P53 is a tumour suppressing gene that codes for a protein
that regulates the cell cycle to prevent abnormal cellular division. The
discovery of the p53 protein was found in the 1970’s by Professor Sir David
Lane (Jiang, 2011). When exposed to environmental stress p53 responds with
up-regulation, and results in programmed cell death or cell cycle arrest.
Apoptosis by p53 can be activated by transcription-dependent, or
transcription-independent factors. In transcription-independent pathways p53
translocates to the mitochondria resulting in the cell’s growth arrest;
whereas, transcription-dependent factors are regulated when p53 binds to the
promoter of a target gene, resulting in apoptosis.