Boissy R E, Trinkle L S, Nordlund J J
University of Cincinnati College of Medicine, Department of Dermatology, OH 45267-0592.
Cell Differ Dev. 1990 May;30(2):129-45. doi: 10.1016/0922-3371(90)90081-7.
Neural-crest-derived melanocytes populate two anatomical sites in the chicken, the epidermis of regenerating feathers and the uveal tract of the eyes. These two anatomical populations of melanocytes differ morphologically and functionally. Morphologically, feather and uveal melanocytes synthesize structurally different pigment granules (melanosomes). Feather melanosomes are rod-shaped, 0.2 x 0.8 micron, whereas uveal melanosomes are larger and more oval, 0.6 x 0.9 micron. Functionally, feather melanocytes continuously synthesize melanosomes during feather regeneration, and transfer these melanosomes to neighboring keratinocytes. Ocular melanocytes, on the other hand, synthesize melanosomes until their cytoplasm becomes congested with melanosomes, at which time the melanocytes become melanogenically dormant and do not transfer granules to neighboring cells. Cultures of melanocytes established from neural tubes of Light Brown Leghorn chick embryos produce two populations of melanocytes containing small (0.45 micron) or larger (0.90 micron) melanosomes which resemble the two types described in situ. Both types of melanocytes emigrate from along the entire length of the neural tube during several embryonic stages. Melanocyte cultures developed from neural tubes of the Recessive White breed of chicken, which has tyrosinase-negative, feather melanocytes and pigmented, functionally normal uveal melanocytes, also develop a mixture of amelanotic and pigmented melanocytes which maintain their respective characteristics even after separation by flow cytometry and reculture. These findings suggest that epidermal and uveal melanocytes are two distinct sub-populations of melanocytes whose commitment to separate lineages can occur in culture in the absence of their respective target tissue environment.
神经嵴衍生的黑素细胞分布于鸡的两个解剖部位，即再生羽毛的表皮和眼睛的葡萄膜。这两个解剖部位的黑素细胞在形态和功能上存在差异。在形态上，羽毛和葡萄膜黑素细胞合成结构不同的色素颗粒（黑素小体）。羽毛黑素小体呈杆状，大小为0.2×0.8微米，而葡萄膜黑素小体更大且更呈椭圆形，大小为0.6×0.9微米。在功能上，羽毛黑素细胞在羽毛再生过程中持续合成黑素小体，并将这些黑素小体转移至相邻的角质形成细胞。另一方面，眼部黑素细胞合成黑素小体，直至其细胞质被黑素小体充满，此时黑素细胞进入黑素生成休眠状态，不再将颗粒转移至相邻细胞。从浅褐色来亨鸡胚胎神经管建立的黑素细胞培养物产生了两种黑素细胞群体，其含有小（0.45微米）或大（0.90微米）的黑素小体，类似于原位描述的两种类型。在几个胚胎阶段，这两种类型的黑素细胞均沿神经管的全长迁移出来。从隐性白羽鸡品种的神经管发育而来的黑素细胞培养物，该品种具有酪氨酸酶阴性的羽毛黑素细胞和有色素的、功能正常的葡萄膜黑素细胞，也会发育出无黑素和有色素的黑素细胞混合物，即使通过流式细胞术分离并重新培养后，它们仍保持各自的特征。这些发现表明，表皮和葡萄膜黑素细胞是黑素细胞的两个不同亚群，它们在没有各自靶组织环境的情况下，在培养中就可发生向不同谱系的分化。
