CRISPR/Cas9-Mediated Disruption of Fibroblast Growth Factor 5 in Rabbits Results in a Systemic Long Hair Phenotype by Prolonging Anagen

The study used CRISPR/Cas9 to disrupt the first exon of the FGF5 gene in rabbits, resulting in a systemic long hair phenotype by prolonging the anagen phase of the hair cycle. This confirmed FGF5 as a negative regulator of hair growth. The FGF5-/- rabbits exhibited decreased hair fiber diameter and a higher proportion of hair follicle clusters compared to wild-type rabbits. The long hair phenotype was associated with decreased BMP2/4 pathway signaling and increased VERSICAN pathway signaling. These findings suggest potential applications in fur production and provide a model for studying long hair mechanisms.