Autonomous pigmentation of epithelial cells

The pigmentation of the skin protects the body against ultraviolet radiation and determines how it is visually perceived by members of the own and other species. The pigment of the skin, melanin, is produced by cells known as melanocytes and subsequently transferred to epithelial cells. This mechanism of skin pigmentation is conserved in humans and other vertebrates. Another, so far uncharacterized mode of epithelial pigmentation is active in specialized skin structures of amphibians, such as the claws of clawed frogs. This type of pigmentation does not depend on melanocytes, but occurs autonomously in epithelial cells. The aim of the project is to determine the mechanism, function and evolution of non- canonical pigmentation in amphibians. The study uses recombinant enzymes and gene editing in Xenopus frogs to investigate the molecular control of pigment formation. The specific suppression of non-canonical pigmentation allows to determine its role in the establishment of the material properties of skin appendages. This project defines a unique mode of epithelial pigmentation and helps to understand the evolutionary adaptations of amphibians.