Skin-Specific Expression of a Truncated E1a Oncoprotein Binding to p105-Rb Leads to Abnormal Hair Follicle Maturation Without Increased Epidermal Proliferation

In this study, researchers investigated the effects of a mutant Adenovirus E1a oncoprotein, NTdl646, on keratinocyte growth and differentiation in transgenic mice. The protein was expressed specifically in the skin using a keratin 5 promoter, resulting in two lines of mice with abnormal hair phenotypes, including short, crooked hair shafts and dystrophic or absent inner root sheaths. Despite these hair follicle maturation disturbances, the interfollicular epidermis remained normal, and there was no increase in spontaneous or chemically induced skin tumors. The study concluded that while the transgene disrupted keratinocyte maturation, it did not lead to increased epidermal proliferation or neoplastic growth.