p53Induction as an Indicator of DNA Damage

p53 plays a central role in the cellular response to DNA damage. Induction of this protein is triggered by DNA breaks and correlates with their presence (1 ,2 ). In addition, p53 is upregulated by a number of different stress conditions including hypoxia, oncogene activation, viral infection, and ribonucleotide depletion (reviewed in (3 )). The ability of C-terminal domain of p53 to bind DNA ends (4 ,5 ), insertion/deletion mismatches (6 ), recombination intermediates (7 ) and gamma-irradiated DNA in vitro (8 ) implies that direct recognition of DNA lesions by p53 can play a role in its induction (9 ).