Abstract
Fat deposition significantly impacts the meat yield and the meat quality of beef cattle, which is closely associated with the preadipocyte proliferation and differentiation. Bta-miR-493 is expressed differentially in the backfat of Qinchuan cattle of various ages, and it may be involved in the fat accumulation of beef cattle. However, the role and functional mechanism of bta-miR-493 in fat deposition are still unclear. Tissue-specific expression analysis showed that the level of bta-miR-493 was moderately abundant in the adipose tissues of beef cattle. Moreover, the expression of bta-miR-493 in perirenal fat, subcutaneous fat, and longissimus dorsi muscle of Japanese black cattle was significantly higher than that in Qinchuan cattle. EdU staining, cell counting assay, and Oil Red O staining indicated that bta-miR-493 promoted the proliferation of bovine preadipocytes but inhibited their differentiation. The dual luciferase assay and transcriptomic analysis confirmed that bone morphogenetic protein receptor 1A (BMPR1A) is a target gene of bta-miR-493. Moreover, rescue experiments showed that bta-miR-493 could promote bovine preadipocyte proliferation but inhibit their differentiation by targeting BMPR1A via the TGFβ/BMP and p38MAPK signaling pathways. Overall, our findings revealed a bta-miR-493-BMPR1A-TGFβ/BMP/p38MAPK regulatory axis that will serve as a theoretical foundation for the molecular breeding of beef cattle with high intramuscular fat deposition.