HIROBE Tomohisa Division of Biology and Oncology, National Institute of Radiological Sciences, Senior Researcher, 生物影響研究部, 主任研究官 (10111238)
WAKA<ATSU Kazumasa Fujita Health University, School of Health Sciences, Assoc. Professor, 衛生学部, 助教授 (80131259)
|Budget Amount *help
¥3,200,000 (Direct Cost : ¥3,200,000)
Fiscal Year 1999 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 1998 : ¥1,800,000 (Direct Cost : ¥1,800,000)
The role of the agouti(A) gene in the development of epidermal melanocytes by comparing the activity of proliferation and differentiation of epidermal melanocytes from black (C57BL/10JHir) and agouti (C57BL/10JHir-A/A) mice in serum-free primary culture. There was no significant difference between agouti and black melanocytes in the proliferative activity as well as the reactivity to differentiation-stimulating factors. However, cultured agouti melanocytes possessed numerous stage "III" melanosomes than cultured black melanocytes under the electron microscopic observations. On the contrary, agouti melanocytes possessed a small number of stage "IV" melanosomes as compared to black melanocytes. The maturation of melanosomes form stage "III" to "IV" in agouti melanocytes is thought to be inhibited. To understand the mechanism of the action of the pink-dyed dilution (p) gene on the proliferation and differentiation of the epidermal melanocytes of pink-dyed dilution mice (C57BL/10Hir-p/p),L-tyrosine(L-try), the substrate of tyrosine, was supplemented to a serum-free metanocyte growth medium from the initiation of primary culture, and its effects were examined. In pink-eyed dilution melanocytes cultured with L-tyr, the numbers of melanosomes in all stage("I","II","III",and "IV")were dramatically increased, despite the limited numbers of stage "I","II",and "III" melanosomes in control culture. The content of pyrrole-2,3,5-tricarboxylic and (PTCA, degradation product of eumelanin)both in cultured cells and conditioned media was increased 2-fold. These results suggest that the pink-eyed dilution gene is involved in regulating the melanin synthesis as well as melanosome formation affecting the retention of L-try in melanosomes.