Genomic imprinting gives rise to parent-of-origin dependent allelic gene expression. Most imprinted genes cluster in domains where differentially methylated regions (DMRs)-carrying CpG methylation on one parental allele-regulate their activity. Several imprinted DMRs bind CTCF on the non-methylated allele. CTCF structures TADs ('Topologically Associating Domains'), which are structural units of transcriptional regulation. Recent investigations show that imprinted domains are embedded within TADs that are similar on both parental chromosomes. Within these TADs, however, allelic subdomains are structured by combinations of mono-allelic and bi-allelic CTCF binding that guide imprinted expression. This emerging view indicates that imprinted chromosomal domains should be considered at the overarching TAD level, and questions how CTCF integrates with other regulatory proteins and lncRNAs to achieve imprinted transcriptional programs.

中文翻译：

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基因组印迹中的差异3D染色质组织和基因活性。

基因组印记引起起源于父母的等位基因表达。大多数印迹基因聚集在一个亲本等位基因上携带CpG甲基化的差异甲基化区域（DMR）调节其活性的域中。几个印迹的DMR在未甲基化的等位基因上结合CTCF。CTCF构成TAD（“拓扑关联域”），后者是转录调控的结构单元。最近的研究表明，印迹域嵌入在两个亲本染色体上都相似的TAD中。但是，在这些TAD中，等位基因亚域是由单等位基因和双等位基因CTCF结合的组合构成的，可指导印迹表达。这种新兴观点表明，应在总体TAD级别上考虑印迹的染色体结构域，