The oculocutaneous albinism type IV gene Matp is a new marker of pigment cell precursors during mouse embryonic development

Expression profile analysis demonstrated that the expression of membrane-associated transporter protein (MATP) varied similarly to the melanogenic enzymes dopachrome tautomerase (DCT) and tyrosinase related protein 1 (TYRP1) (Proc. Natl Acad. Sci. USA (2002) in press). Mutations in MATP result in pigmentation alterations in mice (underwhite, uw), in medaka (b-locus), and in man (Oculocutaneous Albinism Type 4, OCA4) (Nat. Genet. 28 (2001) 381; Am. J. Hum. Genet. 69 (2001) 981). Consistent with MATP acting in a pigment cell autonomous manner, in situ hybridization analysis demonstrated expression of murine Matp in the presumptive retinal pigmented epithelium starting at E9.5, and in neural crest-derived melanoblasts starting at E10.5. Matp expression is reduced in embryos mutated for microphthalmia-associated transcription factor (Mitf) (Cell 74 (1993) 395; J. Biol. Chem. 268 (1993) 20687), suggesting Mitf regulates Matp expression.