Effects of genic substitution at the agouti, brown, albino, dilute, and pink-eyed dilution loci on the proliferation and differentiation of mouse epidermal melanocytes in serum-free culture.
To examine the effects of coat-color genes on the proliferation and differentiation of mouse epidermal melanocytes, we cultured epidermal, cell suspensions derived from neonatal skins of C57BL/10JHir (black) and its congenic mice carrying agouti, brown, albino, dilute, and pink-eyed dilution genes in a serum-free medium supplemented with dibutyryl adenosine 3',5'-cyclic monophosphate. The proliferative rates of agouti, brown and dilute black melanocytes were similar to that of black melanocytes, while those of albino and pink-eyed black melanocytes were about one-half of that of black melanocytes. The morphology of albino and pink-eyed black melanocytes, though nonpigmented, was similar to black melanocytes; namely, dendritic, polygonal or epithelioid. Dilute black melanocytes also possessed the similar morphology, whereas their melanosomes were accumulated in the perinuclear region. Dopa-melanin depositions after dopa reaction in brown and dilute black melanocytes were greater than in black and agouti melanocytes. Although dopa-melanin depositions were not observed in albino melanocytes, about 8% of pink-eyed black melanocytes were positive to dopa reaction. Silver depositions after combined dopa-premelanin reaction in agouti, brown and dilute black melanocytes were similar to that in black melanocytes. Although albino melanocytes were devoid of silver depositions, about 25% of pink-eyed black melanocytes were positive to the reaction. Pyrrole-2,3,5-tricarboxylic acid (PTCA, degradation product of eumelanin) contents in agouti and dilute black melanocytes were slightly lower than in black melanocytes, while that in brown melanocytes was reduced to one-third. In contrast, PTCA contents in albino and pink-eyed black melanocytes were reduced to less than 0.5%. Aminohydroxyphenylalanine (AHP, degradation product of pheomelanin) contents did not differ among these melanocytes. These results suggest that the coat-color genes exert their influences on the proliferation and differentiation of mouse epidermal melanocytes by affecting tyrosinase activity, melanosome maturation and transport, and eumelanin synthesis.
Hirobe
T
T
Division of Biology and Oncology, National Institute of Radiological Sciences, Chiba, Japan.
Wakamatsu
K
K
Ito
S
S
D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000235:genetics; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism; D005838:Genotype; D006200:Hair Color / Q000235:genetics*; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL
D016895:Culture Media, Serum-Free; D008543:Melanins; D004295:Dihydroxyphenylalanine