Chen Bo, Jia Mingkang, Zhao Gan, Liu Yumin, Song Yihong, Sun Mengjie, Chi Wangfei, Wang Xiangyang, Jiang Qing, Xin Guangwei, Zhang Chuanmao
The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China.
The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, College of Life Sciences, Peking University, Beijing, China; The Academy for Cell and Life Health, Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.
J Biol Chem. 2024 Dec;300(12):107958. doi: 10.1016/j.jbc.2024.107958. Epub 2024 Nov 5.
Mouse embryonic stem cells (mESCs) exist in two distinct pluripotent states: the naive and the primed. Mainly by inducing differentiation of mESCs in vitro, conducting RNA sequencing analyses, and specifying expression of the regulatory genes, we explored the regulatory mechanisms underlying the transition between the naive and primed states. We found that, under the defined differentiation-inducing conditions, the naive state of mESCs shifted to the primed state within 2 days of differentiation induction, during which the cell cycle- and differentiation-related proteins changes significantly. Specifically, we uncovered that the expression of STAG2, a subunit of the Cohesin complex, was upregulated. We further revealed that knockout of STAG2 resulted in upregulation of the naive gene sets and downregulation of the primed gene sets, indicating importance of STAG2 in regulating the naive-primed transition. More importantly, STAG2 knockout led to a reduction in number of the bivalent genes, a decrease in Lin28a transcription, and a reduced cytoplasmic localization of Lin28a. Overexpressing Lin28a or a Lin28a variant lacking the nucleolar localization signal (Lin28aΔNoLS) in STAG2 knockout cells rescued the downregulation of the primed marker genes Dnmt3a/3b. Collectively, we conclude that STAG2 facilitates the naive-primed transition of mESCs by activating Lin28a transcription and that this work may offer a new insight into the regulation of pluripotency in mESCs.
小鼠胚胎干细胞（mESCs）存在两种不同的多能状态：原始态和始发态。主要通过在体外诱导mESCs分化、进行RNA测序分析以及确定调控基因的表达，我们探索了原始态和始发态之间转变的调控机制。我们发现，在确定的诱导分化条件下，mESCs的原始态在分化诱导的2天内转变为始发态，在此期间细胞周期和分化相关蛋白发生显著变化。具体而言，我们发现黏连蛋白复合体的一个亚基STAG2的表达上调。我们进一步揭示，敲除STAG2导致原始基因集上调和始发基因集下调，表明STAG2在调节原始态-始发态转变中具有重要作用。更重要的是，STAG2敲除导致二价基因数量减少、Lin28a转录减少以及Lin28a的细胞质定位减少。在STAG2敲除细胞中过表达Lin28a或缺乏核仁定位信号的Lin28a变体（Lin28aΔNoLS）挽救了始发标记基因Dnmt3a/3b的下调。我们共同得出结论，STAG2通过激活Lin28a转录促进mESCs的原始态-始发态转变，并且这项工作可能为mESCs多能性的调控提供新的见解。
