Expression of tyrosinase gene in transgenic albino mice: the heritable patterned coat colors.

To elucidate the regulatory mechanism for tyrosinase gene expression in vivo, we microinjected a mouse tyrosinase minigene, mg-Tyrs-J, into the fertilized eggs of BALB/c albino mice. As a result, we obtained six pigmented founder mice that exhibited non-standard coat color variations as well as the wild-type phenotype. These founder mice were subsequently crossed with BALB/c albino mice to establish the transgenic lines. As a consequence, two primary lines and five sublines have been obtained from four of the six founder mice. We found that not only uniformly pigmented phenotypes but also patterned phenotypes were inherited by their descendants. The possible underlying mechanism of the patterned phenotypes is discussed.