Dynamic analysis of skin transcriptome in Xinjiang goats and functional verification of ELOVL3 in dermal papilla cell proliferation

Xinjiang goats are important dual-purpose livestock, but their cashmere production is affected by environmental variation. The cycle of secondary hair follicles determines cashmere traits, and deciphering its regulatory mechanism under extreme climates is crucial for genetic improvement. Skin samples were collected from Xinjiang goats at six monthly time points across a full annual cycle. RNA-sequencing (RNA-seq) was used to profile gene expression, combined with differentially expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA) to identify key genes and modules associated with follicle cycle and climate factors. Functional validation of ELOVL3 was performed via immunofluorescence, overexpression, and interference assays in dermal papilla cells (DPCs). The results indicated that RNA-seq yielded high-quality data with 30,579 expressed genes. DEG analysis revealed 853 differential genes in May vs. July, with multiple keratin family genes co-expressed during March-July. WGCNA identified five modules correlated with follicle cycle, temperature, and precipitation. ELOVL3, a core gene in the temperature-related module, was expressed in DPCs and promoted DPCs proliferation by accelerating G1/S cell cycle transition. This study characterizes monthly dynamic transcriptional profiles in Xinjiang goat skin, identifies core genes correlated with hair follicle cycle progression and seasonal climatic variation, and verifies the function of ELOVL3 in promoting dermal papilla cell proliferation. The causal functions of the candidate genes in terms of climate adaptation still require further verification. The results provide theoretical support and candidate genes for cashmere quality improvement and stress-resistant breeding.