Model Description: A IRES-iCre expression cassette was knocked into the Foxn1 gene stop codon site. The protein encoded by Foxn1 (forkhead box N1) gene is part of the forkhead family or "winged-helix" transcription factors that are important in developmental processes, immune system regulation, metabolism, cancer and aging. When crossed with a strain carrying a gene flanked by loxP sites, the flanked gene will be removed in thymic epithelial cell and keratinocytes.