Identification Of MiRNAs In Adipose Tissues From Two Breeds Of Cattle And Bioinformatics Analysis Of Bta-miR-320a

Wagyu and Holstein are two of world famous cattle breeds with significant difference in fat deposition, which can provide good materials for the study of adipose accumulation. To identify miRNAs regulating fat deposition and provide theoretical bas is for related research, RNA-Seq technology was used to compare the miRNA transcriptome profiles between two breeds. In this experiment, back subcutaneous fat of five Wagyu and five Holstein cattle selected from healthy individuals during the period of slaughter were sampled. Two small RNA librar ies, W and H, representing each species(from a pooling of 5 Wagyu, 5 Holstein) were constructed, then Illumina sequencing and bioinformatics analysis were performed. 10974628(88.32%) and 9417372(85.96%) clean reads from W and H librar ies were obtained respectively and 17 differentially expressed known and 15 novel miRNAs were identified in total. 1345 genes were predicted to be target of those 17 dysregulated known miRNAs. It seems that all the target genes were involved in fatty acid metabolic process, glycerolipid metabolic process, triglyceride metabolic process, regulation of cell cycle etc. after GO enrichment analys is. Five signif icant pathways such as Glycerophospholipid metabolism, Notch signaling pathway and PPAR signaling pathway may regulate fat deposition. In conclusion, we assumed that differentially expressed miRNAs like bta-miR-30 f, bta-miR-196 b, bta-miR-320 a, bta-miR-874 etc. regulated the biological processes such as fatty acid metabolic process and pathways, for example, PPAR signaling pathway through the inhibition of their target genes, and then influenced fat accumulation.The prediction and analys is of bta-miR-320 a target genes by bioinformatics were performed to explore its effect on the deposition of fat in cattle. Bioinformatics tools such as Promoter Scan, TargetScan, DAVID, Cytoscape et al and databases, for example, miRBase, Ensemble, NCBI, miRWalk et al were used to perform the prediction of the transcription factor binding sites, the analysis of its target genes, involved GO and KEGG Pathway. As a result, miR-320(a) is very conservative in various species. There are many different transcription factor binding sites in the bta-miR-320 a promoter area. Eighty-four target genes are obtained which involved in multiple biological processes such as negative regulation of cell differentiation, regulation of cell cycle and negative regulation of growth etc. and participated in p53, cell cycle and MAP K signaling pathway et al. We assumed that bta-miR-320 a is regulated by diverse transcription factors, and it can regulate the adipocyte differentiation and fat deposition in cattle by post transcriptional inhibition of its target genes involved in p53, cell cycle and MAPK signaling pathway.