title: Excess tyrosine rescues the reduced activity of proliferation and differentiation of cultured recessive yellow melanocytes derived from neonatal mouse epidermis.
abstract: The murine recessive yellow (Mc1r(e)) is a loss-of-function mutation in the receptor for alpha-melanocyte-stimulating hormone, melanocortin receptor 1 (Mc1r) and produces yellow coats by inducing pheomelanin synthesis in hair follicular melanocytes. However, it is not known whether the Mc1r(e) mutation affects the proliferation and differentiation of melanocytes. In this study, the proliferation and differentiation of recessive yellow epidermal melanocytes cultured in dibutyryl cyclic AMP-supplemented serum-free medium were investigated in detail. The melanocytes produced mainly eumelanin in this culture system. The proliferation of recessive yellow melanocytes was decreased compared with that of wild-type at the e-locus, black melanocytes. The differentiation of melanocytes was also delayed and inhibited in recessive yellow mice. Tyrosinase (TYR) activity and TYR-related protein 1 (TRP1) and TRP2 (dopachrome tautomerase, DCT) expressions were decreased and, in addition, the maturation of stage IV melanosomes was inhibited. Excess l-tyrosine (l-Tyr) added to the culture media rescued the reduced activity of proliferation of melanocytes. l-Tyr also stimulated TYR activity and TRP1 and TRP2 expressions as well as the maturation of stage IV melanosomes and pigmentation. These results suggest that the Mc1r(e) mutation affects the proliferation and differentiation of melanocytes and l-Tyr rescues the reduced proliferative and differentiative activities by stimulating TYR activity and TRP1 and TRP2 expressions as well as melanosome maturation.
authors.affiliation: Radiation Effect Mechanism Research Group, National Institute of Radiological Sciences, Anagawa, Inage-ku, Chiba 263-8555, Japan. thirobe@nirs.go.jp
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Hirobe
authors.forename: Hiyoyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: Shosuke
authors.initials: S
authors.lastname: Ito
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawa
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Soma
authors.forename: Masako
authors.initials: M
authors.lastname: Mizoguchi
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003994:Bucladesine / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000378:metabolism; D005260:Female; D019746:Intramolecular Oxidoreductases / Q000378:metabolism; D008297:Male; D008543:Melanins / Q000378:metabolism; D008544:Melanocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D020460:Melanosomes / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D014442:Monophenol Monooxygenase / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D044102:Receptor, Melanocortin, Type 1 / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000494:pharmacology*
chemical_list: D008543:Melanins; D044102:Receptor, Melanocortin, Type 1; C041877:eumelanin; D014443:Tyrosine; D003994:Bucladesine; D010088:Oxidoreductases; C064056:tyrosinase-related protein-1; D014442:Monophenol Monooxygenase; D019009:Proto-Oncogene Proteins c-kit; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase