Model Description: A CreERT2-2xpA expression cassette was knocked into the Notch1 gene start codon site. Notch1 performs vital cell functions, such as proliferation, differentiation, apoptosis, and stem cell maintenance. When Notch1-CreERT2 mice are bred with mice containing loxP-flanked sequence, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the floxed sequences in NOTCH1 positive cells.