2i 조건에서 Jmjd2c와 Prdm14를 통한 생쥐배아줄기세포의 stemness 유지에 관한 연구

Abstract

Mouse embryonic stem cells (ESCs) are commonly cultured in LIF/serum condition to maintain a naïve state for their self-renewal and pluripotency. The novel culture method using 2 inhibitors (2i), the Mek inhibitor and the Gsk3 inhibitor, with LIF could allow ESCs to go a naïve ground state [1]. However, how 2i maintain the ground state in ESCs remains unexplored. Here I provide the molecular mechanisms by which 2i down-regulate DNA methylation through Jmjd2c and Prdm14. Mek1 directly associates with and phosphorylates Jmjd2c that is a histone H3K9me3- and H3K36me3-specific demethylase. Phosphorylated Jmjd2c by Mek1 undergoes a phosphorylation-dependent ubiquitination pathway. Therefore, Mek1 inhibition causes to increase Jmjd2c protein levels and decrease repressive H3K9me3 levels. Moreover, stabilizing Jmjd2c interacts with Tet1, which is a methyl-cytosine dioxygenase to function as a DNA demethylase, and activates DNA demethylation levels through a Tet1-mediated conversion from 5-mC to 5-hmC. Furthermore, Prdm14 containing a zinc finger SET domain is increased by 2 inhibition. Prdm14 has a methyltransferase activity toward Dnmt3a and Dnmt3b. Methylated Dnmt3a and Dnm3b by Prdm14 are significantly degraded through the methylation-dependent ubiquitination pathway. Thus, decreasing Dnmt3a and Dnmt3b levels by Prdm14 lead to the decrease of DNA methylation passively regardless of Tet1 activity. Collectively, 2i confer ESCs to maintain their ground state pluripotency through Jmjd2c and Prdm14. Jmjd2c and Prdm14 in 2i/LIF condition activates the expression of pluripotent genes through the demethylation of histone and DNA for maintaining the ground state.