Directed Expression of a Chimeric Type II Keratin Partially Rescues Keratin 5-null Mice

The study explored the potential of a chimeric keratin protein, KRT8bc, to compensate for the absence of keratin 5 (Krt5) in mice, which is essential for skin integrity. Krt5-null mice, which usually experience severe skin fragility and neonatal lethality, were partially rescued by KRT8bc expression, with 47% surviving to adulthood. Despite forming intermediate filament bundles, KRT8bc could not fully replicate K5's functions, as evidenced by the development of alopecia and skin lesions in the rescued mice. The study highlighted the complexity of keratin protein interactions and the critical role of keratin IF self-organization in maintaining epidermal integrity.