MCEE Promotes Intramuscular Fat Deposition in Pigs Through Regulating Mitochondrial Function

IMF is a key determinant of meat quality, influencing tenderness, juiciness and flavor, yet the mechanisms underlying its formation remain poorly understood. Previous studies performed whole-genome resequencing and GWAS on pigs with divergent IMF content, identifying MCEE as a candidate gene associated with IMF deposition. Subsequently, gain- and loss-of-function approaches were employed to investigate the role of MCEE in porcine intramuscular preadipocytes. Here, we isolated primary preadipocytes and subjected them to adipogenic induction. The overexpression of MCEE enhanced the proliferation and adipogenic differentiation of porcine intramuscular preadipocytes, whereas its knockdown exerted the opposite effect. Transcriptomic analysis revealed that DEGs were primarily enriched in pathways related to oxidative phosphorylation, mitochondrial dysfunction-associated disorders and others. Subcellular localization prediction indicated mitochondrial targeting of MCEE, and its expression level influenced mitochondrial function, including reactive oxygen species levels, mitochondrial membrane potential and permeability transition pore opening. Collectively, MCEE regulates IMF deposition by modulating mitochondrial function, and these findings provide a potential molecular target for improving meat quality.