An anti-apoptotic role for the p53 family member, p73, during developmental neuron death

p53 plays an essential pro-apoptotic role, a function thought to be shared with its family members p73 and p63. Here, we show that p73 is primarily pr esent in developing neurons as a truncated isoform whose levels are dramati cally decreased when sympathetic neurons apoptose after nerve growth factor (NGF) withdrawal. Increased expression of truncated p73 rescues these neur ons from apoptosis induced by NCF withdrawal or p53 overexpression. In p73- /- mice, all isoforms of p73 are deleted and the apoptosis of developing sy mpathetic neurons is greatly enhanced. Thus, truncated p73 is an essential anti-apoptotic protein in neurons, serving to counteract the pro-apoptotic function of p53.