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. Additionally, K5Cre +/+ mice showed a significant decrease in mammary branching and more quiescent alveoli in lactating glands. When crossed with v-Ha-ras transgenic mice and subjected to a skin carcinogenesis model, the K5Cre +/+ mice did not differ in papilloma onset or size but showed an accelerated progression to malignancy and a higher frequency of malignant transformation. The phenotype of K5Cre +/+ mice was distinct from other known mutants, indicating a different molecular basis.