CircMED17 regulates bovine adipogenesis and fat deposition via mediating the proliferation and differentiation of bovine adipocytes

Fat deposition is a key factor influencing beef quality. Therefore, understanding the regulatory mechanisms of adipogenesis is crucial for improving meat production traits in cattle. Circular RNAs (circRNAs) have emerged as important post-transcriptional regulators in various biological processes, including adipocyte differentiation. In our study, circular RNA mediator complex subunit 17 (circMED17) was identified as a stable, nuclear-localized circRNA derived from exons 2 and 3 of the MED17 gene, with its expression markedly upregulated during bovine preadipocyte differentiation, suggesting its potential role in adipogenesis. Functional analyses revealed that circMED17 inhibits preadipocyte proliferation and apoptosis while promoting differentiation and lipid accumulation. Mechanistically, circMED17 exerts dual regulatory effects by sponging microRNA-146b (miR-146b) as a competing endogenous RNA (ceRNA) and by directly interacting with the transcription factor GATA-binding protein 2 (GATA2). Importantly, the in vivo overexpression of circMED17 in obese mice increased subcutaneous fat deposition, confirming its pro-adipogenic role. Collectively, the findings reveal a previously unreported dual mechanism of circMED17 in bovine adipogenesis and highlight its potential as a molecular target for improving beef quality through genetic and breeding strategies.