Chang Gang, Gao Shuai, Hou Xinfeng, Xu Zijian, Liu Yanfeng, Kang Lan, Tao Yu, Liu Wenqiang, Huang Bo, Kou Xiaochen, Chen Jiayu, An Lei, Miao Kai, Di Keqian, Wang Zhilong, Tan Kun, Cheng Tao, Cai Tao, Gao Shaorong, Tian Jianhui
1] Ministry of Agriculture Key Laboratory of Animal Genetics, Breeding and Reproduction, National Engineering Laboratory for Animal Breeding, College of Animal Sciences and Technology, China Agricultural University, 2 Yuanmingyuan West Road, Haidian District, Beijing 100193, China [2] National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.
National Institute of Biological Sciences, 7 Science Park Road, Zhongguancun Life Science Park, Beijing 102206, China.
Cell Res. 2014 Mar;24(3):293-306. doi: 10.1038/cr.2013.173. Epub 2013 Dec 31.
It remains controversial whether the abnormal epigenetic modifications accumulated in the induced pluripotent stem cells (iPSCs) can ultimately affect iPSC pluripotency. To probe this question, iPSC lines with the same genetic background and proviral integration sites were established, and the pluripotency state of each iPSC line was characterized using tetraploid (4N) complementation assay. Subsequently, gene expression and global epigenetic modifications of "4N-ON" and the corresponding "4N-OFF" iPSC lines were compared through deep sequencing analyses of mRNA expression, small RNA profile, histone modifications (H3K27me3, H3K4me3, and H3K4me2), and DNA methylation. We found that methylation of an imprinted gene, Zrsr1, was consistently disrupted in the iPSC lines with reduced pluripotency. Furthermore, the disrupted methylation could not be rescued by improving culture conditions or subcloning of iPSCs. Moreover, the relationship between hypomethylation of Zrsr1 and pluripotency state of iPSCs was further validated in independent iPSC lines derived from other reprogramming systems.
诱导多能干细胞（iPSC）中积累的异常表观遗传修饰是否最终会影响iPSC的多能性仍存在争议。为探究这个问题，建立了具有相同遗传背景和原病毒整合位点的iPSC系，并使用四倍体（4N）互补试验对每个iPSC系的多能性状态进行了表征。随后，通过对mRNA表达、小RNA谱、组蛋白修饰（H3K27me3、H3K4me3和H3K4me2）以及DNA甲基化的深度测序分析，比较了“4N-ON”和相应的“4N-OFF”iPSC系的基因表达和整体表观遗传修饰。我们发现，在多能性降低的iPSC系中，印记基因Zrsr1的甲基化始终受到破坏。此外，通过改善培养条件或iPSC的亚克隆无法挽救被破坏的甲基化。此外，在源自其他重编程系统的独立iPSC系中进一步验证了Zrsr1的低甲基化与iPSC多能性状态之间的关系。
