FUNCTIONAL-ANALYSIS OF THE SLATY GENE-PRODUCT (TRP2) AS DOPACHROME TAUTOMERASE AND THE EFFECT OF A POINT MUTATION ON ITS CATALYTIC FUNCTION

Slaty (slt), an autosomal recessive mutation that arose in YZ57/Ch mic e, results in the dilution of coat color and premature hair loss. Rece ntly, a gene encoding a homologue of the melanogenic enzyme tyrosinase (termed tyrosinase related protein 2 or TRP2) was cloned and was subs equently mapped to the slaty locus on chromosome 14. TRP2 was shown to function in melanogenesis as DOPAchrome tautomerase by means of the c atalytic activity of the immunopurified protein and in slaty mutant sk in samples. In this study, we generated an expression vector of a muri ne TRP2 encoding cDNA and are able to confirm its activity as DOPAchro me tautomerase. We further demonstrate that the slaty mutation dramati cally decreases the catalytic function of the protein.