Structure, function and regulation of p63 and p73

The p53 tumor suppressor gene is one of the most frequently mutated genes i n human cancers.(1) p53 is a sequence-specific transcription factor and pla ys a critical role in activating the expression of genes involved in cell c ycle arrest or apoptosis under conditions of genotoxic stress.(2,3) For ove r two decades, p53 was thought to be the only gene of its kind in the verte brate genomes, This strong conviction, which was widely accepted in the p53 field, has now been proven to be incorrect. Two genes, referred to as p63 and p73, have been found to encode proteins that share a significant amino- acid identity in the transactivation domain, the DNA binding domain, and th e oligomerization domain with p53, In the short period since their cloning, a number of investigators have reported on the structure, the function and the regulation of p63 and p73, This review summarizes the current informat ion on the p63 and the p73 genes, with a focus on the differences between t he three members in this newly defined p53-gene family.