Poly(ADP-ribose) synthesis: A marker of cellular stress.

Poly(ADP-ribosylation) is a post-translational modification of proteins that is implicated in many cellular processes, such as DNA repair, transcription and cell death. The investigation of the synthesis and accumulation of poly(ADP-ribose) (PAR) as a consequence of PARP overactivation in response to DNA damage/stress can provide the direct evidence for an involvement of poly(ADP-ribosy- lation) in damage response. In this respect, HeLa and HL60 cells have been stressed with different drugs, i.e. etoposide, actinomycin D, bleomycin and H2O2, or by growth factor deprivation, and the consequent accumulation of PAR was monitored. The detection of poly(ADP-ribose) within the cell could be a marker of apoptosis and of DNA damage/stress.