Genotoxic Stress Response/Cell Cycle
The human genome is exposed to potentially deleterious genotoxic events during every cell division cycle. This endogenous source of DNA damage results from cellular metabolism or routine errors in DNA replication and recombination. In addition, cellular and organismal exposure to exogenous genotoxic agents such as ultraviolet light, oxidative stress, and chemical mutagens, leads to a variety of nucleotide modifications and DNA strand breaks. In order to combat these attacks on the genome, the cell has evolved a response system that induces cell cycle arrest to allow sufficient time to repair the incurred damage. The genotoxic stress response system also activates the appropriate DNA repair pathway, or, in the case of irreparable damage, induces apoptosis.