Intramuscular fat deposition or marbling is essential for high quality beef. The molecular mechanism of adipogenesis in skeletal muscle remains largely unknown. In this study, we isolated Platelet-derived growth factor receptor α (PDGFRα) positive progenitor cells from fetal bovine skeletal muscle and induced into adipocytes. Using miRNAome sequencing, we revealed that bta-miR-23a was an adipogenic miRNA mediating bovine adipogenesis in skeletal muscle. The expression of bta-miR-23a was down-regulated during differentiation of PDGFRα+ progenitor cells. Forced expression of bta-miR-23a mimics reduced lipid accumulation and inhibited the key adipogenic transcription factor peroxisome proliferative activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα). Whereas down-regulation of bta-miR-23a by its inhibitors increased lipid accumulation and expression of C/EBPα, PPARγ and fatty acid-binding protein 4 (FABP4). Target prediction analysis revealed that ZNF423 was a potential target of bta-miR-23a. Dual-luciferase reporter assay revealed that bta-miR-23a directly targeted the 3′-UTR of ZNF423. Together, our data showed that bta-miR-23a orchestrates early intramuscular adipogeneic commitment as an anti-adipogenic regulator which acts by targeting ZNF423.

BackgroundFatty acid composition of muscle is an important trait contributing to meat quality. Recently, genome-wide association study (GWAS) has been extensively used to explore the molecular mechanism underlying important traits in cattle. In this study, we performed GWAS using high density SNP array to analyze the association between SNPs and fatty acids and evaluated the accuracy of genomic prediction for fatty acids in Chinese Simmental cattle.ResultsUsing the BayesB method, we identified 35 and 7 regions in Chinese Simmental cattle that displayed significant associations with individual fatty acids and fatty acid groups, respectively. We further obtained several candidate genes which may be involved in fatty acid biosynthesis including elongation of very long chain fatty acids protein 5 (ELOVL5), fatty acid synthase (FASN), caspase 2 (CASP2) and thyroglobulin (TG). Specifically, we obtained strong evidence of association signals for one SNP located at 51.3 Mb for FASN using Genome-wide Rapid Association Mixed Model and Regression-Genomic Control (GRAMMAR-GC) approaches. Also, region-based association test identified multiple SNPs within FASN and ELOVL5 for C14:0. In addition, our result revealed that the effectiveness of genomic prediction for fatty acid composition using BayesB was slightly superior over GBLUP in Chinese Simmental cattle.ConclusionsWe identified several significantly associated regions and loci which can be considered as potential candidate markers for genomics-assisted breeding programs. Using multiple methods, our results revealed that FASN and ELOVL5 are associated with fatty acids with strong evidence. Our finding also suggested that it is feasible to perform genomic selection for fatty acids in Chinese Simmental cattle.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-017-3847-7) contains supplementary material, which is available to authorized users.

No abstract