Three cDNA sequences of mouse type I keratins. Cellular localization of the mRNAs in normal and hyperproliferative tissues.

Researchers constructed cDNA libraries from normal mouse footpad epidermis and a squamous cell carcinoma to study type I keratin clones. They identified three keratin cDNA clones coding for two 52-kDa proteins and one 50-kDa protein. The 52-kDa keratins had serine-rich subdomains, while the 50-kDa lacked a distinct substructure. Despite sequence similarities, the 52-kDa keratins showed different expression patterns in mouse epithelia. Clone pkSCC 52 was found in basal cells, while pke 52 was in suprabasal cells. The study highlighted the complexity of interspecies keratin relationships and noted that the 50-kDa keratin mRNA was present in both hyperproliferative and normal hair follicle cells.