Screening Of Fatty MiRNAs In Beef Cattle And The Expression Of MiR-26a In Different Parts

MicroRNAs(miRNAs)are non-encoding,single-stranded RNA molecules of about 20-24 nucleotides in length encoded by an endogenous gene that can regulate the translation of proteins by the RNA-induced silencing complex or degrade mRNA.Expression,more and more in vivo and in vitro experiments have confirmed that miRNAs play a very important role in fat formation.This study used Yanbian yellow cattle as the research object,collected 60 head muscles of Yanbian Yellow cattle that had been fattened up to 30 months old under the same conditions,and measured the content of intramuscular fat respectively.After statistical analysis,the content of intramuscular fat was extremely significant.The differential individuals were divided into high-fat group and low-fat group.Three high-fat and low-fat groups were selected for miRNA-seq and RNA-seq,so that miRNAs related to fat deposition were screened for GO analysis and KEGG.Analysis and application of miRanda biological software to predict its possible target genes,then the qRT-PCR validation of the sequencing results,and finally analyze the expression of miRNA-26a in Yanbian yellow cattle different muscle tissue.Further clarify the role of miRNA in the regulation of intramuscular fat growth and development in animal body,provide theoretical basis for the genetic mechanism of Yanbian yellow beef quality traits and high-grade beef production.The main results of this study are as follows:1.The miRNA-seq results of longis simusdorsi muscle tissue in high-and low-adipose group indicated that a total of 327 miRNAs were co-expressed in longissimus dorsi muscle of high-and low-adipose groups.The differential expression analysis of known miRNAs revealed that 33 miRNAs exist in 33 high and low-adipose groups.Differential expression,of which 8 up-regulated 25 down-regulated expression in the high-fat group.2.Combined analysis of miRNA-seq and RNA-seq combined with literature reports showed that 33 differentially expressed miRNAs predicted a total of 20 potential target genes.GO and KEGG analysis:Target genes for differential miRNAs belong to 10 biological processes;5 cell components;10 molecular functions.Differential target genes of differential miRNAs belong to five metabolic pathways(P<0.05).The potential role of target genes for differential miRNAs in fat deposition and other biological processes further validated the sequencing results.3.Select 3 of the differentially expressed miRNAs to upregulate miRNAs:bta-miR-22-3p,bta-miR-26a,bta-miR-182,and 2 down-regulated miRNAs:bta-miR-381 and bta-miR-100.Four non-differentially expressed miRNAs:bta-miR-122,bta-miR-375,bta-miR-543,and bta-miR-34a.The miRNA-seq results were validated.The results showed that the validated miRNAs were high and low in fat.The multiples of differences between the groups reached a significant level,consistent with high-throughput results,indicating that the test results are reliable.4.Selected miR-26a in the high and low fat group in the eye muscle,upper brain,ribs,West cold,triangle cattle forest,five parts,using real-time fluorescence quantitative method to detect the expression in different parts.The results showed that miR-26a had the highest expression in the upper brain and the lowest expression in the ribs,and the difference was extremely significant(P<0.01).The expression of miR-26a in the high-fat group was higher than that in the low-fat group.