Joint Graduate Program of Peking-Tsinghua-NIBS, Tsinghua University, Beijing 100084, China.
Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 19 Xinjiekouwai Avenue, Beijing 100875, China.
Cell Stem Cell. 2022 Jun 2;29(6):948-961.e6. doi: 10.1016/j.stem.2022.05.004.
2-cell-like cells (2CLCs)-which comprise only ∼1% of murine embryonic stem cells (mESCs)-resemble blastomeres of 2-cell-stage embryos and are used to investigate zygotic genome activation (ZGA). Here, we discovered that TRIM66 and DAX1 function together as negative regulators of the 2C-like state in mESCs. Chimeric assays confirmed that mESCs lacking TRIM66 or DAX1 function have bidirectional embryonic and extraembryonic differentiation potential. TRIM66 functions by recruiting the co-repressor DAX1 to the Dux promoter, and TRIM66's repressive effect on Dux is dependent on DAX1. A solved crystal structural shows that TRIM66's PHD finger recognizes H3K4-K9me3, and mutational evidence confirmed that TRIM66's PHD finger is essential for its repression of Dux. Thus, beyond expanding the scope of known 2CLC regulators, our study demonstrates that interventions disrupting TRIM66 or DAX1 function in mESCs yield 2CLCs with expanded bidirectional differentiation potential, opening doors for the practical application of these totipotent-like cells.
2 细胞样细胞（2CLCs）-仅占小鼠胚胎干细胞（mESCs）的约 1％-类似于 2 细胞期胚胎的卵裂球，用于研究合子基因组激活（ZGA）。在这里，我们发现 TRIM66 和 DAX1 共同作为 mESCs 中 2CL 样状态的负调节剂发挥作用。嵌合实验证实，缺乏 TRIM66 或 DAX1 功能的 mESCs 具有双向胚胎和胚胎外分化潜能。TRIM66 通过招募共抑制因子 DAX1 到 Dux 启动子上来发挥作用，并且 TRIM66 对 Dux 的抑制作用依赖于 DAX1。已解决的晶体结构表明，TRIM66 的 PHD 手指识别 H3K4-K9me3，并且突变证据证实 TRIM66 的 PHD 手指对于其对 Dux 的抑制作用至关重要。因此，除了扩大已知 2CLC 调节剂的范围之外，我们的研究表明，干预 mESCs 中的 TRIM66 或 DAX1 功能会产生具有扩展双向分化潜能的 2CLCs，为这些全能样细胞的实际应用开辟了道路。
