Melanization in albino mice transformed by introducing cloned mouse tyrosinase gene.

We introduced a mouse tyrosinase minigene, mg-Tyrs-J, in which the authentic genomic 5' non-coding flanking sequence was fused to a mouse tyrosinase cDNA, into fertilized egges of albino mice. Of the 25 animals that developed from the injected eggs, four mice exhibited pigmented hair and eyes. Histological analysis of the transgenic mice revealed that the melanogenesis was restricted to hair bulbs and eyes. These results suggest that this minigene encodes active tyrosinase protein and that its 5' flanking region contains the sequences regulating expression of mouse tyrosinase gene. This is the first report of a successful expression of tyrosinase gene and of pigment production in transgenic mice.