Differential circRNA Screening and Identification of Subcutaneous Fat Tissue in Plateau-type Yaks under Different Feeding Methods

Background: In order to explore the differential expression of circular RNA (circRNA) in the subcutaneous fat tissue of Qinghai yaks under different feeding methods during the dry grass period and its regulatory mechanism. Methods: The present study adopted Illumina sequencing technology to sequence the transcriptome of subcutaneous fat tissue of Qinghai yaks naturally grazed and fattened by housed feeding during the dry grass period and used bioinformatics software to screen out the differentially expressed. The circRNAs were screened for differential expression using bioinformatics software. circRNAs related to fat metabolism were screened by GO function and KEGG pathway enrichment analysis of their source genes and three differentially expressed circRNAs were randomly screened and the expression of the circRNAs was verified by real-time fluorescence quantitative PCR (qRT-PCR). Result: Transcriptome sequencing results showed that a total of 628 differentially expressed circRNAs were obtained, of which 219 were up-regulated and 409 were down-regulated. GO functional enrichment analysis showed that the circRNAs in the free-grazing group originated from genes for major molecular constructs, cellular parts, organs, bioregulation and cellular processes, etc. KEGG pathway enrichment analysis showed that the circRNAs could be participate in signaling pathways such as phagosomes, protein digestion and absorption. qRT-PCR results showed that the expression levels of the three circRNAs were consistent with the sequencing results and the sequencing results were accurate and reliable. This experiment provides a molecular basis for further understanding of fat metabolism in yaks.