title: Pheomelanin production in the epidermis from newborn agouti mice is induced by the expression of the agouti gene in the dermis.
abstract: The present study was designed to clarify the role of the agouti gene in the regulation of the proliferation and differentiation of mouse epidermal melanocytes using serum-free primary culture of epidermal melanocytes from 0.5-d-old black (a/a; C57BL/10JHir) mice and congenic, agouti (A/A; C57BL/10JHir-A/A) mice. There was no significant difference in the proliferation or differentiation of melanocytes between a/a and A/A mice. However, the content of pheomelanin in culture media from A/A melanocytes was increased by L-tyrosine compared with a/a melanocytes. In addition, the content of the pheomelanin precursor, 5-S-cysteinyldopa, in culture media from A/A melanocytes was dramatically increased by L-tyrosine. Moreover, pheomelanin content in the epidermis from 3.5- and 5.5-d-old A/A mice was much higher than in a/a mice. Analysis of the A gene using reverse transcription-polymerase chain reaction revealed that cultured keratinocytes and melanocytes do not express the A gene. Moreover, the A gene was expressed in the A/A dermis of 0.5-, 3.5- and 5.5-d-old mice, but not in the a/a dermis nor in the A/A or a/a epidermis. These results suggest that A/A epidermal melanoblasts are influenced by the A gene from the dermis of neonatal mice, and are capable of synthesizing pheomelanin in the culture. Pheomelanin production in the epidermis from 3.5- and 5.5-d-old A/A mice may be induced by the expression of the agouti gene in the dermis.
authors.affiliation: Radiation Hazards 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: Sakae
authors.initials: S
authors.lastname: Takeuchi
authors.forename: Eri
authors.initials: E
authors.lastname: Hotta
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Wakamatsu
authors.forename: Shosuke
authors.initials: S
authors.lastname: Ito
mesh_terms: D054366:Agouti Signaling Protein; D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D003548:Cysteinyldopa / Q000096:biosynthesis; D020405:Dermis / Q000378:metabolism*; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis* / Q000235:genetics; D015603:Keratinocytes / Q000378:metabolism; D008543:Melanins / Q000096:biosynthesis*; D008544:Melanocytes / Q000378:metabolism*; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D054366:Agouti Signaling Protein; D036341:Intercellular Signaling Peptides and Proteins; D008543:Melanins; D012333:RNA, Messenger; C018362:pheomelanin; D003548:Cysteinyldopa