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Nature. 2015 Jan 29;517(7536):640-4. doi: 10.1038/nature13899. Epub 2014 Nov 10.

Structural insight into autoinhibition and histone H3-induced activation of DNMT3A.

Author information

  • 11] Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China [2] State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China.
  • 2Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai 200032, China.
  • 3National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
  • 41] High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China [2] National Laboratory for Physical Science at the Microscale, University of Science and Technology of China, Hefei 230026, China [3] School of Life Sciences, University of Science and Technology of China, Hefei 230026, China.
  • 51] National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China [2] University of Chinese Academy of Science, Beijing 100049, China.
  • 6National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Science, Beijing 100101, China.
  • 7State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.

Abstract

DNA methylation is an important epigenetic modification that is essential for various developmental processes through regulating gene expression, genomic imprinting, and epigenetic inheritance. Mammalian genomic DNA methylation is established during embryogenesis by de novo DNA methyltransferases, DNMT3A and DNMT3B, and the methylation patterns vary with developmental stages and cell types. DNA methyltransferase 3-like protein (DNMT3L) is a catalytically inactive paralogue of DNMT3 enzymes, which stimulates the enzymatic activity of Dnmt3a. Recent studies have established a connection between DNA methylation and histone modifications, and revealed a histone-guided mechanism for the establishment of DNA methylation. The ATRX-DNMT3-DNMT3L (ADD) domain of Dnmt3a recognizes unmethylated histone H3 (H3K4me0). The histone H3 tail stimulates the enzymatic activity of Dnmt3a in vitro, whereas the molecular mechanism remains elusive. Here we show that DNMT3A exists in an autoinhibitory form and that the histone H3 tail stimulates its activity in a DNMT3L-independent manner. We determine the crystal structures of DNMT3A-DNMT3L (autoinhibitory form) and DNMT3A-DNMT3L-H3 (active form) complexes at 3.82 and 2.90 Å resolution, respectively. Structural and biochemical analyses indicate that the ADD domain of DNMT3A interacts with and inhibits enzymatic activity of the catalytic domain (CD) through blocking its DNA-binding affinity. Histone H3 (but not H3K4me3) disrupts ADD-CD interaction, induces a large movement of the ADD domain, and thus releases the autoinhibition of DNMT3A. The finding adds another layer of regulation of DNA methylation to ensure that the enzyme is mainly activated at proper targeting loci when unmethylated H3K4 is present, and strongly supports a negative correlation between H3K4me3 and DNA methylation across the mammalian genome. Our study provides a new insight into an unexpected autoinhibition and histone H3-induced activation of the de novo DNA methyltransferase after its initial genomic positioning.

PMID:
25383530
[PubMed - indexed for MEDLINE]
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