S phase-dependent interaction with DNMT1 dictates the role of UHRF1 but not UHRF2 in DNA methylation maintenance

• Published in: Cell research 2011-12, Vol.21 (12), p.1723-1739
• Main Authors: Zhang, Jiqin, Gao, Qinqin, Li, Pishun, Liu, Xiaoli, Jia, Yuanhui, Wu, Weicheng, Li, Jiwen, Dong, Shuo, Koseki, Haruhiko, Wong, Jiemin
• Format: Article
• Language: English
• Subjects: 631/337/100/2285; 631/337/176/1988; 631/45/612/1229; 631/80/641/151; Animals; Biomedical and Life Sciences; Cell Biology; Cells, Cultured; Deoxyribonucleic acid; DNA; DNA (Cytosine-5-)-Methyltransferase 1; DNA (Cytosine-5-)-Methyltransferases - metabolism; DNA Methylation; DNA复制; DNA甲基化; DNA结合活性; Embryonic Stem Cells - metabolism; Heterochromatin - metabolism; Histones - metabolism; Humans; Life Sciences; Mice; Nuclear Proteins - genetics; Nuclear Proteins - metabolism; Original; original-article; Protein Binding; S Phase; Stem cells; Ubiquitin-Protein Ligases - metabolism; 小鼠胚胎干细胞; 相互作用; 组蛋白H3
• ISSN: 1001-0602; 1748-7838
• DOI: 10.1038/cr.2011.176

Recent studies demonstrate that UHRF1 is required for DNA methylation maintenance by targeting DNMT1 to DNA replication foci, presumably through its unique hemi-methylated DNA-binding activity and interaction with DNMT1. UHRF2, another member of the UHRF family proteins, is highly similar to UHRF1 in both sequence and structure, raising questions about its role in DNA methylation. In this study, we demonstrate that, like UHRF1, UHRF2 also binds preferentially to methylated histone H3 lysine 9 （H3K9） through its conserved tudor domain and hemi-methylated DNA through the SET and Ring associated domain. Like UHRFI, UHRF2 is enriched in pericentric heterochromatin. The beterochromatin localization depends to large extent on its methylated H3K9-binding activ- ity and to less extent on its methylated DNA-binding activity. Coimmunoprecipitation experiments demonstrate that both UHRF1 and UHRF2 interact with DNMT1, DNMT3a, DNMT3b and G9a. Despite all these conserved functions, we find that UHRF2 is not able to rescue the DNA methylation defect in Uhrfl null mouse embryonic stem cells. This can be attributed to the inability for UHRF2 to recruit DNMT1 to replication foci during S phase of the cell cycle. Indeed, we find that while UHRF1 interacts with DNMT1 in an S phase-dependent manner in ceils, UHRF2 does not. Thus, our study demonstrates that UHRF2 and UHRF1 are not functionally redundant in DNA methylation mainte- nance and reveals the cell-cycle-dependent interaction between UHRFI and DNMT1 as a key regulatory mechanism targeting DNMT1 for DNA methylation.