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

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.

Effects of exogenous melatonin on expressional differences of immune-related genes in cashmere goats

“…However, the concerned changes became evident as differential expression of two groups of immune-related genes in blood and skin. Our previous study reported that tissue-specific module genes involved in 687 pathways, such as adaptive immune response, innate immune response, immune system development, and regulation of leukocyte migration, were upregulated in the blood compared with skin ( Chai et al, 2021 ). The functions involved immune-related GO terms were grouped for analysis in the blood.…”

“…Because the expression of many genes in the genome is regulated by TFs, we observed that the network included 24 TFs for target gene sets in the treatment group, and these 24 TFs simultaneously regulated the melatonin-dependent networks between the TFs and immune-related genes in cashmere goats. We previously reported that high-sulfur gene expression is important for wool growth regulation ( Chai et al, 2021 ). A total of 47 high-sulfur protein genes exhibited an interaction with TFs and cofactors with ASE in the skin of cashmere goat.…”

“…The accession number is CRA004598, which can be accessed from https://ngdc.cncb.ac.cn/gsa . Six cashmere goats were divided into two groups, including melatonin-implanted group (treatment group) and melatonin-nonimplanted group (control group), with 3 cashmere goats in each group ( Chai et al, 2021 ). During the experiment, 2 mg/kg body weight melatonin was implanted subcutaneously behind the ears of the treatment group goats, whereas no melatonin was implanted in the control group.…”

“…One month after implantation, scapula skin samples (size, 1 cm2) and venous blood samples were collected. Samples were quickly frozen in liquid nitrogen and were stored in a −80°C freezer ( Chai et al, 2021 ).…”

“…3 cashmere goats in each group (Chai et al, 2021). During the experiment, 2 mg/kg body weight melatonin was implanted subcutaneously behind the ears of the treatment group goats, whereas no melatonin was implanted in the control group.…”