Comparative Physiology and Biochemistry
Effects of genic substitution at the pink-eyed dilution locus on the proliferation and differentiation of mouse epidermal melanocytes in vivo and in vitro
Article first published online: 8 FEB 2002
Copyright © 2002 Wiley-Liss, Inc.
Journal of Experimental Zoology
Volume 292, Issue 4, pages 351–366, 1 March 2002
How to Cite
Hirobe, T., Kawa, Y., Mizoguchi, M., Ito, S. and Wakamatsu, K. (2002), Effects of genic substitution at the pink-eyed dilution locus on the proliferation and differentiation of mouse epidermal melanocytes in vivo and in vitro. J. Exp. Zool., 292: 351–366. doi: 10.1002/jez.10051
- Issue published online: 8 FEB 2002
- Article first published online: 8 FEB 2002
- Manuscript Accepted: 22 OCT 2001
- Manuscript Received: 7 MAY 2001
- Ministry of Education, Science and Culture, Japan. Grant Numbers: 10670812, 12670844
Cells positive to the dopa reaction (melanocytes) as well as to the combined dopa–premelanin reaction (melanoblasts and melanocytes) in the epidermis of C57BL/10JHir-p/p (pink-eyed dilution) mice were fewer and less reactive than in C57BL/10JHir (black, P/P) mice, suggesting that the proliferation and differentiation of p/p melanocytes are inhibited. To confirm the inhibitory effects of p gene on the proliferation and differentiation of epidermal melanocytes, we cultured epidermal cell suspensions of neonatal skins from P/P and p/p in a serum-free medium. The proliferation and differentiation of p/p melanoblasts/melanocytes in primary culture were greatly inhibited as compared to P/P melanoblasts/melanocytes. The morphology of p/p melanoblasts/melanocytes cultured in melanocyte growth medium, though non-pigmented, was similar to P/P melanocytes; namely, dendritic, polygonal, or epithelioid. About 8% of p/p cells cultured in melanocyte growth medium were positive to the dopa reaction, and about 25% were reactive to the combined dopa–premelanin reaction. Eumelanin content in p/p was extremely reduced compared to P/P. The immunocytochemical staining of p/p melanoblasts/melanocytes revealed that they are negative to tyrosinase, but reactive to tyrosinase-related protein (TRP)-1, TRP-2, and c-kit. However, the reactivities in p/p were lower than in P/P. Although the differentiation of p/p melanoblasts was not induced by endothelin (ET)-1, ET-2, and ET-3, the proliferation of p/p melanoblasts was stimulated by them. These results suggest for the first time that p gene exerts its influence on the proliferative activities of mouse epidermal melanoblasts by affecting the regulatory mechanisms dependent on the function of ETs. J. Exp. Zool. 292:351–366, 2002. © 2002 Wiley-Liss, Inc.