Targeted somatic mutagenesis in mouse epidermis

Gene targeting in the mouse is a powerful tool to study mammalian gene func tion. The possibility to efficiently introduce somatic mutations in a given gene, at a chosen time and/or in a given cell type will further improve su ch studies, and will facilitate the generation of animal models for human d iseases. To create targeted somatic mutations in the epidermis, we establis hed transgenic mice expressing the bacteriophage P1 Cre recombinase or the tamoxifen-dependent Cre-ERT2 recombinase under the control of the human ker atin 14 (K14) promoter. We show that LoxP flanked (floxed) DNA segments wer e efficiently excised in epidermal keratinocytes of K14-Cre transgenic mice . Furthermore, Tamoxifen administration to adult K14-Cre-ERT2 mice efficien tly induced recombination in the basal keratinocytes, whereas no background recombination was detected in the absence of ligand treatment. These two t ransgenic lines should be very useful to analyse the functional role of a n umber of genes expressed in keratinocytes. Copyright (C) 2001 S. Karger AG, Basel.