MOLECULAR CHARACTERIZATION OF A HUMAN TYROSINASE-RELATED-PROTEIN-2 CDNA - PATTERNS OF EXPRESSION IN MELANOCYTIC CELLS

Pigmentation in mammals is under complex genetic control. Amongst the genes involved in this process, those encoding tyrosinase and the tyro sinase-related-proteins 1 and 2 have been well characterized and share a number of features. Recently, the murine tyosinase-related-protein- 2 gene was shown to encode dopachrome-tautomerase activity and was map ped to the slaty locus. Human tyrosinase and tyrosinase-related-protei n-1 genes have been isolated and demonstrate a high degree of similari ty with their murine counterparts. However, there has been limited dat a regarding the existence of a human homologue for tyrosinase-related- protein-2 and its relationship to the other tyrosinase-related protein s. In this study, we report the molecular isolation of a cDNA encoding a human homologue of the murine tyrosinase-related-protein-2/dopachro me tautomerase. We have characterized its expression in human melanocy tic cells and have analyzed the relationship between dopachrome tautom erase and tyrosinase activities with the level of visible pigmentation in these cells. TYRP2 has been mapped to the chromosomal region 13q32 , thus extending a region of synteny with mouse-chromosome 14.