Homozygous K5Cre Transgenic Mice Have Wavy Hair and Accelerated Malignant Progression in a Murine Model of Skin Carcinogenesis

The study investigated the phenotype of homozygous K5Cre transgenic mice, which exhibited a wavy hair coat, curly whiskers, and disoriented hair follicles, leading to patches of alopecia over time. These mice were also smaller compared to wild-type controls, with fostering experiments suggesting a maternal defect in milk production. Examination of the mammary glands revealed fewer mammary branches and more quiescent alveoli units in lactating glands. When crossed with v-Ha-ras transgenic mice and subjected to a skin carcinogenesis model, the K5Cre+/+ mice showed no difference in papilloma formation but had an accelerated progression to malignancy and a higher frequency of malignant transformation. The unique phenotype of the K5Cre+/+ line was distinct from other known mutants, indicating a different molecular basis.