Effect of QSOX1 on cattle carcass traits as well as apoptosis and triglyceride production in bovine fetal fibroblasts and mammary epithelial cells

: QSOX1 (quiescin-sulfhydryl oxidase 1) is involved in various processes, including apoptosis and the development of breast diseases. Here, we investigated the effect of QSOX1 on the meat quality of Simmental cattle by analyzing the correlation between QSOX1 single nucleotide polymorphisms (SNPs), I2 204 C>T and I2 378 C>T, and certain meat quality traits. The effects of QSOX1 on triglyceride synthesis and cell apoptosis were further validated by gene silencing or overexpression in bovine fetal fibroblasts and mammary epithelial cells. The results showed that I2 204 C>T and I2 378 C>T had significant correlations with loin thickness, hind hoof weight, fat coverage, liver weight, heart weight, marbling and back fat thickness (P<0.05). QSOX1 overexpression also increased triglyceride production and suppressed apoptosis. In summary, QSOX1 is an important factor for meat quality, lipid metabolism, and cell apoptosis, indicating that QSOX1 could be used as a biomarker to assist in breeding cattle with superior meat.