Sl. No. Functions Mechanisms 1. Prevents the transmission of damaged genetic information from one cell generation to the next. Binding to a transcription factor called E2F. This prevents E2F from binding to the promoters of proto‐oncogenes such as c-myc and c-fos. Transcription of c-myc and c-fos is needed for mitosis to block the transcription factor needed to turn on the genes preventing cell division. 2. Initiates apoptosis if the damage to the cell is severe Works as an emergency brake on cancer development by killing cells that attempt to proliferate in oxygen‐deficient regions of tumors. 3. Transcription factor Represses transcription of one set of genes (several of which areinvolved instimulating cell growth) while stimulating expression of other genes involved in cell cycle control.By stimulating the transcription of the p21 gene (negative regulator of cyclin‐dependant kinases), p53 prevents cell proliferation.

Table 1: Functions of p53 [29].