The neuregulin proteins (GGF/ARIA/NDF/Heregulin) are pleiotrophic growth and differentiation factors whose receptors, erb-B2, erb-B3, and erb-B4, are members of the epidermal growth factor receptor family of receptor tyrosine kinases. With western blots, we have examined the developmental and regional distribution of these receptors within the brain and sciatic nerve of chick embryos. The receptors erb-B2, erb-B3, and erb-B4 are developmentally and spatially regulated within the nervous system. In addition, cultures enriched for neurons or glia indicate that erb-B2 and erb-B4 are found in both neurons and glia, whereas erb-B3 is found in glia alone.

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