Fig. 3. Role for {Delta}Np73 in apoptosis. This diagram depicts a role for {Delta}Np73 in neuronal apoptosis. The level of {Delta}Np73, the predominant form of p73 in certain developing neurons, is highest when maintained in NGF (left side of diagram). After NGF withdrawal (- NGF), {Delta}Np73 levels decrease and cells undergo p53-dependent apoptosis. The possible mechanism(s) by which {Delta}Np73 may inhibit p53 activities include: (1) occupying of p53 DNA-binding sites (gray rectangles); and (2) hetero-oligomerization of {Delta}N forms with wild-type p53. A similar model has been proposed for {Delta}Np63 during UV-induced apoptosis in keratinocytes (discussed in text).