Faculty of International Social Sciences

菱田 卓

ヒシダ タカシ  (Takashi Hishida)

基本情報

所属
学習院大学 理学部 生命科学科 教授

J-GLOBAL ID
200901001733863530
researchmap会員ID
1000317623

外部リンク

論文

 27
  • Hayashi M, Keyamura K, Hishida T
    PloS one 13(9) e0204680-e0204680 2018年  査読有り
  • Kenji Keyamura, Kota Arai, Takashi Hishida
    PLoS Genetics 12(7) e1006136 2016年7月1日  査読有り
    Homologous recombination is an evolutionally conserved mechanism that promotes genome stability through the faithful repair of double-strand breaks and single-strand gaps in DNA, and the recovery of stalled or collapsed replication forks. Saccharomyces cerevisiae ATP-dependent DNA helicase Srs2 (a member of the highly conserved UvrD family of helicases) has multiple roles in regulating homologous recombination. A mutation (srs2K41A) resulting in a helicase-dead mutant of Srs2 was found to be lethal in diploid, but not in haploid, cells. In diploid cells, Srs2K41A caused the accumulation of inter-homolog joint molecule intermediates, increased the levels of spontaneous Rad52 foci, and induced gross chromosomal rearrangements. Srs2K41A lethality and accumulation of joint molecules were suppressed by inactivating Rad51 or deleting the Rad51-interaction domain of Srs2, whereas phosphorylation and sumoylation of Srs2 and its interaction with sumoylated proliferating cell nuclear antigen (PCNA) were not required for lethality. The structure-specific complex of crossover junction endonucleases Mus81 and Mms4 was also required for viability of diploid, but not haploid, SRS2 deletion mutants (srs2Δ), and diploid srs2Δ mus81Δ mutants accumulated joint molecule intermediates. Our data suggest that Srs2 and Mus81–Mms4 have critical roles in preventing the formation of (or in resolving) toxic inter-homolog joint molecules, which could otherwise interfere with chromosome segregation and lead to genetic instability.
  • Kenji Keyamura, Chikako Sakaguchi, Yoshino Kubota, Hironori Niki, Takashi Hishida
    JOURNAL OF BIOLOGICAL CHEMISTRY 288(41) 29229-29237 2013年10月  査読有り
    Escherichia coli RecN is an SMC (structural maintenance of chromosomes) family protein that is required for DNA double-strand break (DSB) repair. Previous studies show that GFP-RecN forms nucleoid-associated foci in response to DNA damage, but the mechanism by which RecN is recruited to the nucleoid is unknown. Here, we show that the assembly of GFP-RecN foci on the nucleoid in response to DNA damage involves a functional interaction between RecN and RecA. A novel RecA allele identified in this work, recA(Q300R), is proficient in SOS induction and repair of UV-induced DNA damage, but is deficient in repair of mitomycin C (MMC)-induced DNA damage. Cells carrying recA(Q300R) fail to recruit RecN to DSBs and accumulate fragmented chromosomes after exposure to MMC. The ATPase-deficient RecN(K35A) binds and forms foci at MMC-induced DSBs, but is not released from the MMC-induced DNA lesions, resulting in a defect in homologous recombination-dependent DSB repair. These data suggest that RecN plays a crucial role in homologous recombination-dependent DSB repair and that it is required upstream of RecA-mediated strand exchange.
  • Yuji Masuda, Miki Suzuki, Hidehiko Kawai, Asami Hishiki, Hiroshi Hashimoto, Chikahide Masutani, Takashi Hishida, Fumio Suzuki, Kenji Kamiya
    NUCLEIC ACIDS RESEARCH 40(20) 10394-10407 2012年11月  査読有り
    Post-replication DNA repair in eukaryotes is regulated by ubiquitination of proliferating cell nuclear antigen (PCNA). Monoubiquitination catalyzed by RAD6-RAD18 (an E2-E3 complex) stimulates translesion DNA synthesis, whereas polyubiquitination, promoted by additional factors such as MMS2-UBC13 (a UEV-E2 complex) and HLTF (an E3 ligase), leads to template switching in humans. Here, using an in vitro ubiquitination reaction system reconstituted with purified human proteins, we demonstrated that PCNA is polyubiquitinated predominantly via en bloc transfer of a pre-formed ubiquitin (Ub) chain rather than by extension of the Ub chain on monoubiquitinated PCNA. Our results support a model in which HLTF forms a thiol-linked Ub chain on UBC13 (UBC13 similar to Ub(n)) and then transfers the chain to RAD6 similar to Ub, forming RAD6 similar to Ub(n+1). The resultant Ub chain is subsequently transferred to PCNA by RAD18. Thus, template switching may be promoted under certain circumstances in which both RAD18 and HLTF are coordinately recruited to sites of stalled replication.

共同研究・競争的資金等の研究課題

 13