Ovarian Stimulation Affects The Methylation Of H19 DMR In Mice Ovary

Epigenetics altered the expression of gene which did not change the DNA sequence. The factors which only changed the expression of gene was defined as epigenetic modification. DNA methylation、Genomic Imprinting were parts of Epigenetics. In Genomic Imprinting, single allelic gene expressed, the another did not expressed or expressed extremely weak. Therefore, Imprinting Gene hold this character. In the period of gametogenesis, Imprinting Gene could be erasued and rebuilded. If a link in the change period ocoured errors, embryo may appear defects, even though embryo died. Epigenetic mechanism included DNA methylation and histone modification change in the process of erasre 、 rebuilding and maintaining. However, the DNA sequence did not change, Imprinting Gene had an abnormal expression. DNA methylation included hypemethylaton and hypomethylaton. In histone modification, histone methylation ocour defect or lose. Recently, imprinting errors caused dieases in ART offsprings which were the result of Epigenetics. Now the machine is not clear and definite. Maybe involved parents’ fertility、ovulation stimulate、IVF、ICSI、ET and so on. Many reserches about H19 which was one of Imprinting Gene. H19 gene had been identified on human chromosome 11 and on mice 7 and length 3489 bp. It is only expressed for the RNA and not translated into protein. the specific functions of H19 have not yet been studied clearly.OBJECTIVES: To investigate the effects of ovulation stimulate to the methylation status of H19 differentially methylated region(DMR) in mice ovary.METHODS: In this study, there were two groups: the study group and the control group. All the female mice are in puberty. In the study group, all the mice were ovulation stimulate by Pregnant Mare Serum Gonadotropin(PMSG). In the control group, all the mice inject normal saline in their estrous cycle. Extraet genomic DNA from the mice ovary, the methylation of H19 DMR were analyzed by cloning and sequencing after DNA bifulfite treatment. Many researches reproded that errored expression in H19 gene was related with security in ART.RESULTS: Hypermethylated clones in H19 DMR from ovary in the study group and the control group were of 30.94%±8.72% and 50.31%±7.98%, respectively. Compared with the control Group, loss of methylation was found in the study group(P<0.05).CONCLUTION: This study hint, the loss of methylation in H19 DMR caused by stimulate ovulation.