Pax3 and Vertebrate Development

Pax3, a transcription factor expressed in the developing embryo, is a critical factor for the proper formation of the mammalian nervous, cardiovascular, and muscular systems. In the mouse, spontaneous mutations in Pax3 resulting in complete loss of function have provided important models for the study of neural tube defects, congenital cardiac diseases affecting the outflow tract of the heart, and for the elucidation of the genetic pathways regulating myogenesis. In humans, haploinsufficiency of PAX3 results in deafness, pigmentation defects, and other neural crest-related abnormalities as well as variable-limb myopathy. An impressive array of genetic and molecular analyses have been employed in order to understand the function of Pax3, and these will be the focus of this review.