中科院广州生物医药健康研究院裴端卿研究组、陈捷凯研究组和上海生化细胞研究所徐国良研究组最近的合作研究结果证实：维生素C调节了TET1在体细胞重编程过程中的功能。相关研究成果于2013年10月27日在线发表于著名学术期刊《自然-遗传学》（Nature Genetics）上。
DNA的甲基化是调控我们人类细胞命运的一个关键开关，近年来发现的Tet蛋白就是参与调控这一开关的一种十分重要的表观遗传修饰酶。多能干细胞相对于体细胞处于DNA低甲基化状态，此前有报道称Tet蛋白有促进体细胞重编程的作用。然而，广州生物院和上海生化细胞所的研究人员采用Tet1基因敲除的小鼠细胞模型进行研究，却发现了Tet1对体细胞重编程的抑制作用。进一步研究发现，通过调节细胞培养条件中的维生素C浓度，可以实现Tet1在促进和抑制角色之间的转换：在存在生理浓度维生素C的情况下，Tet1会显着抑制体细胞重编程过程中一个早期必需的生物学过程——间充质-上皮转化（MET），从而阻碍体细胞重编程；而在维生素C浓度远低于生理浓度的情况下，Tet1的这一作用则会被隐藏起来。
这项发表的最新结果显示：生理浓度的维生素C能够使Tet1从促进体细胞重编程的角色转化为抑制，该发现突破了不少所涉领域的传统认知，提示细胞外环境对细胞命运的调控是至关重要的，也为如何更好地控制细胞命运提供了新的见解
Jiekai Chen,Lin Guo,Lei Zhang, Haoyu Wu,Jiaqi Yang, He Liu, Xiaoshan Wang,Xiao Hu, Tianpeng Gu,Zhiwei Zhou, Jing Liu,Jiadong Liu,Hongling Wu,Shi-Qing Mao, Kunlun Mo, Yingying Li, Keyu Lai,Jing Qi,Hongjie Yao, Guangjin Pan,Guo-Liang Xu & Duanqing Pei
Vitamin C, a micronutrient known for its anti-scurvy activity in humans, promotes the generation of induced pluripotent stem cells (iPSCs)1 through the activity of histone demethylating dioxygenases2, 3. TET hydroxylases are also dioxygenases implicated in active DNA demethylation4, 5, 6, 7, 8. Here we report that TET1 either positively or negatively regulates somatic cell reprogramming depending on the absence or presence of vitamin C. TET1 deficiency enhances reprogramming, and its overexpression impairs reprogramming in the context of vitamin C2, 9 by modulating the obligatory mesenchymal-to-epithelial transition (MET)10, 11. In the absence of vitamin C, TET1 promotes somatic cell reprogramming independent of MET. Consistently, TET1 regulates 5-hydroxymethylcytosine (5hmC) formation at loci critical for MET in a vitamin C–dependent fashion. Our findings suggest that vitamin C has a vital role in determining the biological outcome of TET1 function at the cellular level. Given its benefit to human health, vitamin C should be investigated further for its role in epigenetic regulation.
