Screening And Identification Of Differentially Expressed LncRNA In Longissimus Dorsi Muscle,Subcutaneous Fat And Perirenal Fat Of Qinchuan Beef Cattle

Beef quality is affected by fat distribution and deposition,which regulated by a complex and precise gene regulatory network.At present,studies on the differential regulation of different parts of fat mainly focus on the m RNA level.In this study,to further explore the differences in lncRNA expression in different parts of fat,RNA-Seq was used to analyze the lncRNA expression profiles of the longissimus dorsi muscle,subcutaneous fat and perirenal fat of Qinchuan beef cattle.The possible functions of differentially expressed(DE)lncRNAs were explored,and lncRNAs that regulating fat deposition were screened and identified.The main research contents and results are as follows:1.Comparative lncRNA analysis between longissimus dorsi muscle,subcutaneous fat and perirenal fat of Qinchuan beef cattle.497,565,and 80 DE lncRNAs were identified between longissimus dorsi muscle and subcutaneous fat,longissimus dorsi muscle and perirenal fat,subcutaneous fat and perirenal fat,respectively(|log2Fold Change|>1,P<0.05).The cis-regulated target genes of DE lncRNAs were predicted,and the functional enrichment analysis of the target genes was carried out.The results showed that the DE lncRNAs in longissimus dorsi muscle and subcutaneous fat,and longissimus dorsi muscle and perirenal fat mainly regulate genes related to immune response,muscle development and lipid metabolism,while the target genes of DE lncRNAs between subcutaneous fat and perirenal fat mainly participate in physiological processes related to material transport and secretion functions.2.Screening and identification of lncRNAs regulating fat deposition in Qinchuan beef cattle.Combined with the expression level and the differential expression between tissues of lncRNAs by RNA-Seq,XR＿139735.5,MSTRG.5227.3 and MSTRG.26957.2,which were highly expressed in adipose tissues,were selected as candidate lncRNAs related to fat deposition in Qinchuan beef cattle.The expression of candidate lncRNAs in 14 tissues of 24-month-old Qinchuan beef cattle was detected,and the results showed that the expression of 3candidate lncRNAs were highest in subcutaneous adipose tissue.At the same time,they were significantly upregulated during the differentiation of bovine preadipocytes(P<0.05).Using si RNA interfered the expression of candidate lncRNAs in bovine preadipocytes,it was found that at 8 d of induction,interfering with the expression of MSTRG.5227.3 significantly inhibited the accumulation of lipid droplets in bovine adipocytes(P<0.01),which indicated that the lncRNA MSTRG.5227.3 had a potential effect on bovine fat deposition.3.Interfering with lncRNA MSTRG.5227.3 inhibits bovine preadipocyte differentiationThe lncRNA MSTRG.5227.3 adenovirus interference vector was used to stably downregulate the expression of lncRNA MSTRG.5227.3 to further explore the effect of lncRNA MSTRG.5227.3 on the differentiation of bovine preadipocytes.At 8 d of differentiation,the content of intracellular lipid droplets and triglycerides were significantly downregulated(P<0.05),and the expression levels of adipogenesis gene PPARγ and lipogenesis genes FABP4,ACCα,FASN,and SCD1 were significantly downregulated(P<0.05).The results indicated that interference of lncRNA MSTRG.5227.3 inhibits differentiation of bovine preadipocytes.In this study,the differences in the expression of lncRNA between the longissimus dorsi muscle,subcutaneous fat and perirenal fat of Qinchuan beef cattle were identified by RNASeq,and a novel lncRNA that could promote adipogenesis was successfully screened.The research could provide a certain reference for revealing the differential regulation mechanism of different parts of fat.