Genetic and biochemical diversity in the Pax gene family.

The mammalian Pax gene family comprises nine members that are characterized by a conserved DNA-binding motif, the paired domain, which was originally described in the Drosophila protein paired. Both loss- and gain-of-function studies reveal that Pax genes carry out essential roles during embryogenesis, and in some instances, may function as master regulatory genes. This review focuses on both genetic and biochemical aspects of the Pax family, and emphasizes important differences in the activity of individual Pax genes and their protein products.