Updated on 2023/09/11

写真a

 
MASUDA Yuji
 
Organization
Research Institute of Environmental Medicine Division of Stress Adaptation and Protection Associate professor
Graduate School
Graduate School of Medicine
Title
Associate professor
Contact information
メールアドレス

Degree 1

  1. 博士(農学) ( 1995.3   東京大学 ) 

Research Areas 1

  1. Others / Others  / 生化学

Research History 7

  1. 名古屋大学大学院医学研究科総合医学専攻・准教授           名古屋大学環境医学研究所・准教授

    2013.5

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    Country:Japan

  2. 名古屋大学環境医学研究所・准教授

    2011.10 - 2013.4

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    Country:Japan

  3. 広島大学原爆放射線医科学研究所・助教

    2007.4 - 2011.9

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    Country:Japan

  4. 広島大学原爆放射線医科学研究所・助手

    2002.4 - 2007.3

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    Country:Japan

  5. 広島大学原爆放射能医学研究所・助手

    1998.7 - 2002.3

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    Country:Japan

  6. ハーバード大学公衆衛生大学院・博士研究員

    1996.9 - 1998.6

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    Country:United States

  7. 奈良先端科学技術大学院大学バイオサイエンス研究科・教務職員

    1995.4 - 1996.8

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    Country:Japan

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Education 2

  1. The University of Tokyo

    - 1995.3

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    Country: Japan

  2. Saitama University   Faculty of Science

    1986.4 - 1990.3

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    Country: Japan

Professional Memberships 5

  1. 日本癌学会

  2. 日本放射線影響学会

  3. 日本分子生物学会

  4. 日本遺伝学会

  5. 環境変異原学会

Awards 4

  1. 日本遺伝学会第88回大会 ベストペーパー賞

    2017.3   日本遺伝学会  

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    Award type:Award from Japanese society, conference, symposium, etc.  Country:Japan

  2. 日本遺伝学会第83回大会 ベストペーパー賞

    2012.3   日本遺伝学会  

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    Country:Japan

  3. 日本遺伝学会第82回大会 ベストペーパー賞

    2011.3   日本遺伝学会  

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    Country:Japan

  4. 日本遺伝学会奨励賞

    2008   日本遺伝学会  

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    Country:Japan

 

Papers 44

  1. Novel mechanisms for the removal of strong replication-blocking HMCES- and thiazolidine-DNA adducts in humans.

    Sugimoto Y, Masuda Y, Iwai S, Miyake Y, Kanao R, Masutani C

    Nucleic acids research   Vol. 51 ( 10 ) page: 4959 - 4981   2023.6

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    Language:English  

    DOI: 10.1093/nar/gkad246

    PubMed

  2. Stepwise multipolyubiquitination of p53 by the E6AP-E6 ubiquitin ligase complex. Reviewed

    Masuda Y, Saeki Y, Arai N, Kawai H, Kukimoto I, Tanaka K, Masutani C

    The Journal of biological chemistry   Vol. 294 ( 41 ) page: 14860-14875   2019.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1074/jbc.RA119.008374

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  3. Spatiotemporal regulation of PCNA ubiquitination in damage tolerance pathways Invited Reviewed

    Masuda Yuji, Masutani Chikahide

    CRITICAL REVIEWS IN BIOCHEMISTRY AND MOLECULAR BIOLOGY   Vol. 54 ( 5 ) page: 418 - 442   2019.9

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1080/10409238.2019.1687420

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  4. Preferential digestion of PCNA-ubiquitin and p53-ubiquitin linkages by USP7 to remove polyubiquitin chains from substrates Reviewed

    Masuda Yuji, Kanao Rie, Kawai Hidehiko, Kukimoto Iwao, Masutani Chikahide

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 294 ( 11 ) page: 4177 - 4187   2019.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1074/jbc.RA118.005167

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  5. Regulation of HLTF-mediated PCNA polyubiquitination by RFC and PCNA monoubiquitination levels determines choice of damage tolerance pathway. Reviewed

    Masuda Y, Mitsuyuki S, Kanao R, Hishiki A, Hashimoto H, Masutani C

    Nucleic acids research   Vol. 46 ( 21 ) page: 11340 - 11356   2018.11

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/nar/gky943

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  6. Overexpression of Rev1 promotes the development of carcinogen-induced intestinal adenomas via accumulation of point mutation and suppression of apoptosis proportionally to the Rev1 expression level. Reviewed

    Sasatani M, Xi Y, Kajimura J, Kawamura T, Piao J, Masuda Y, Honda H, Kubo K, Mikamoto T, Watanabe H, Xu Y, Kawai H, Shimura T, Noda A, Hamasaki K, Kusunoki Y, Zaharieva EK, Kamiya K*

    Carcinogenesis. 2017 May 1;38(5):570-578. doi: 10.1093/carcin/bgw208.   Vol. 38 ( 5 ) page: 570-578   2017.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: doi: 10.1093/carcin/bgw208

  7. USP7 Is a Suppressor of PCNA Ubiquitination and Oxidative-Stress-Induced Mutagenesis in Human Cells. Reviewed

    Kashiwaba S#, Kanao R#, Masuda Y#, Kusumoto-Matsuo R, Hanaoka F, Masutani C* (#: co-first author)

    Cell Rep.   Vol. 13 ( 10 ) page: 2072-2080   2015.12

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.celrep.2015.11.014

  8. Short CCG repeat in huntingtin gene is an obstacle for replicative DNA polymerases, potentially hampering progression of replication fork. Reviewed

    Le HP, Masuda Y, Tsurimoto T, Maki S, Katayama T, Furukohri A*, Maki H

    Genes Cells   Vol. 20 ( 10 ) page: 817 - 833   2015.10

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1111/gtc.12275

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  9. Different types of interaction between PCNA and PIP boxes contribute to distinct cellular functions of Y-family DNA polymerases Reviewed

    Masuda Y#, Kanao R#, Kaji K, Ohmori H, Hanaoka F, Masutani C* (#: co-first author)

    Nucleic Acids Res.   Vol. 43 ( 16 ) page: 7898-7910   2015.9

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 43(16):7898-910

  10. Repair synthesis step involving ERCC1-XPF participates in DNA repair of the Top1-DNA damage complex Reviewed

    Takahata C, Masuda Y, Takedachi A, Tanaka K, Iwai S and Kuraoka I*

    Carcinogenesis   Vol. 36 ( 8 ) page: 841 - 851   2015.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/carcin/bgv078

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  11. Relevance of Simultaneous Mono-Ubiquitinations of Multiple Units of PCNA Homo-Trimers in DNA Damage Tolerance Reviewed

    Kanao R, Masuda Y, Deguchi S, Yumoto-Sugimoto M, Hanaoka F, Masutani C*

    PLoS One. 9:e104279. 2014.   Vol. 10 ( 2 ) page: e0118775   2015.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.1371/journal.pone.0118775

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  12. A Novel ATM/TP53/p21-Mediated Checkpoint Only Activated by Chronic γ-Irradiation. Reviewed

    Cao L, Kawai H*, Sasatani M, Iizuka D, Masuda Y, Inaba T, Suzuki K, Ootsuyama A, Umata T, Kamiya K, Suzuki F.

    PLoS One. 9:e104279. 2014.   Vol. 9   page: e104279   2014.8

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI: 10.1371/journal.pone.0104279

  13. Guanine-5-carboxylcytosine base pairs mimic mismatches during DNA replication. Reviewed

    Shibutani T, Ito S, Toda M, Kanao R, Collins LB, Shibata M, Urabe M, Koseki H, Masuda Y, Swenberg JA, Masutani C, Hanaoka F, Iwai S, Kuraoka I.*

    Sci Rep.   Vol. 4   page: 5220   2014.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI: 10.1038/srep05220

  14. A novel interplay between the Fanconi anemia core complex and ATR-ATRIP kinase during DNA cross-link repair. Reviewed

      Vol. 41 ( 14 ) page: 6930-6941   2013.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/nar/gkt467

  15. Strand breakage of (6–4) photoproduct-containing DNA at neutral pH and its repair by the ERCC1–XPF protein complex. Reviewed

      Vol. 11 ( 21 ) page: 3526-3534   2013.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1039/c3ob00012e

  16. En bloc transfer of polyubiquitin chains to PCNA in vitro is mediated by two different human E2-E3 pairs. Reviewed

    Masuda Y*, Suzuki M, Kawai H, Hishiki A, Hashimoto H, Masutani C, Hishida T, Suzuki F, Kamiya K*.

    Nucleic Acids Res.     2012.8

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1093/nar/gks763

  17. In Vitro Studies of Exchanges between Replicative and Translesion DNA Polymerases in the Eukaryotic Post-replication Repair Pathway Invited Reviewed

    Masuda Y*

    Genes and Environment   Vol. 34 ( 2 ) page: 70-76   2012.5

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3123/jemsge.34.70

  18. Molecular nature of radiation injury and DNA repair disorders associated with radiosensitivity. Invited Reviewed

    Masuda Y, Kamiya K*

    International Journal of Hematology   Vol. 95 ( 3 ) page: 239-245   2012.3

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: DOI 10.1007/s12185-012-1008-y

  19. Asymmetric nature of two subunits of RAD18, a RING-type ubiquitin ligase E3, in the human RAD6A-RAD18 ternary complex Reviewed

    Masuda Y*, Suzuki M, Kawai H, Suzuki F, Kamiya K.

    Nucleic Acids Research   Vol. 40 ( 3 ) page: 1065-1076   2012.2

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    RAD18, a RING-type ubiquitin ligase (E3) that plays an essential role in post-replication repair, possesses distinct domains named RING, UBZ, SAP and the RAD6-binding domain (R6BD) and forms a dimer. RAD6, an ubiquitin-conjugating enzyme (E2), stably associates with R6BD in the C-terminal portion. In this study, we established a method to distinguish between the two subunits of RAD18 by introduction of different tags, and analyzed mutant complexes. Our results, surprisingly, demonstrate that RAD6A and RAD18 form a ternary complex, RAD6A-(RAD18)(2) and the presence of only one R6BD in the two RAD18 subunits is sufficient for ternary complex formation and the ligase activity. Interestingly, ligase activity of a mutant dimer lacking both R6BDs is not restored even with large amounts of RAD6A added in solution, suggesting a requirement for precise juxtaposition via interaction with R6BD. We further show that mutations in both subunits of either RING or SAP, but not UBZ, strongly reduce ligase activity, although inactivation in only one of two subunits is without effect. These results suggest an asymmetric nature of the two RAD18 subunits in the complex.

  20. The Rev1 translesion synthesis polymerase has multiple distinct DNA binding modes

    de Groote Frederik H., Jansen Jacob G., Masuda Yuji, Shah Dipen M., Kamiya Kenji, de Wind Niels, Siegal Gregg

    DNA REPAIR   Vol. 10 ( 9 ) page: 915 - 925   2011.9

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  21. Regulation of DNA Polymerase POLD4 Influences Genomic Instability in Lung Cancer

    Huang Qin Miao, Tomida Shuta, Masuda Yuji, Arima Chinatsu, Cao Ke, Kasahara Taka-Aki, Osada Hirotaka, Yatabe Yasushi, Akashi Tomohiro, Kamiya Kenji, Takahashi Takashi, Suzuki Motoshi

    CANCER RESEARCH   Vol. 70 ( 21 ) page: 8407 - 8416   2010.11

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  22. DNA Replication-Coupled PCNA Mono-Ubiquitination and Polymerase Switching in a Human In Vitro System

    Masuda Yuji, Piao Jinlian, Kamiya Kenji

    JOURNAL OF MOLECULAR BIOLOGY   Vol. 396 ( 3 ) page: 487 - 500   2010.2

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  23. Specific amino acid residues are involved in substrate discrimination and template binding of human REV1 protein

    Piao Jinlian, Masuda Yuji, Kamiya Kenji

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   Vol. 392 ( 2 ) page: 140 - 144   2010.2

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  24. Roles of POLD4, smallest subunit of DNA polymerase delta, in nuclear structures and genomic stability of human cells

    Huang Qin Miao, Akashi Tomohiro, Masuda Yuji, Kamiya Kenji, Takahashi Takashi, Suzuki Motoshi

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   Vol. 391 ( 1 ) page: 542 - 546   2010.1

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  25. Translesional DNA Synthesis through a C8-Guanyl Adduct of 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in Vitro REV1 INSERTS dC OPPOSITE THE LESION, AND DNA POLYMERASE kappa POTENTIALLY CATALYZES EXTENSION REACTION FROM THE 3 '-dC TERMINUS

    Fukuda Hirokazu, Takamura-Enya Takeji, Masuda Yuji, Nohmi Takehiko, Seki Chiho, Kamiya Kenji, Sugimura Takashi, Masutani Chikahide, Hanaoka Fumio, Nakagama Hitoshi

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 284 ( 38 ) page: 25585 - 25592   2009.9

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    DOI: 10.1074/jbc.M109.037259

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  26. Biochemical analysis of human PIF1 helicase and functions of its N-terminal domain

    Gu Yongqing, Masuda Yuji, Kamiya Kenji

    NUCLEIC ACIDS RESEARCH   Vol. 36 ( 19 ) page: 6295 - 6308   2008.11

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  27. [Induced mutagenesis and translesion DNA synthesis--structure and function of REV1].

    Masuda Y, Kamiya K

    Seikagaku. The Journal of Japanese Biochemical Society   Vol. 80 ( 9 ) page: 843 - 6   2008.9

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  28. DNA damage-induced ubiquitylation of RFC2 subunit of replication factor C complex.

    Tomida J, Masuda Y, Hiroaki H, Ishikawa T, Song I, Tsurimoto T, Tateishi S, Shiomi T, Kamei Y, Kim J, Kamiya K, Vaziri C, Ohmori H, Todo T

    The Journal of biological chemistry   Vol. 283 ( 14 ) page: 9071 - 9   2008.4

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  29. Structural studies of human PCNA mutant, REV6-1

    Hishiki Asami, Hashimoto Hiroshi, Masuda Yuji, Saijo Shinya, Serizawa Aya, Kamiya Kenji, Ohmori Haruo, Shimizu Toshiyuki, Sato Mamoru

    ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES   Vol. 64   page: C378 - C378   2008

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  30. Dynamics of human replication factors in the elongation phase of DNA replication

    Masuda Yuji, Suzuki Miki, Piao Jinlian, Gu Yongqing, Tsurimoto Toshiki, Kamiya Kenji

    NUCLEIC ACIDS RESEARCH   Vol. 35 ( 20 ) page: 6904 - 6916   2007.11

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  31. Role of single-stranded DNA in targeting REV1 to primer termini

    Masuda Yuji, Kamiya Kenji

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 281 ( 34 ) page: 24314 - 24321   2006.8

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  32. The first US-Japan meeting on error-prone DNA synthesis, Maui, Hawaii, December 20-21, 2004.

    Kamath-Loeb AS, Loeb LA, Masuda Y, Hanaoka F

    DNA repair   Vol. 4 ( 6 ) page: 740 - 7   2005.6

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    DOI: 10.1016/j.dnarep.2005.02.003

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  33. Mouse Rev1 protein interacts with multiple DNA polymerases involved in translesion DNA synthesis.

    Guo C, Fischhaber PL, Luk-Paszyc MJ, Masuda Y, Zhou J, Kamiya K, Kisker C, Friedberg EC

    The EMBO journal   Vol. 22 ( 24 ) page: 6621 - 30   2003.12

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    DOI: 10.1093/emboj/cdg626

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  34. Structure and enzymatic properties of a stable complex of the human REV1 and REV7 proteins

    Masuda Y, Ohmae M, Masuda K, Kamiya K

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 278 ( 14 ) page: 12356 - 12360   2003.4

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    DOI: 10.1074/jbc.M211765200

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  35. Biochemical properties of the human REV1 protein.

    Masuda Y, Kamiya K

    FEBS letters   Vol. 520 ( 1-3 ) page: 88 - 92   2002.6

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    DOI: 10.1016/s0014-5793(02)02773-4

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  36. Hyper-processive and slower DNA chain elongation catalysed by DNA polymerase III holoenzyme purified from the dnaE173 mutator mutant of Escherichia coli.

    Sugaya Y, Ihara K, Masuda Y, Ohtsubo E, Maki H

    Genes to cells : devoted to molecular & cellular mechanisms   Vol. 7 ( 4 ) page: 385 - 99   2002.4

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    DOI: 10.1046/j.1365-2443.2002.00527.x

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  37. Mechanisms of dCMP transferase reactions catalyzed by mouse Rev1 protein

    Masuda Y, Takahashi M, Fukuda S, Sumii M, Kamiya K

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 277 ( 4 ) page: 3040 - 3046   2002.1

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  38. Deoxycytidyl transferase activity of the human REV1 protein is closely associated with the conserved polymerase domain

    Masuda Y, Takahashi M, Tsunekuni N, Minami T, Sumii M, Miyagawa K, Kamiya K

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 276 ( 18 ) page: 15051 - 15058   2001.5

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  39. Murine and human SDF2L1 is an endoplasmic reticulum stress-inducible gene and encodes a new member of the Pmt/rt protein family

    Fukuda S, Sumii M, Masuda Y, Takahashi M, Koike N, Teishima J, Yasumoto H, Itamoto T, Asahara T, Dohi K, Kamiya K

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   Vol. 280 ( 1 ) page: 407 - 414   2001.1

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  40. Single-turnover analysis of mutant human apurinic/apyrimidinic endonuclease

    Lucas JA, Masuda Y, Bennett RAO, Strauss NS, Strauss PR

    BIOCHEMISTRY   Vol. 38 ( 16 ) page: 4958 - 4964   1999.4

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  41. Roles of AP endonucleases in repair and genetic stability

    Demple B, Bailey E, Bennett RAO, Masuda Y, Wong D, Xu YJ

    ADVANCES IN DNA DAMAGE AND REPAIR   Vol. 302   page: 59 - 66   1999

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  42. Rapid dissociation of human apurinic endonuclease (Ape1) from incised DNA induced by magnesium

    Masuda Y, Bennett RAO, Demple B

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 273 ( 46 ) page: 30360 - 30365   1998.11

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  43. Dynamics of the interaction of human apurinic endonuclease (Ape1) with its substrate and product

    Masuda Y, Bennett RAO, Demple B

    JOURNAL OF BIOLOGICAL CHEMISTRY   Vol. 273 ( 46 ) page: 30352 - 30359   1998.11

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  44. Isolation of temperature-sensitive aminoacyl-tRNA synthetase mutants from an Escherichia coli strain harboring the pemK plasmid.

    Masuda Y, Tsuchimoto S, Nishimura A, Ohtsubo E

    Molecular & general genetics : MGG   Vol. 238 ( 1-2 ) page: 169 - 76   1993.4

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    DOI: 10.1007/BF00279544

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Research Project for Joint Research, Competitive Funding, etc. 2

  1. チェックポイント機能を欠如したがん細胞特異的に化学療法の効果を増感させる薬剤の開発

    2011.12 - 2012.7

    研究成果最適展開支援プログラムA-STEPフィージビリティスタディステージ 探索タイプ 

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    Grant type:Competitive

  2. 哺乳類での突然変異誘発の分子機構の解明

    2003.4 - 2007.3

    特色ある大学教育支援プログラム 

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    Grant type:Competitive

KAKENHI (Grants-in-Aid for Scientific Research) 21

  1. 脱塩基部位-タンパク質クロスリンクにより開始する新規DNA損傷トレランス経路

    Grant number:23K11418  2023.4 - 2026.3

    科学研究費助成事業  基盤研究(C)

    増田 雄司

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    Authorship:Principal investigator 

    Grant amount:\4680000 ( Direct Cost: \3600000 、 Indirect Cost:\1080000 )

    DNA損傷はがん化や老化プロセスを促進する主要な原因の一つであり、内因性/外因性のDNA損傷に対する細胞応答機構の重要性が指摘されている。脱塩基損傷は主要な内因性のDNA損傷であり、動物組織の細胞では非常に多くの脱塩基損傷が定常的に存在している。脱塩基損傷は内/外因性の酸化反応に起因するだけではなく、生命現象さまざまな局面(APOBECによる副反応、免疫細胞での体細胞超突然変異、受精卵の初期化過程)で生じ、ある局面では突然変異を誘発する一方、別の局面では突然変異を抑制する未解明の制御機構の存在が示唆される。本研究では脱塩基損傷から細胞を保護するために必要な未解明の制御メカニズムを明らかにする。

  2. 誘発変異頻度を規定する損傷トレランス経路の時空間的制御の分子基盤の確立

    Grant number:18H03371  2018.4 - 2022.3

    科学研究費補助金  基盤研究(B)

    増田雄司

  3. Multiple mechanisms of post-replication repair pathway choice by deubiquitinases for ubiquitinated PCNA

    Grant number:16K12594  2016.4 - 2018.3

    MASUDA Yuji

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    Grant amount:\3770000 ( Direct Cost: \2900000 、 Indirect Cost:\870000 )

    The DNA damage tolerance pathways as the post-replication repair are regulated by ubiquitination of proliferating cell nuclear antigen (PCNA). Since mono- and poly-ubiquitination of PCNA stimulates the error-prone pathway, translesion DNA synthesis (TLS), and the error-free, in principle, pathway, template switch (TS), respectively. However, in humans, the regulatory mechanism is obscure because poly-ubiquitinated PCNA is only slightly detectable. In this study, we identified deubiquitinases for ubiquitinated PCNA and analyzed their functions in the damage tolerance pathways.

  4. Biochemical study of damage tolerance pathways to control the induced mutagenesis

    Grant number:15H02818  2015.4 - 2019.3

    Masuda Yuji

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    Grant amount:\12610000 ( Direct Cost: \9700000 、 Indirect Cost:\2910000 )

    Mutagenesis is one of the critical outcomes of exposure by radiation or environmental mutagens. The molecular mechanism of the induced mutagenesis, which is one of the most important issues in this field, remains to be elucidated. A significant fraction of the induced mutation is generated through a cellular process, so-called DNA damage tolerance. In humans, two sub-pathways are regulated by ubiquitination of PCNA, one of the auxiliary factors of DNA replication; one is the error-prone pathway, translesion DNA synthesis, inducing point mutations, and the other is template switch, which is the error-free, in principle, but has a risk of genomic rearrangements. Therefore the regulation of the choice of two pathways is a crucial step for the maintenance of genetic stability. In this study, we examined the molecular mechanisms of the pathway choice by analysis of factors involved in the PCNA ubiquitination.

  5. 誘発突然変異頻度を適切に制御する損傷トレランス経路の生化学的分子基盤の確立

    2015.4 - 2018.3

    科学研究費補助金  基盤研究(B)

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  6. PCNAの新規脱ユビキチン酵素群の同定と複製後修復経路の多重制御メカニズム

    2014.4 - 2016.3

    科学研究費補助金 

  7. Analysis of mechanisms to tolerate for DNA replication blockage at DNA lesions

    Grant number:25241011  2013.4 - 2016.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (A)

    Chikahide Masutani, Masuda Yuji, Kanao Rie

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    Authorship:Collaborating Investigator(s) (not designated on Grant-in-Aid) 

    In human cells, multiple units of a PCNA homo-trimer are simultaneously mono-ubiquitinated at K164, which could activate unidentified mechanisms other than Polh-mediated translesion synthesis to replicate damaged DNA. Human Polh contains three PCNA-interacting motifs and a ubiquitin-interacting domain, all of which are included in the regulation of Polh-mediated translesion synthesis in a cooperative and redundant manner. A deubiquitinating enzyme, USP1, plays a crucial role in the regulation of DNA replication-coupled translesion DNA synthesis past UV-induced DNA lesions. USP7 is also involved in the PCNA deubiquitination and suppresses oxidative-stress-induced mutagenesis.

  8. 誘発突然変異と複製後修復経路の制御機構の解明に向けた生化学的分子基盤の確立

    2012.4 - 2015.3

    科学研究費補助金  基盤研究(B)

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  9. Development of a biological dosimeter to detect the DNA damage induced by low dose radiation and carcinogenic risk evaluation

    Grant number:22310037  2010 - 2012

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KAMIYA Kenji, SASATANI Megumi, IIDUKA Daisuke, MASUDA Yuji

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    It was explored the development of a biological dosimeter for low dose irradiation using our latest research data about mutagenesis. Rev1 Tg mice and Apc^Min/+mice, which are the model mice for human familial adenomatous polyposis coli, are used to generate Apc^Min/+; Rev1 Tg mice. The incidence of spontaneous and radiation-induced intestinal adenoma in Apc^Min/+; Rev1 Tg mice was significantly higher than that in Apc^Min/+; mice. Apc^Min/+; Rev1 Tg mouse is thought to be useful for the study of risk estimation of radiation-induced cancers.

  10. 突然変異誘発に関与する複製後修復経路の分子機構の解明に向けた生化学的基盤の確立

    2008.4 - 2012.3

    科学研究費補助金  基盤研究(B)

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  11. Development of bio-dosimetry for the evaluation of low dose radiation and carcinogenic risk estimation

    Grant number:17310036  2005 - 2007

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KAMIYA Kenji, MASUDA Yuji, TOYOSHIMA Megumi

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    We have tried to develop the hypersensitive mouse model and molecular bio-dosimery using DNA damage response proteins based on these functional analyses for the estimation of carcinogenic risk and dose after radiation exposure.
    1. Development of hypersensitive monitor mouse for the estimation of low-dose radiation exposure and analysis of its biological character
    The Y-family DNA polymerases play roles for maintenance of genetic stability. Malfunction of the polymerases affect cancer susceptibility. Revl, the number of the Y-family DNA polymerase, has deoxycytidyl transferase activity and plays the central role on the translesion DNA synthesis known as error-prone DNA repair. In order to develop hypersensitive model mouse for radiation exposure, we have generated Levi transgenic mice (Rev1 mouse). Therefore Levi mouse showed increased susceptibility to tumorigenesis after carcinogenic insult, we analyzed the biological character of this mouse. Furthermore, to determine how increasing .REV1 affects the biological phenotype of cells, human fibrosarcoma cells were transfected with hREV1 expression plasmid having tetracycline regulation system and then the stable sublines were isolated. We found that the cells expressing hREV1 were resistant to the cytotoxic effect of X-ray irradiation more than parental cells. This observation suggests the survived cells may increase the accumulation of mutations after the repair process of damaged DNA.
    2. Research on the development of molecular bio-dosimery for low dose radiation
    In order to develop new molecular bio-dosimery, we have focused our research on functional analysis of protein complex on damaged site of genome including Histone H2AX and REV1 complex which are visualized as foci and countable in cell nucleus. We have detected the possible candidate molecules for the molecular bio-dosimery. We found DNA damage-dependent modification of H2AX enhances chromatin dynamics. We also succeeded in analysis of translesion DNA sythesis on the reconstituteion system.

  12. 複製エラーを起こす損傷乗り越え型DNA合成酵素Revlの機能解析と発がん

    Grant number:17013061  2005

    科学研究費助成事業  特定領域研究

    神谷 研二, 増田 雄司

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    高発癌性の色素性乾皮症バリアントの原因蛋白質が,損傷乗り越え型DNAポリメラーゼYファミリーに属するPolηであることから,損傷乗り越えDNA合成酵素の機能と発癌との関連が注目されている。Yファミリーに属するREV1は,error-proneのDNA修復に関与し,突然変異の誘発に重要な役割を担っている。我々は,損傷乗り越えDNA合成酵素REV1の機能と発癌との関連を調べるために以下の解析を行った。
    (1)Rev1トランスジェニックマウス(Rev1マウス)の作成と発癌感受性の検討
    変異原に高感度なマウスを開発する為に,Rev1を過剰発現したRev1マウスを作成した。プロモーターには,遺伝子発現の制御が可能なメタロチオネインプロモーターを用いた。各臓器でユビキタスなRev1発現を認めたマウスを用いて表現型解析を行った。T細胞を用いた放射線誘発のTCR突然変異頻度は,対照群に比べ高い傾向を認めた。化学発癌剤MNUによるリンパ腫の誘発では,対照群に比べ有意にリンパ腫発生頻度が上昇し,変異原に対し発がん高感受性マウスであることが確認された。
    (2)REV1の機能解析とin vitro再構成系の確立
    REV1は損傷部位に対してCを取り込む酵素であるが,加えて損傷乗り越えDNA合成経路全体を調節する第二の機能をもつことが示唆されている。生化学的解析により,REV1がssDNA結合活性をもち,ssDNAに結合したREV1はそのssDNA上をスライディングして,損傷部位にターゲティングされることを明らかにした。この性質はREV1に特異的であり,REV1の最初のターゲットがssDNAである可能性を示唆すると同時に,損傷乗り越えDNA合成経路全体を調節するREV1の第二の機能に関与する可能性がある。一方,in vitro再構成系を確立するためPolδ,PCNA,FFC,及びRPAの全ての構成蛋白を精製した。この蛋白質群をin vitroで再構成し,この系によりDNAが7kb以上合成されることを確認した。

  13. ヒストンH2AX複合体のプロテオミクス解析による放射線ゲノム損傷の修復機構の解明

    Grant number:15651020  2003 - 2005

    科学研究費助成事業  萌芽研究

    神谷 研二, 増田 雄司, 井倉 毅

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    放射線によるゲノム障害に対する損傷応答や修復機構には,機能的蛋白質複合体が大きく関与している。その中でヒストンH2AXは,重要な役割をなすと推定されているが,それを解析するには,H2AXの機能的蛋白質複合体の網羅的解析が必要である。本研究では,ハーバード大学中谷が開発した機能的蛋白質複合体の精製法を応用し,tagを付与したH2AX蛋白質複合体を培養細胞,及びトランスジェニックマウスを用いて,生理的条件下でのH2AX機能的蛋白質複合体の精製法を開発し,その網羅的MS/MS解析を行った。今年度は,培養細胞からのH2AX複合体の精製とその機能解析について報告する。
    HeLa培養細胞にクローニングしたマウスH2AXをレトロウイルスを用いて導入し,安定形質株を樹立した。この細胞株より核分画を調整し,核抽出分画およびクロマチン分画においてH2AX複合体を精製した。H2AXを標識することにより2重鎖切断後のH2AX複合体の動態を解析した。その結果,H2AX複合体はゲノム損傷部位で高度に動的な状態にあることが判明した。このH2AXの動態は,損傷後のリン酸化とは関係なくモノユビキチン化に依存しており,このユビキチン化は,TIP60ヒストン・アセチラーゼによるアセチル化により制御されていた。一方,MS解析の結果,ヒストンH2AXは損傷依存的にTIP60ヒストンアセチル化酵素に結合し,損傷に伴いアセチル化されることが判明した。このアセチル化は,TIP60ノックダウン細胞では抑制されることからTIP60ヒストンアセチル化酵素が損傷依存的にヒストンH2AXのアセチル化を制御していることが示された。この様にH2AX複合体の動態は,ゲノム損傷後のH2AXのアセチル化とモノユビキチン化により制御されており,今まで不明であったゲノム損傷初期のクロマチン・ダイナミズムと細胞応答に重要な役割をなすものであることが推定された。

  14. Proteomics analysis of hEPC1 polycomb protein complex in DNA damaged repair.

    Grant number:15370078  2003 - 2004

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    IKURA Tsuyoshi, KAMIYA Kenji, MASUDA Yuji

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    Eukaryotic genome is the tightly packed into the chromatin, a hierarchically organized complex of DNA and histone and nonhistone proteins. This packing represents a common obstacle for most of the DNA functions. Recently, we revealed that TIP60 histone acetylase complex involved in DNA repair and apoptosis. However, it remains unknown how TIP60 complex involves in DNA repair. To better understand the mechanism of TIP60 complex in DNA repair, TIP60 complex purifies from chromatin soluble fraction after DNA damage. As a result, enhancer of polycomb (hEPC1), the component of TIP60 complex, dissociated with the TIP60 complex. In order to clarify the role of hEPC1 in DNA repair,
    We purified the hEPC1 from HeLa after induction of DNA damage. hEPC1 was included in multiple protein complex. MS/MS analysis indicated that kinase, metyltransferase enzyme, histone H2AX, TIP60 histone acetylase and ubiquitin related proteins were identified as a component of hEPC1 complex. Metyltransferase activity was observed. In addition, Histone H2AX is phosphorylated after DNA damage. The phosphorylation of H2AX was inhibited in HeLa cells expressing siEPC RNA suggested that the hEPC1 complex includes kinase domain.

  15. 損傷乗り越え複製においてDNA複製エラーを起こすRev1の機能解析と発がん

    Grant number:15023240  2003

    科学研究費助成事業  特定領域研究

    神谷 研二, 増田 雄司

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    ヒトREV1は,損傷乗り越え型DNAポリメラーゼYファミリーの一つで,鋳型塩基に対してdCMPを取り込むdCMP transferase活性を持つ。Yファミリーに属するXPVが色素性乾皮症の原因遺伝子として同定されたことから,損傷乗り越えDNA合成の機能変化と発癌との関連が注目されている。REV1遺伝子は,error-proneのDNA修復に関与し,突然変異の誘発に重要な役割を担っている。我々は,損傷乗り越えDNA合成に関与するREV1遺伝子の機能と発癌との関連を調べるために,REV1の生化学的解析を行った。その結果,ヒトREV1タンパク質のdCMP転移活性は,鋳型Gと脱塩基部位に対して効率が高いことから,REV1が脱塩基部位の損傷乗り越えDNA合成に重要な役割を担い,点突然変異を誘発する可能性が高いことが示唆された。この事から,REV1の機能亢進は,点突然変異を生成し易い遺伝的不安性を誘導し,発がんに関与する可能性が考えられた。一方,Rev1が相互作用する蛋白質を解析した結果,Rev7とPolκがRev1のC末端100アミノ酸残基に競合的に結合する事を生化学的に証明した。さらに,Polη,Polτも同じくRev1のC末端に結合することを見いだし,Rev1が他の損傷乗り越えDNAポリメラーゼと複合体を形成する一端を明らかにした。さらに,放射線や化学発がん剤に高感度なマウスを開発する為に,mRev1を過剰発現したトランスジェニック(Tg)マウスの作成を行った。遺伝子発現の制御が可能なメタロチオネインプロモーターの下流にmRev1遺伝子を組み込んだMT-1プラスミドを構築し,Tgマウスの作成を行った。その結果,現在までに7系の独立したRev1トランスジェニックマウスを得た。これらマウスの各臓器よりmRNAを取り出し,mRev1トランスジーンの発現をRT-PCR法で検討した。各臓器でmRev1トランスジーンが発現していることを確認した。

  16. Development of bio-dosimetry for the evaluation of low dose radiation and carcinogenic risk estimation

    Grant number:14380252  2002 - 2004

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KAMIYA Kenji, MASUDA Yuji, IKURA Tsuyoshi

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    We have tried to develop the hypersensitive mouse model and molecular bio-dosimery using DNA damage response proteins for the estimation of carcinogenic risk and dose after radiation exposure.
    1.Development of hypersensitive mouse model for radiation exposure
    Rev1 protein belongs to a family of translesion DNA polymerases. Rev1 is responsible for error-prone translesion synthesis and play a role in mutagenesis induced by DNA damage. REV1 is deoxycytidyltransferase that incorporates dCMP opposite template abasic sites.
    In order to develop hypersensitive mouse model for radiation exposure, We have developed transgenic mouse (Tg) over expressing Rev1 gene under the constitutive zinc-induced transcriptional activation promoter. We've succeeded in establishing 7 Tg mouse line expressing Rev1 transgene. We examined sensitivity and mutation frequency of T-cell receptor (TCR) after radiation exposure, and found that Tg mouse was apt to have higher mutation frequency of TCR than normal mouse.
    2.Development of molecular bio-dosimery for low dose radiation
    In order to develop molecular bio-dosimery, We have focused our research on functional analysis of Histone H2AX complex which is phosphorylated after induction of DNA damage (γ-H2AX) and visualized as foci in cell nucleus. We found that H2AX became highly mobile after induction of DSBs. We further find that mobilization depends not on phosphorylation but rather on ubiquitination, and that ubiquitination of H2AX is, in turn, regulated by TIP60 histone acetylase which implicates TIP60 in DNA repair. These results suggest that mobilization of H2AX is an early and necessary step in repair of DNA DSB.

  17. 損傷乗り越え複製においてDNA複製エラーを起こすRev1の機能解析と発がん

    Grant number:14026031  2002

    科学研究費助成事業  特定領域研究

    神谷 研二, 増田 雄司

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    ヒトREV1遺伝子は,損傷乗り越え型DNAポリメラーゼをコードするumuC/dinB/XPV遺伝子ファミリーのメンバーであり,鋳型塩基に対してdCMPを取り込むdCMP transferase活性を持つ。XPV遺伝子は色素性乾皮症の原因遺伝子として同定されたことから,損傷乗り越えDNA合成の機能変化と発癌との関連が示唆されている。また,REV1遺伝子は,error-proneのDNA修復に関与し,突然変異の誘発に重要な役割を担っている。我々は,損傷乗り越えDNA合成に関与するREV1遺伝子の機能と発癌との関連を調べるために,REV1の生化学的解析を行った。精製したREV1タンパク質のdNMP転移反応をプライマー伸長法により測定した結果,鋳型G及び脱塩基部位に対して同等に最も効率よくdCMPを挿入した。この結果は,REV1が脱塩基部位の損傷乗り越えDNA合成に重要な役割を担い,その部位にdCMPを挿入した場合は,点突然変異を誘発する可能性が高いことを示す。この事から,REV1の機能亢進は,点突然変異を生成し易い遺伝的不安性を誘導し,発がんに関与する可能性が示唆された。一方,REV1が相互作用する蛋白質を解析した結果,REV7がREV1のC末端に結合する事を生化学的に証明し,REV1が他の修復蛋白質と複合体を形成する一端を明らかにした。さらに,Rev1トランスジェニックマウスの作製を進め,36匹のマウスを得たので,今後トランスジーンの発現を確認する

  18. 哺乳類の突然変異誘発に関与するDNA複製装置のin vitroでの再構成

    Grant number:13780559  2001 - 2002

    科学研究費助成事業  若手研究(B)

    増田 雄司

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    Grant amount:\2100000 ( Direct Cost: \2100000 )

    DNA損傷の多くは、正常な塩基対合を防げることによりDNA合成を阻害することが知られている。ところが最近、これらの損傷DNAを鋳型として、効率よくDNA合成を行う特殊なDNAポリメラーゼ(損傷乗り越え型DNAポリメラーゼ)が多数発見された。この損傷乗り越え型DNAポリメラーゼは原核生物から真核生物まで広く保存されており、DNA複製の停止を回避するために重要な機能を担っていることが明らかとなってきた。
    本研究では、哺乳類の損傷乗り越えDNA合成の分子機構を明らかにするために、損傷乗り越え型DNAポリメラーゼの一つであるREV1遺伝子を同定し、その機能解析を行った。ヒトREV1遺伝子は1250アミノ酸残基からなるタンパク質を、マウスRev1遺伝子は1249アミノ酸残基からなるタンパク質をコードすることが分かった。REV1/Rev1タンパク質の生化学的解析を行うために、これらの遺伝子を大腸菌で過剰発現させた後、各種クロマトグラフィーによってREV/Rev1タンパク質を精製した。REV1/Rev1タンパク質の酵素活性をプライマー伸長反応により測定したところ、これらのたんぱく質は鋳型のグアニンに特異的にdCMPを重合するdCMP転移酵素であることを証明した。次に、REV1/Rev1タンパク質の損傷乗り越えDNA合成活性を、ウラシル残基と脱塩基部位を鋳型に持つモデル基質を用いて測定した。脱塩基部位は鋳型塩基が欠落した構造のために複製型DNAポリメラーゼによるDNA合成を強く阻害する。ところがREV1/Rev1タンパク質は脱塩基部位に対してグアニンと同程度の効率でdCMPを取り込むことが明らかとなった。Rev1タンパク質のこの酵素活性が、損傷を乗り越えてDNA合成を行うための重要な機能であると思われる。さらに、ヒトREV1タンパク質については、多数の欠失型タンパク質を作成し、dCMP転移活性と、DNA結合活性に必要な領域を同定した。
    さらに本研究では、ヒトREV1タンパク質とヒトREV7たんぱく質が安定なヘテロ二量体を構成することを示した。この複合体の酵素活性はREV1単独のそれと同等であったことから、REV7タンパク質はREV1とそれ以外のタンパク質との相互作用を仲介し高次複合体を構成するために必要なサブユニットであると考えられた。

  19. Development of molecular bio-dosimeiry and monitor mice for the detection of radiation dose exposed by tritium water

    Grant number:12558049  2000 - 2002

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (B)

    KAMIYA Kenji, SUMII Masaharu, MASUDA Yuji, KOMATSU Kenshi, IKURA Tsuyoshi

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    We tried to develop bio-dosimetry system of tritium water at the level from whole body to molecule.
    1) Development of Revl transgenic mice which are sensitive to radiation exposure
    We characterized mouse and human Revl gene which was a member of the UmuC/DinB/XPV gene family, played important roles in spontaneous mutations. Biochemical analysis of the mouse Revl protein revealed that the mouse Revl protein possessed a deoxycytidyl transferase activity as human REV1 protein. The expression of mouse Revl in embryonic fibroblasts was induced by radiation exposure. Based on these knowledge, we try to establish Revl transgenic mouse to develop the hypersensitive mouse model to radiation exposure. We introduced MT-1 plasmid carrying mRevl down stream the metallotuionein promoter into C57BLmice. We already got 36 mice carrying mRevl. We will check the expression of mRevl.
    2) Development of molecular bio-dosimetry system for tritium water
    In repair machinery of DNA double trand break by radiation, Historic H2AX, Ku70, Ku80 and Tip60 are thought to play an important role. We observed that H2AX was phosphorylated (γ-H2AX) and formed foci after irradiation. In order to use the foci formation for the dosimetry of DNAdouble strand breaks, we purify the constitutive H2AX complex and identify its new components by MS/MS spectrometric analysis. We prepared antibody against these components and performed the immunohistochemical analysis to detect the foci at DNAdouble strand breaks. Furthermore, we found that NBS1 localized toγ-H2AX foci after radiation exposure. Relationship between numbers of foci and DNAdouble strand breaks is under investigation.

  20. Analysis of molecular mechanism of radiation-induced cancer and risk estimation

    Grant number:11680549  1999 - 2001

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    KAMIYA Kenji, IKURA Tsuyoshi, SUMII Masaharu, MASUDA Yuji

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    To clarify the molecular mechanism of radiation-carcinogenesis, and apply it to the risk estimation, we conducted two experiments. Firstly, we analyzed the expression of genes in radiation-induced-mouse hepatomas. Mouse hepatomas were induced in B6C3F1 mice by 3Gy of ^<60>Coγ-ray exposure, and mRNAs were isolated from hepatomas and normal liver in the same mice. We identified differentially expressed genes by differential display technique. We found nineteen differentially expressed genes in hepatomas. Expressions of five genes were decreased and those of other fourteen genes were increase in hepatomas, including novel three genes named CRAD3 that was a member of cis-retinol/androgen dehydrogenase (CRAD) family, Sdf211 that was a member of Pmt/rt family, and A141-36 whose homology was not identified. CRAD plays an important role in androgen metabolism, which converts inactive 3α-adiol, into active dihydrotestosterone, (oxidative 3α-hydroxysteroid dehydrogenase activities : oxidative 3α-HSD activities) and consequently increases androgen activity. Actually, oxidative 3α-HSD activity in mouse hepatomas was found to be higher than that in normal liver at physiological 3α-adiol level. Dihydrotestosterone is well known to promote hepatocarcinogenesis. Therefore, the over-expression of CRAD3 must modify the radiation-induced mouse hepatocarcinogenesis by increasing local dihydrotestosterone level. Secondly, we try to clarify the involvement of spontaneous mutations in radiation carcinogenesis, because similarity of mutation spectra between radiation-induced and spontaneous cancers was well documented. We characterized mouse and human Revl gene which was a member of the UmuC/DinB/XPV gene family, played important roles in spontaneous mutations. Biochemical analysis of the mouse Rev1 protein revealed that the mouse Rev1 protein possessed a deoxycytidyl transferase activity as human REV1 protein. The expression of mouse Rev1 gene of primary embryonic fibroblasts in culture was induced by radiation exposure. This observation might be important, because the biochemical property suggested that the activity of the Rev1 protein was required for bypassing oxidative DNA damage by translesioh DNA synthesis during DNA replication.

  21. ヒトとマウス肝癌のLOH領域の相同性を利用した肝癌抑制遺伝子の単離に関する研究

    Grant number:10877039  1998 - 2000

    科学研究費助成事業  萌芽的研究

    隅井 雅晴, 増田 雄司, 神谷 研二

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    B6C3F1マウスの肝癌より樹立した肝癌細胞株には,高頻度に4番染色体のLOHが存在した.LOHの最小欠失領域はD4Mit37領域の2cMの範囲で,この領域は肝細胞の不死化遺伝子座(Lci)を含んだ.このLOH領域は,ヒト染色体の1p32-36に相同し,ヒト肝癌でもこの領域にLOHが存在する事から,ここに肝癌抑制遺伝子が存在すると推定されている.そこで我々は,4番染色体にLOHを有する細胞株とそうでない細胞株を用いて,mRNAの発現レベルが変化している遺伝子の同定を行う目的でdifferential display法による解析を行った.その結果,LOHを有する細胞株においてmRNAの発現量が増加しているマウス新規遺伝子A141-36のクローニングに成功した.同時に,そのヒトの相同遺伝子であるヒトA141-36をクローニングした.マウスA141-36遺伝子は,マウス肝癌の9例中7例(78%)で発現が増加していた.また,マウスA141-36遺伝子の発現は,軟寒天培地でコロニー形成能を有するマウス肝癌細胞株で増加している傾向を認めた.一方,ヒトA141-36は,約2500bpの塩基配列からなり748個のアミノ酸をコードしていた.ヒトA141-36は,マウスA141-36とidentity34%,similarity44%であった.ヒトA141-36遺伝子の組織発現は,精巣で強く発現していたが,他の組織では殆ど発現を認めなかった.ヒトA141-36遺伝子の発現は,ヒト肝癌では全例(5例中5例)で増加していた.さらに,慢性骨髄性白血病細胞株K-562,大腸癌細胞株SW480,前立腺癌細胞株PC3,DU145などでも発現亢進を認めた.従って,ヒトA141-36の発現増加は,肝癌以外の悪性腫瘍においても発症と関係する可能性が考えられた.抗ペプチド抗体を用いた免疫染色により,ヒトA141-36は核に存在する蛋白であることが判明した.現在,更に機能解析を進めている.一方,LOHを有する細胞株で発現が低下している遺伝子としてInsulin-like growth factor binding protein-related protein-1(IGFBP-rP1/IGFBP-7)を同定した.この遺伝子は,原発性肝癌においても発現低下が認められた.
    肝癌細胞株では足場非依存性増殖能の強い細胞株においてIGFBP一rP1の発現低下が著明であった.
    IGFBP-rP1を強制発現した細胞株では,増殖速度,足場非依存性増殖能,in vivoでの腫瘍形成能の低下を認めた.またヒト肝癌もIGFBP-rP1の発現低下を認めた.これらの結果より,IGFBP-rP1の発現低下は肝癌の発生,増殖に関与していることが示唆された.

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