantly increased survival after cold shock (-6°C for 2 h) from 4.0 +/- 2.8 to 81.6 +/- 5.5%, whereas survival rates only increased from 0 to 16.0 +/- 5.2% in the Buffy mutant strain. The TUNEL assay was used to determine whether the reduced capacity for RCH was associated with increased apoptosis in the Buffy mutant strain. In addition, Western-blotting was used to investigate how cold shock and RCH treatment affects the protein expression of this Bcl-2. Our initial results suggest that the anti-apoptotic Bcl-2 protein plays a role during RCH for protection against cold-induced apoptosis. Supported by NSF grant IOB-0416720.