初情期启动过程中小尾寒羊下丘脑GnRH基因甲基化状态及表达量关系研究

摘要

初情期启动的早晚关系到雌性动物的繁殖性能,GnRH是动物初情期启动过程中的关键基因,其启动子区甲基化状态与GnRH mRNA表达量之间的关系尚不清楚.本研究选择初情期前、临近初情期和初情期雌性小尾寒羊的下丘脑作为样本,利用亚硫酸氢盐测序(BSP)技术和实时荧光定量PCR (qRT-PCR)技术检测了初情期不同阶段小尾寒羊GnRH启动子区的甲基化状态和GnRH mRNA的表达量,并分析二者之间的关系.结果表明:小尾寒羊到达初情期时,GnRH基因启动子区甲基化水平显著降低(P＜0.05),尤其是在启动子区-570位点降低最明显,而随着初情期的启动GnRH mRNA表达量呈上升趋势.结果提示,初情期启动过程中,GnRH mRNA表达量升高可能与下丘脑GnRH基因启动子区特定位点甲基化水平降低存在一定的关系.%Early or late onset of puberty concems the reproductive performance of females.GnRH is the key gene during the onset of puberty,and the relationship between the methylation status of promoter and mRNA expression is unclear.In this paper,the hypothalamus of Small Tail Han Sheep in peri-puberty,pre-puberty and puberty were selected as samples,bisulfite sequencing PCR (BSP) and realtime fluorescence quantitative PCR(qRT-PCR) was used to study the methylation status and GnRH mRNA expression in GnRH promoter region of Small Tail Han Sheep in different stages of puberty.The results showed that with the onset of puberty,the methylation level of GnRH gene promoter significantly decreased,especially in the promoter region-570;meanwhile,with the onset of puberty the expression of GnRH mRNA significantly (P＜0.05)increased.The results suggest that during the onset of puberty,the increased expression of GnRH mRNA may be related to the decrease of methylation level at specific site in the promoter region of GnRH gene in hypothalamic.