MELANOCYTES Normal skin tone is determined by: Melanin Carotene -orange-yellow pigment from some vegetables Hemoglobin-red coloring from blood cells in dermal capillaries Forms a supranuclear cap and protects nuclei from UV radiation Creates pigmentation of skin; tanning: UV light causes darkening of existing melanin and increased rate of melanin synthesis and transfer to keratinocytes Proliferation of melanocytes can produce moles.