Bovine bta-microRNA-1271 Promotes Preadipocyte Differentiation by Targeting Activation Transcription Factor 3.

ABSTRACT

Yanbian yellow cattle are one of the top five largest breeds of cattle in China. We had previously found that bta-miR-1271 is differentially expressed in the longissimus dorsi muscles of Yanbian yellow bulls and steers. However, whether bta-miR-1271 affects bovine fat formation is unclear. In this study, we used target gene prediction, dual-luciferase reporter assay, and transfection-mediated overexpression and inhibition of bta-miR-1271 in a culture of Yanbian yellow cattle preadipocytes to investigate the role of bta-miR-1271 in adipogenesis. We showed that bta-miR-1271 directly targets the 3'-untranslated region (3'-UTR) of the activating transcription factor 3 (ATF3) mRNA and downregulates its expression. Overexpression of bta-miR-1271 enforced by the miRNA mimics promoted triglyceride accumulation and significantly upregulated expression of the adipogenic peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT enhancer-binding protein α (C/EBPα) genes at both the protein and mRNA levels, as demonstrated by RT-qPCR and Western blot analyses. Conversely, inhibition of bta-miR-1271 expression produced the opposite effect. Our results show that bta-miR-1271 regulates differentiation of Yanbian yellow cattle preadipocytes by inhibiting ATF3 expression, which highlights the importance of microRNA-mediated regulation of adipogenesis. miR-1271 and its target gene(s) may provide a new research direction for investigating biological agents affecting intramuscular fat deposition in cattle.