Molecular Basis for Hair Loss in Mice Carrying a Novel Nonsense Mutation (Hr^rh-R) in the Hairless Gene (Hr)

Researchers identified a novel nonsense mutation in the hairless (Hr) gene in mice, termed Hr^rh-R, which caused significant hair loss and skin wrinkling due to reduced Hr mRNA levels from nonsense-mediated decay. Histological analysis showed dilated hair follicle infundibula filled with cornified material by 14 days of age. Gene expression profiling revealed upregulation of genes involved in keratinocyte differentiation and wound healing, indicating a loss of Hr's transcriptional corepressor function. The study suggested Hr's interaction with the Myc/Max superfamily influences hair follicle stem cell fate, providing insights into the molecular mechanisms of hair loss and the role of the Hr gene in hair follicle biology.