Melanogenesis in melanoma cells in tissue culture.

The relationship between cell proliferation and differentiation was studied using C341 cells' isolated from a culture cell line of mouse melanoma B-16. The C341 cells' rate of melanin formation is intimately related to active cell proliferation. The cells were examined with light and electron microscopes on the 4 th day of cultivation when the cells were proliferating exponentially and on the 7 th day when the culture was in the stationary phase. The 4-day-old culture consisted of dark, light and melanosome-containing cells. Melanosomes, mostly in the early stages of development, were found to be present in the light cells as well as in the melanosome-containing cells. In cells of the 7 th day culture, there were numerous melanosomes in various developmental stages and also melanosome complexes. The morphological evidence obtained is compatible with the biochemical evidence previously recorded.