^(60)Coγ射线诱发小鼠DNA甲基化改变  

DNA methylation changes induced by ^(60)Co γ-ray irradiation

作　　者：黄铖铖[1] 孙秀锦[2] 胡明江[2] 程跃进[2] 古桂雄[1] 崔凤梅[2] 

机构地区：[1]苏州大学附属儿童医院,江苏苏州215003 [2]苏州大学医学部放射医学与公共卫生学院

出　　处：《中国公共卫生》2011年第10期1263-1266,共4页Chinese Journal of Public Health

基　　金：国家自然科学基金(30800922);江苏省高校自然科学基础研究面上项目(08KJD310007)

摘　　要：目的探讨基因组启动子甲基化谱及DNA甲基化酶1(DNMT1)表达量在60Co-γ射线照射小鼠各组织的变化及其意义。方法 SPF级C57BL/6J雄性小鼠12只随机分为对照组和照射组,照射组小鼠接受4Gy60Co-γ射线单次全身照射后,均眼球摘除取血后处死,收集各脏器组织,进行外周血白细胞计数和骨髓嗜多染红细胞微核计数,应用甲基化DNA免疫沉淀-芯片(MeDIP-chip)杂交技术对γ射线照射小鼠肝组织基因组启动子(promoter)CpG岛甲基化改变进行分析,并采用免疫组化(SP)法和蛋白质印记(western blot)法检测小鼠各组织DNMT1的表达情况。结果与对照组比较,照射组小鼠基因组启动子甲基化谱发生了明显改变,照射组1 300个基因的启动子CpG岛发生了新的甲基化,660个基因发生去甲基化;提高筛选标准,最后可得到发生明显甲基化的基因有Trim71、Sema3f、Pcdh8、Sox4、1110034A24Rik、Limk1、Nefl、Xpr1,明显去甲基化的基因有Sfrs18、Dr1、Ankrd42、Nae1、Sfi1、Accn1、Srd5a1、Nsun2、Eif1a、Dusp5;照射组小鼠除肺组织外肝脏、肾、睾丸及脑组织的DNMT1表达量均高于对照组(P<0.05)。结论在电离辐射损伤中基因组启动子甲基化模式发生了改变,DNMT1表达增加可能是导致启动子发生甲基化的原因。Objective To study the change and significance of DNA methylation pattern and DNA methyltransferase（DNMT1） protein in 60Co γ-ray irradiated mice tissues.Methods Twelve SPF C57BL/6J mice were randomly divided intocontrol group and radiation group.The radiation group were exposed to 4Gy-single whole body radiation.All mice were sacrificed 3 days after the radiation.The total number of peripheral white blood cells and the frequencies of micronucleated polychromatic erythocytes（fMNPCE） were measured.Methylated DNA immunoprecipitation-chip（MeDIP-chip） was adopted to investigate the differentially expressed CpG islands methylation profiles in mouse liver genome promoter.The immunohisto-chemical（SP method） and western blot method were used to check the expression of DNMT1 protein in tissues.Results Compared with the control group,the promoter methylation profiles of irradiated mice changed obviously,with 1300 genes methylated and 660 genes demethylated.With the improvement of the screening criteria,the obviously methylated genes were Trim71,Sema3f,Pcdh8,Sox4,1110034A24Rik,Limk1,Nefl,and Xpr1 and the demethylated genes were Sfrs18,Dr1,Ankrd42,Nae1,Sfi1,Accn1,Srd5a1,Nsun2,Eif1a,and Dusp5.Except in the lung,the expression of DNMT1 protein in liver,kidney,testicle,and brain tissues were all increased（P0.05）.Conclusion There are methylation changes of gene promoter in ionizing radiation injury and the increased expression of DNMT1 may be the reason of gene promoter methylation.

关 键 词：60Co-γ射线 DNA甲基化 甲基化DNA免疫沉淀-芯片 DNA甲基化酶 

分 类 号：R818.03[医药卫生—放射医学]