Structure of the Dnmt1 Reader Module Complexed with a Unique Two-Mono-Ubiquitin Mark on Histone H3 Reveals the Basis for DNA Methylation Maintenance.

Molecular cell 2017 Oct 19

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The proper location and timing of Dnmt1 activation are essential for DNA methylation maintenance. We demonstrate here that Dnmt1 utilizes two-mono-ubiquitylated histone H3 as a unique ubiquitin mark for its recruitment to and activation at DNA methylation sites. The crystal structure of the replication foci targeting sequence (RFTS) of Dnmt1 in complex with H3-K18Ub/23Ub reveals striking differences to the known ubiquitin-recognition structures. The two ubiquitins are simultaneously bound to the RFTS with a combination of canonical hydrophobic and atypical hydrophilic interactions. The C-lobe of RFTS, together with the K23Ub surface, also recognizes the N-terminal tail of H3. The binding of H3-K18Ub/23Ub results in spatial rearrangement of two lobes in the RFTS, suggesting the opening of its active site. Actually, incubation of Dnmt1 with H3-K18Ub/23Ub increases its catalytic activity in vitro. Our results therefore shed light on the essential role of a unique ubiquitin-binding module in DNA methylation maintenance. Copyright © 2017 Elsevier Inc. All rights reserved.

Citation

Satoshi Ishiyama, Atsuya Nishiyama, Yasushi Saeki, Kei Moritsugu, Daichi Morimoto, Luna Yamaguchi, Naoko Arai, Rumie Matsumura, Toru Kawakami, Yuichi Mishima, Hironobu Hojo, Shintaro Shimamura, Fuyuki Ishikawa, Shoji Tajima, Keiji Tanaka, Mariko Ariyoshi, Masahiro Shirakawa, Mitsunori Ikeguchi, Akinori Kidera, Isao Suetake, Kyohei Arita, Makoto Nakanishi. Structure of the Dnmt1 Reader Module Complexed with a Unique Two-Mono-Ubiquitin Mark on Histone H3 Reveals the Basis for DNA Methylation Maintenance. Molecular cell. 2017 Oct 19;68(2):350-360.e7