The Research Of Regulatory Mechanisms Of Dlk1and Meg3Skeletal Muscle Development Of Mice

Imprinted genes play important roles in muscle development and growth in mice.Genomic imprinting is an epigenetic modification process that leads to parent-specificgenes to be expressed. In general, imprinted genes are clustered in the chromosometogether, suggesting that the imprinting mechanism occur upon local chromosomedomains rather than individual genes. These clusters are also often involved with longnon-coding RNAs (lncRNAs), whose expression on the same allele is correlated withrepression of the linked protein-coding gene. The delta-like (Dlk1)-Dio3locus, awell-known imprinted gene cluster, is regμlated by its differentially methylated region(DMR) via an undefined mechanism. The imprinted gene clusters within the delta-like(Dlk1)/Dio3domain are found on chromosomes7in mouse. The1-Mb clusterconsists of three paternally expressed protein-coding genes (Dlk1, Rtl1, and Dio3),four maternally expressed ncRNAs (Gtl2, anti-Rtl1, Rian and Mirg) and somemicroRNAs (miRNAs). In our study, lncRNAs and genes were screening by chip, toprove that the various lncRNAs and genes are associated with the muscledevelopment of mice.Using chip screening method to obtained lncRNAs and encoding genes, the dataof chip screening results including Dlk1-Dio3region (imprinting genes Dlk1, longnoncoding RNA-Meg3and long noncoding RNA-Mirg), this article selects the markDlk1and Meg3gene as the research object, various proved Dlk1associated with miceskeletal muscle development. Meanwhile, the relationship of DNA methylationtransferase (Dnmts) and Dlk1and the relationship between Dlk1and signal pathwaysrelated to skeletal muscle were analyzed in the differentiation and demethylation inC2C12cells. The function of Meg3was research in C2C12cell.The results were as follows:1, The detection of skeletal muscle in mice with chip0and differences of the expression of60days after birth. It is found that imprintinggenes Dlk1and Meg3expression has significant differences.2, Dnmts (Dnmt1,Dnmt3a and Dnmt3b) mRNA transcription level and protein expression level in miceafter the birth of0,10,20,40and60days showed a trend of gradual decline in skeletal muscle of mice.3, Dlk1, Smad1, Notch1, Myog and Smad2proteinexpression level in different period of the differentiation of C2C12cells GM, DM1and DM2as a rising trend, but on the contrary, Dnmt3a protein expression levelsshowed a trend of decrease.4, Dlk1protein expression in the differentiation of C2C12cells or to deal with the methylation, significantly increased the expression of skeletalmuscle differentiation markers MHC, and promoted the muscular tube of C2C12cellsdifferentiation.5, Meg3were expressed in the development process of skeletal musclein mice, but after the birth of the expression of0to10days in skeletal muscledevelopment quantity is significantly higher than the expression of20to60days;6.Meg3differentiation has a promoting effect of C2C12cells;7. Meg3can inhibit theproliferation of C2C12cells.To sum up, Dnmts expression can be reduced by promoting the expression ofDlk1, raised the activity of the Smad1and Notch signal pathway, thus promote thedifferentiation of skeletal muscle cells in mice. In addition, Meg3can promote thedifferentiation of C2C12cells, but inhibit the proliferation of C2C12cells.