The top-50 gene of DEGs.

<div> Endothelial lipase (LIPG), a member of the triglyceride lipase family, plays an essential role in human diseases and lipid metabolism. However, its function in goat intramuscular fat (IMF) deposition remains unclear. In this study, we investigated the role of the <i>LIPG</i> gene in IMF deposition by knocking down and overexpressing it in goat intramuscular preadipocytes. We successfully cloned the full-length <i>LIPG</i> gene, which spans 2,131 bp, including a 94 bp 5’ untranslated region (5’UTR), a 1,503 bp coding sequence (CDS), and a 534 bp 3’ untranslated region (3’UTR). Tissue expression profiles showed that <i>LIPG</i> is expressed in the heart, liver, spleen, Kidney, longest dorsal muscle, and small intestine tissues of goats. <i>LIPG</i> knockdown significantly inhibited both the proliferation of intramuscular preadipocytes and lipid deposition. Moreover, <i>LIPG</i> knockdown markedly decreased mRNA expression of <i>FASN, LPL, CPT1A, CPT1B, FABP3</i>, while increasing the mRNA expression of <i>ATGL, ACOX1, FADS1,</i> and <i>ELOVL6</i>. These findings were further corroborated through <i>LIPG</i> overexpression experiments. Using RNA sequencing (RNA-seq), we identified 1695 differentially expressed genes (DEGs) between the negative control (NC) and <i>LIPG</i> knockdown (Si-LIPG) groups, with KEGG pathway analysis revealing significant enrichment in the PPAR signaling pathway. Additionally, <i>LIPG</i> knockdown significantly upregulated the expression of both mRNA and protein levels of PPARα. The PPARα agonist WY14643 was able to reverse the enhanced lipid deposition induced by <i>LIPG</i> overexpression. In conclusion, our study highlights a key role for LIPG in the regulation of goat intramuscular preadipocyte proliferation and lipid deposition, potentially through the PPARα signaling pathway. These findings provide new insights into the regulatory mechanisms governing IMF deposition and suggest potential strategies for improving goat meat quality. </div>