Methylation-sensitive binding of transcription factor YY1 to an insulator sequence within the paternally expressed imprinted gene, Peg3
Methylation-sensitive binding of transcription factor YY1 to an insulator sequence within the paternally expressed imprinted gene, Peg3
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DOI：
10.1093/hmg/ddg028
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发表时间：
2003-02-01
影响因子：
3.5
通讯作者：
Stubbs, L
中科院分区：
文献类型：
--
作者：
Kim, J;Kollhoff, A;Stubbs, L
两个父系表达的小鼠基因Peg3和Usp 29的5 '端与表现出等位基因特异性甲基化的CpG岛联合相关。来自人，小鼠和牛的区域的序列比较揭示了两个进化上保守的序列基序的存在，包括在所有三种哺乳动物中在Peg3的第一内含子内重复多次的序列基序。DNA迁移率变化和染色质免疫沉淀（ChIP）分析清楚地表明，这个基序是一个在体内的GLI型转录因子YY 1的结合位点。YY 1结合位点含有一个CpG二核苷酸，该CpG位点的甲基化消除了YY 1的体外结合活性。PEG 3 YY 1结合位点在体内仅在母体染色体上甲基化，ChIP测定证实YY 1特异性结合该基因的父本等位基因。启动子，增强子和绝缘子测定与删除构建的序列周围的YY 1结合位点表明，该地区的功能作为一个甲基化敏感的绝缘子，可能会影响的印记表达的PEG 3和邻近基因。目前的研究是第一份报告，证明参与YY1甲基化敏感绝缘子活动，并提出了这种高度保守的蛋白质在哺乳动物基因组印迹的潜在作用。
The 5'-ends of two paternally expressed mouse genes, Peg3 and Usp29, are jointly associated with a CpG island that exhibits allele-specific methylation. Sequence comparison of the regions derived from human, mouse and cow revealed the presence of two evolutionarily conserved sequence motifs including one that is repeated multiple times within the first intron of Peg3 in all three mammals. DNA mobility shift and chromatin immunoprecipitation (ChlP) assays clearly demonstrated that this motif is an in vivo binding site for the Gli-type transcription factor YY1. The YY1-binding site contains one CpG dinucleotide, and methylation of this CpG site abolishes the binding activity of YY1 in vitro. The Peg3 YY1-binding sites are methylated only on the maternal chromo some in vivo, and ChlP assays confirmed that YY1 binds specifically to the paternal allele of the gene. Promoter, enhancer and insulator assays with deletion constructs of sequence surrounding the YY1-binding sites indicate that the region functions as a methylation-sensitive insulator that may influence the imprinted expression of Peg3 and neighboring genes. The current study is the first report demonstrating the involvement of YY1 in methylation-sensitive insulator activity and suggests a potential role of this highly conserved protein in mammalian genomic imprinting.