The p53 gene family in vertebrates: Evolutionary considerations.

The origin of the p53 gene family predates multicellular life since TP53 members of this gene family have been found in unicellular eukaryotes. In invertebrates one or two genes attributable to a TP53-like or TP63/73-like gene are present. The radiation into three genes, TP53, TP63, and TP73, has been reported as a vertebrate invention. TP53 is considered the "guardian of the genome" given its role in protecting cells against the DNA damage and cellular stressors. TP63 and TP73 play a role in epithelial development and neurogenesis, respectively. The evolution of the p53 gene family has been the subject of considerable analyses even if several questions remain still open. In this study we addressed the evolutionary history of the p53 gene family in vertebrates performing an extended microsyntenic investigation coupled with a phylogenetic analysis, together with protein domain organization and structure assessment. On the basis of our results we discussed a possible evolutionary scenario according to which a TP53/63/73 ancestor form gave rise to the current TP53 and a TP63/73 form, which in turn independently duplicated into two genes in agnathe and gnathostome lineages.