Pax and vertebrate development.

Pax genes encode transcription factors sharing a highly conserved sequence, the paired box. Their temporally and spatially restricted expression patterns during development indicate that Pax genes are involved in important steps of nervous system formation. Mutations in Pax genes have been correlated with three mouse mutants (undulated, splotch, small eye) and two human diseases (Waardenburg syndrome, aniridia). Recent data demonstrated that deregulation of Pax genes contributes to tumor formation.