1.4 kb of the Tyrosinase related protein 1 (Tyrp-1) promoter was fused to the SV40 Tag transforming sequences (including both small and large t antigens and the polyA tail. Approximately 8 copies of the transgene were inserted in the Y chromosome. Transgene expression was detected in the eye as early as E10.5. At 2-3 months of age, the SV40 large T antigen was strongly expressed in the eye, but only slightly in the skin of transgenic mice. No expression was detected in the kidney, liver, lung, spleen, or testis. Most mice were moribund by 3 months of age, primarily due to retinal tumors that had metastasized to the brain.