Takahashi Yuta, Wu Jun, Suzuki Keiichiro, Martinez-Redondo Paloma, Li Mo, Liao Hsin-Kai, Wu Min-Zu, Hernández-Benítez Reyna, Hishida Tomoaki, Shokhirev Maxim Nikolaievich, Esteban Concepcion Rodriguez, Sancho-Martinez Ignacio, Belmonte Juan Carlos Izpisua
Gene Expression Laboratory, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577, Japan.
Science. 2017 May 5;356(6337):503-508. doi: 10.1126/science.aag3260.
CpG islands (CGIs) are primarily promoter-associated genomic regions and are mostly unmethylated within highly methylated mammalian genomes. The mechanisms by which CGIs are protected from de novo methylation remain elusive. Here we show that insertion of CpG-free DNA into targeted CGIs induces de novo methylation of the entire CGI in human pluripotent stem cells (PSCs). The methylation status is stably maintained even after CpG-free DNA removal, extensive passaging, and differentiation. By targeting the DNA mismatch repair gene CGI, we could generate a PSC model of a cancer-related epimutation. Furthermore, we successfully corrected aberrant imprinting in induced PSCs derived from an Angelman syndrome patient. Our results provide insights into how CpG-free DNA induces de novo CGI methylation and broaden the application of targeted epigenome editing for a better understanding of human development and disease.
CpG岛（CGIs）主要是与启动子相关的基因组区域，在高度甲基化的哺乳动物基因组中大多处于未甲基化状态。CGIs免受从头甲基化影响的机制仍然不清楚。在这里，我们表明，将无CpG的DNA插入靶向的CGIs会在人类多能干细胞（PSCs）中诱导整个CGI的从头甲基化。即使在去除无CpG的DNA、广泛传代和分化后，甲基化状态仍能稳定维持。通过靶向DNA错配修复基因CGI，我们可以生成一种癌症相关表观突变的PSC模型。此外，我们成功纠正了来自天使综合征患者的诱导PSCs中的异常印记。我们的结果为无CpG的DNA如何诱导CGI从头甲基化提供了见解，并拓宽了靶向表观基因组编辑的应用，以更好地理解人类发育和疾病。
