Role of excision mechanisms of DNA repair in induction of apoptosis.

DNA repair and apoptosis lead to principally different final results: the first mechanism removes damages from DNA, restoring genome integrity; the second mechanism eliminates potentially dangerous cells harboring DNA lesions. The cells deficient in mismatch repair (MMR) demonstrate increased resistance (viability) to DNA-damaging agents due to decreased ability to undergo apoptosis. This means that mechanism of MMR both restores structure of DNA and generates a signal for apoptosis. DNA breaks and single strand gaps, which are temporarily produced by excision mechanism during DNA repair, are suggested to be the initial signals for apoptosis. However pathway involved in such signaling at least partially is independent of p53 function.