Mechanism of Myh3 gene regulation of intramuscular fat content in Beijing black pigs via the MAPK signaling pathway

BACKGROUND: Intramuscular fat (IMF) content is closely linked to meat tenderness and flavor. The Beijing Black pig, a renowned breed in China, serves as a valuable model for studying IMF traits, with implications for producing high-grade pork. RESULTS: This study identified six single-nucleotide polymorphisms (SNPs) in the myosin heavy chain 3 gene (Myh3) that were significantly associated with IMF traits in Beijing Black pigs. To elucidate the molecular mechanism by which Myh3 affects porcine IMF development, cellular-level studies were conducted. Myh3 interference inhibited the proliferation and differentiation of porcine intramuscular preadipocytes while promoting p38 protein phosphorylation, whereas Myh3 overexpression had the opposite effects. Further investigation using p38 mitogen-activated protein kinase (MAPK) pathway inhibitors and activators revealed that inhibiting the pathway alleviated the suppressive effects of Myh3 interference on differentiation, while activating the pathway reduced the promotive effects of Myh3 overexpression. CONCLUSION: Our findings demonstrate that Myh3 promotes intramuscular preadipocyte development by inhibiting the p38 MAPK signaling pathway, providing novel insights into the regulatory mechanisms of IMF development.