Structural analysis of dna related to apoptosis: Evidence for a specific lesion associated with DNA replication

In mammalian cells, fragmentation of DNA into nucleosomal lengths is widely recognized as the molecular criterion for apoptosis (Bursch et al., 1990). The phenomenon is of significance both as a means of monitoring apoptosis and providing a rationale, in terms of the activation of endogenous nuclease, for relating morphological to molecular change (Jones et al., 1989; Arends et al., 1990; Sorenson et al., 1990). The precise digestion pattern evident in preparations of DNA isolated from cells undergoing apoptosis due to a variety of stimuli is also a criterion for distinguishing so-called 'programmed cell death' from necrosis (Corcoran and Ray, 1992). The latter is characterized by random digestion of DNA mediated by lysosomal enzymes.