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

Bing Yao,Liangxue Lai,Nannan Li,Hongmei Liu,Yuxin Zhang,Huilin Pan,Zhanjun Li,Yuxin Xu,Xinyue Wang

doi:10.3390/genes11030297

Bing Yao, Liangxue Lai + Show 7 more

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https://doi.org/10.3390/genes11030297

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Abstract

Hair growth and morphology are generally regulated by the hair cycle in mammals. Fibroblast Growth Factor 5 (FGF5), which is a hair cycle regulator, has a role in regulating the hair cycle during the transition from the anagen phase to the catagen phase, and a hereditary long hair phenotype has been widely reported when FGF5 is mutated in humans and other species. However, there has been no such report in rabbits. Thus, the first exon of rabbit FGF5 was disrupted by the CRISPR/Cas9 system, and the phenotype of FGF5-/- rabbits was characterized while using hematoxylin and eosin (H&E) staining, immunohistochemistry, quantitative PCR, scanning electron microscopy, and western blotting. The results showed a significant and systemic long hair phenotype in the FGF5-/- rabbits, which indicated that FGF5 is a negative regulator of hair growth. In addition, a decreased diameter of the fiber and a higher area proportion of hair follicle clusters were determined in FGF5-/- rabbits as compared with the WT rabbits. Further investigation verified that prolonging the anagen phase in rabbits, with decreased BMP2/4 pathway signaling and increased VERSICAN pathway signaling, caused the systemic long hair phenotype. Taken together, these results indicate a systemic long hair phenotype by prolonging anagen in FGF5-/- rabbits, which could be widely used for Fur production and an ideal model for studying the mechanism of long hair in the future.

Highlights

The rabbit is an important livestock species that provides a variety of products, including fiber, meat, and hides
We discovered a sex-dominant pattern of growth in Fibroblast Growth Factor 5 (FGF5)-/- and WT rabbits
Two sgRNAs targeting the first exon of FGF5 were designed to mimic mutations in human [7], and Figure 1A shows the target sites

Summary

Introduction

The rabbit is an important livestock species that provides a variety of products, including fiber, meat, and hides. Rabbit hair is one of the preferred natural fibers used in textile industries [1]. The down hair length is a critical economic trait in wool production, as it is closely associated with wool productivity and yield. The molecular mechanisms regulating rabbit hair growth have remained elusive, hair fiber length is an important economic trait of rabbits in fur production [1]. Hair is produced from follicles as skin appendages that are unique to mammals, and hair is characterized by periodic regrowth [3,4]. The hair growth cycle can be typically defined as three phases: Genes 2020, 11, 297; doi:10.3390/genes11030297 www.mdpi.com/journal/genes

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