Role of Sulfur Metabolism Gene and High-Sulfur Gene Expression in Wool Growth Regulation in the Cashmere Goat.

Yuan Chai,Chun Li,Wenguang Zhang,Chunyan Jia,Yanyong Sun,Lili Guo,Le Zhou,Lingli Dai,Zaixia Liu,Bin Liu

doi:10.3389/fgene.2021.715526

Abstract

Sulfur, an essential mineral element for animals, mainly exists in the form of organic sulfur-containing amino acids (SAAs), such as cystine, methionine, and cysteine, within the body. The content, form, and structure of sulfur play an important role in determining the wool fiber quality. In addition, keratin-associated proteins, one of the most crucial wool fiber components, are rich in SAAs. However, sulfur metabolism from the blood to the skin and hair follicles remains unclear. In this study, we analyzed high-sulfur protein gene and sulfur metabolism genes in the cashmere goat and explored the effects of melatonin on their expression. In total, 53 high-sulfur protein genes and 321 sulfur metabolism genes were identified. We found that high-sulfur protein genes were distributed in the 3–4 and 144M regions of chromosome 1 and the 40–41M region of chromosome 19 in goats. Moreover, all year round, allele-specific expression (ASE) is higher in the 40–41M region of chromosome 19 than in the other regions. Total of 47 high-sulfur protein genes showed interaction with transcription factors and cofactors with ASE. These transcription factors and cofactors were inhibited after melatonin implantation. The network analysis revealed that melatonin may activate the sulfur metabolism process via the regulation of the genes related to cell energy metabolism and cell cycle in the skin, which provided sufficient SAAs for wool and cashmere growth. In conclusion, our findings provide a new insight into wool growth regulation by sulfur metabolism genes and high-sulfur protein genes in cashmere goats.

Highlights

The sulfur content directly affects the properties of wool fibers, including cashmere wool fibers
To run a complete search for identifying high-sulfur genes in the goat genome, two methods were used: We first searched the high-sulfur for protein sequences based on the published high-sulfur protein sequences in human (Khan et al, 2014) and sheep (Gong et al, 2016) and the Hidden Markov Model
53 genes were assigned as high-sulfur protein genes in cashmere goats (Supplementary Table 1)

Summary

Introduction

The sulfur content directly affects the properties of wool fibers, including cashmere wool fibers. SAA supplementation was found to significantly increase wool production and sulfur concentration. Daily supplementation with 2 g of cysteine or 2.46 g of methionine improved wool production per unit area of skin by 35–130% and wool sulfur content by 24–35% (Reis and Schinekel, 1961; Reis and Schinckel, 1963). Inhibition of the transsulfuration pathway can affect hair follicle development, skin thickness, and growth in broilers; this inhibition is associated with the upregulation of hepatic cystathionine synthase and cystathionine lyase mRNAs (Silva et al, 2018). Chicken epidermis in the cysteine-deficient group had thinner and shorter hair follicles with increased cystathionine synthase and cystathionine lyase mRNA expression—indicating a disruption in the transsulfuration pathway (Silva et al, 2019)

Methods

Results

Conclusion