Identifying molecular and cellular processes that regulate reprogramming competence of transcription factors broadens our understanding of reprogramming mechanisms. In the present study, by a chemical screen targeting major epigenetic pathways in human reprogramming, we discovered that inhibiting specific epigenetic roadblocks including disruptor of telomeric silencing 1-like (DOT1L)-mediated H3K79/K27 methylation, but also other epigenetic pathways, catalyzed by lysine-specific histone demethylase 1A, DNA methyltransferases and histone deacetylases, allows induced pluripotent stem cell generation with almost all OCT factors. We found that simultaneous inhibition of these pathways not only dramatically enhances reprogramming competence of most OCT factors, but in fact enables dismantling of species-dependent reprogramming competence of OCT6, NR5A1, NR5A2, TET1 and GATA3. Harnessing these induced permissive epigenetic states, we performed an additional screen with 98 candidate genes. Thereby, we identified 25 transcriptional regulators (OTX2, SIX3, and so on) that can functionally replace OCT4 in inducing pluripotency. Our findings provide a conceptual framework for understanding how transcription factors elicit reprogramming in dependency of the donor cell epigenome that differs across species.

鉴定调节转录因子重编程能力的分子和细胞过程，拓宽了我们对重编程机制的理解。在本研究中，通过针对人类重编程中主要表观遗传途径的化学筛选，我们发现抑制特定表观遗传障碍，包括端粒沉默1样（DOT1L）介导的H3K79 / K27甲基化的破坏者，还抑制了其他表观遗传途径赖氨酸特异的组蛋白脱甲基酶1A，DNA甲基转移酶和组蛋白脱乙酰基酶可以诱导几乎所有OCT因子诱导的多能干细胞生成。我们发现，同时抑制这些途径不仅可以大大增强大多数OCT因子的重编程能力，而且实际上可以消除OCT6，NR5A1，NR5A2，TET1和GATA3。利用这些诱导的允许表观遗传状态，我们对98个候选基因进行了额外的筛选。因此，我们确定了25个转录调节因子（OTX2，SIX3等），它们可以在功能上替代OCT4，从而诱导多能性。我们的发现为理解转录因子如何根据物种间不同的供体细胞表观基因组的依赖性引发重编程提供了一个概念框架。