Temporally controlled targeted somatic mutagenesis in mouse eye pigment epithelium.

To generate temporally controlled site-specific somatic mutations in the mouse eye pigment epithelium, we generated a TRP1-Cre-ER(T2) transgenic mouse line that expresses the tamoxifen-dependent Cre-ER(T2) recombinase under the control of the tyrosinase-related protein 1 (TRP1) promoter. Cre-ER(T2) transcripts were readily detected in the retinal pigment epithelium (RPE), and tamoxifen treatment of adult TRP1-Cre-ER(T2) transgenic mice induced efficient excision of floxed DNA in patches of RPE cells, in numerous epithelial cells of the iris and ciliary body, and in very few cells of the neural retina. Importantly, no excision was detected in any cells in the absence of tamoxifen treatment. Thus, the TRP1-Cre-ER(T2) mouse line provides a powerful tool to study in vivo gene functions in the mouse eye pigment epithelium.