FIG. 3.

Accelerated apoptosis in thymocytes from lck-PARP DBD transgenic mice is reflected by earlier cleavage of endogenous PARP and increased DNA laddering. (a) To monitor endogenous PARP cleavage, thymocytes of lck-PARP DBD transgenic mice and nontransgenic (non tg) littermates were cultured and either left untreated or irradiated with a single dose of 2 Gy. Samples were taken at the indicated time points after the stimulus and were analyzed by Western blotting. Equal loading of each lane was controlled by Ponceau staining (not shown). (b) To confirm that both X irradiation and treatment with MNNG induce apoptosis, genomic DNA prepared from thymocytes of lck-PARP DBD transgenic and nontransgenic control mice after treatment with MNNG was analyzed on agarose gels. The presence of nucleosomal DNA degradation indicates apoptosis.