Spatiotemporal gene control by the Cre-ERT2 system in melanocytes

The organ‐specific and temporal control of gene activation/inactivation is a key issue in the understanding of protein function during normal and pathological development and during oncogenesis. We generated transgenic mice bearing a tamoxifen‐dependent Cre recombinase (Tyr::Cre‐ERT2) gene expressed under the control of a 6.1 kb murine tyrosinase promoter in order to facilitate targeted spatiotemporally controlled somatic recombination in melanoblasts/melanocytes. Cre‐ERT2 production was detected in tissues containing melanocytes. After tamoxifen induction at various times during embryogenesis and adulthood in a Cre‐responsive reporter mouse strain, genetic recombination was detected in the melanoblasts and melanocytes of the skin. Thus, the Tyr::Cre‐ERT2 transgenic mice provides a valuable tool for following this cell lineage and for investigating gene function in melanocyte development and transformation. genesis 44:34–43, 2006. © 2006 Wiley‐Liss, Inc.