A common feature of SoxE group proteins, which includes Sox9 and Sox10, is their expression
in neural crest (NC) cells during embryonic development. NC cells are a transient
embryonic cell population that gives rise to most of the peripheral nervous system, chondrocytes
and osteoblasts of craniofacial structures, smooth muscle cells of the cardiovascular system,
and melanocytes, the pigmented cells of the skin. While Sox9 is expressed in
premigratory NC cells and in the pharyngeal apparatus, Sox10 is found in NC cells at the time
of their emigration and is essential for their self-renewal and survival. Loss of Sox10 results
in absence of most NC derivatives, whereas Sox10 haploinsufficiency causes Waardenburg
Hirschsprung syndrome, characterized by aganglionic megacolon, pigmentary abnormalities
and often deafness due to loss of sensory innervation. In the melanocytic lineage,
Sox10 is expressed during all stages of development as well as in the adult and is required in different
species for the generation and homeostasis of embryonic and adult melanocytes in vitro
and in vivo