Apoptosis is a well-recognized regulator of a cell populations size and str
ucture. Irreversible stages of apoptosis lead to activation of different en
zymatic cascades, changes in cell morphology and DNA fragmentation. However
, little is known about nuclear events which accompany the initial stages o
f apoptosis. These events are connected with introduction of limited amount
s of double strand breaks into genomic DNA, some of which may be subsequent
ly rejoined. We hypothesize here that the initial stages of apoptotic DNA f
ragmentation may be reversible and connected with the initiation of recombi
national events and certain chromosomal translocations. The factors influen
cing apoptosis reversibility and cell survival after delivery of apoptotic
stimuli may provide new insights into mechanisms of lymphocyte development
and tumorigenesis.