Melanocytes are the pigment producing cells found in our skin, the hair follicles and the inner ear. They are derived from neural crest progenitor cells that also give rise to sensory and sympathetic neurons, the Schwann cells of the peripheral nervous system as well as adrenomedullary cells. In vitro studies have shown that the ErbB neuregulin receptors are present in differentiated melanocytes and melanocyte precursor cell lines. To investigate the function of the neuregulin signaling pathway on melanocyte development in vivo I used an ErbB3 knock out mouse also carrying the LacZ reporter gene. The number of melanoblasts was significantly reduced at E10.5 but showed no differences at El 1.5 or E12.5 when compared to controls. A survival assay indicated that the initial decrease in melanocyte precursor numbers is not due to increased cell death. These results indicate that this pathway affects early melanocyte precursors.
