新疆巴什拜羊肌肉生长抑制素基因DNA甲基化与mRNA表达量分析

为了探究肌肉生长抑制素（myostatin，MSTN）基因在肌肉和脂肪中的DNA甲基化模式及mRNA表达水平，试验以5月龄巴什拜羊羔羊为研究对象，采用亚硫酸氢盐测序法（bisulfite sequencing PCR，BSP）检测MSTN基因启动子区和第1外显子甲基化模式，并通过实时荧光定量PCR检测MSTN基因在巴什拜羊股二头肌、股三头肌、半腱肌、半膜肌、背最长肌和尾脂中的mRNA表达水平。结果显示，肌肉组织甲基化概率高于脂肪组织，其中，股二头肌、股三头肌、半腱肌、半膜肌、背最长肌和尾脂的甲基化概率分别为74.2%、74.2%、83.2%、83.7%、82.1%和25.3%，MSTN基因在股二头肌、股三头肌、半腱肌、半膜肌、背最长肌中的表达水平显著低于尾脂（P < 0.05），股二头肌、股三头肌、半腱肌、半膜肌和背最长肌之间差异不显著（P > 0.05），巴什拜羊肌肉和脂肪MSTN基因DNA甲基化水平与MSTN基因表达量呈显著负相关（r=－0.886，P < 0.05）。

Analysis of DNA Methylation and mRNA Expression Level of MSTN Gene in Xinjiang Bashiby Sheep

In order to investigate DNA methylation and expression levels of myostatin (MSTN) gene in mscule and fat, 5 months of age of Bashiby sheep were selected, the promoter region and exon 1 methylation levels of MSTN gene was analyzed using bisulfite sequencing PCR (BSP). Real-time PCR was used to detect the expression level of MSTN gene in biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle and tail fat of Bashiby sheep. The results showed that the methylation probability of muscle was higher than fat, the methylation probability of biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle and tail fat were 74.2%, 74.2%, 83.2%, 83.7%, 82.1% and 25.3%, respectively. The expression levels of MSTN gene in biceps femoris, femoral triceps, semitendinosus, semimembranosus, longissimus dorsi muscle were significantly lower than tail fat in Bashiby sheep (P < 0.05), but there were no significant difference among biceps femoris, femoral triceps, semitendinosus, semimembranosus and longissimus dorsi muscle (P > 0.05).The DNA methylation was negatively correlated with the expression levels in muscle and fat of Bashiby sheep (r=-0.886, P < 0.05).