細胞周期を制御する新しい遺伝子の解析

• Project/Area Number: 06283201
• Research Category: Grant-in-Aid for Scientific Research on Priority Areas (A)
• Allocation Type: Single-year Grants
• Research Institution: The University of Tokyo
• Principal Investigator: 岡山 博人 東京大学, 大学院・医学系研究科, 教授 (40111950)
• Project Period (FY): 1999
• Project Status: Completed (Fiscal Year 1999)
• Budget Amount: ¥143,000,000 (Direct Cost: ¥143,000,000); Fiscal Year 1999: ¥31,000,000 (Direct Cost: ¥31,000,000); Fiscal Year 1998: ¥30,000,000 (Direct Cost: ¥30,000,000); Fiscal Year 1997: ¥28,000,000 (Direct Cost: ¥28,000,000); Fiscal Year 1996: ¥25,000,000 (Direct Cost: ¥25,000,000); Fiscal Year 1995: ¥16,000,000 (Direct Cost: ¥16,000,000); Fiscal Year 1994: ¥13,000,000 (Direct Cost: ¥13,000,000)
• Keywords: 発ガン / 足場非依存性細胞周期開始 / Cdk6 / 造血細胞 / 分裂酵母 / 姉妹染色体結合 / S期 / polη / Cdk4 / 発癌刺激 / 分化制御 / RNA結合タンパク / G1停止 / 発がん / 足場非依存性増殖 / サイクリンD / CKI / チェックポイント / 細胞周期 / G1 / G2 / 哺乳動物 / センサー / 癌形質 / チェックポイント制御 / 細胞分化 / MAPキナーゼ / Cdc2キナーゼ / チェックポイント機構 / cdk4 / DNA障害 / DNAポリメラーゼα

Research Abstract

今年度は、発ガンの本体である足場非依存性細胞周期開始の機構と、ガンの進行原動力とされている染色体の不安定化に深く関わる姉妹染色体の結合形成に必須な分裂酵母の2種類の新規遺伝子(eso1^+,abs1^+)の機能の解明を進めた。
2つの増殖因子によって可逆的にガン化するラット繊維芽細胞への特異抗体の微量注入実験から、発ガン刺激によってCdk6キナーゼが細胞周期の開始に使われはじめることが明らかになった。さらに、Cdk6の細胞開始への使用が、キナーゼ自身の活性制御や細胞内局在の制御によるのではないことが、Cdk6の高発現株の解析からも判明した。元来足場非依存性細胞周期開始を行う造血系細胞ではCdk6が主に使われていることから、この細胞で見られた発ガン刺激による足場非依存性細胞周期開始が造血系細胞と同じ機構でおこっている可能性が示唆された。
ガン進行の原動力とされる染色体の不安定化は、姉妹染色体の結合不全でも誘発される。分裂酵母から新規に同定したeso1^+は、ピリミジン2量体を乗り越えてDNA合成ができるpolηとS期で複製された姉妹染色体同士の結合形成を行う蛋白質との融合蛋白をコードし、複製フォークの構成因子としてDNA複製進行と共にこの2つの異なった反応を触媒することが判明した。abs1^+は、eso1^+と相互作用する遺伝子として単離されたもので、abs1^+を欠損させるとeso1^+がなくても姉妹染色体同士の結合形成が可能となる一方で、姉妹染色体同士の結合が極めて不安定になることから、この遺伝子によってコードされる蛋白は、姉妹染色体同士の結合を安定化するのみならずおそらく姉妹染色体以外の染色体同士の結合を防ぐ役割をも果たしているものと考えられた。

Research Products

• [Publications] Suto, K. et al.: "A Double-Strand Break Repair Component is Essential for S Phase Completion in Fission Yeast Cell cycling"Molecular Biology of the Cell. 10. 3331-3343 (1999)
• [Publications] Jinno, S. et al.: "Oncogenic stimulation recruits cyclin-dependent kinase in the cell cycle start in rat fibroblast"Proceeding of the National Academy of Science. 96・23. 13197-13202 (1999)
• [Publications] Tominaga, K. et al.: "Role of Human Cds1 (Chk2) Kinase in DNA Damage Checkpoint and Its Regulation by p53"J. Biol. Chem.. 274. 31463-31467 (1999)
• [Publications] Okazaki, K. et al.: "The polyubiquitin gene is essential for meiosis in fission yeast"Exp. Cell. Res.. 254. 143-152 (2000)
• [Publications] Kizaka-Kondoh, S. et al.: "Role of TGF-b in EGF-induced transformation of NRK cells is sustaining high level EGF0Signaling"FEBS Let. 466. 160-164 (2000)
• [Publications] Masuda, M. et al.: "Genetic Studies with the Fission Yeast Schizosaccharomyces pombe Suggest Involvement of Wee1, Ppa2, and Rad24 in Induction of Cell Cycle Arrest by Human Immunodeficiency Virus Type 1 Vpr"J. Virol.. 74. 2636-2646 (2000)
• [Publications] Ota,S. et al.: "Constitutive association of EGF receptor with the Crkll-23 mutant that inhibits transformation of NRK cells by EGF and TGF-beta" Cell Signal. 10. 283-290 (1998)
• [Publications] Jinno,S. et al.: "Cell cycle start from quiescence controlled by tyrosine phosphorylation of Cdk4" Oncogene. 18. 565-577 (1999)
• [Publications] Tnanaka,H. et al.: "Fission Yeast Cdc24 Is a Replication Factor C-and Proliferating Cell Nuclear Antigen-Interacting Factor Essential for S-Phase Completion" Molecular and Cellular Biology. 19・2. 1038-1048 (1999)
• [Publications] Yamamoto,H. et al.: "Isolation of a mammalian homologue of a fission yeast differentiation regulator" Molecular and Cellular Biology. (in press). (1999)
• [Publications] Murakami,H.et al.: "Cell cycle checkpoint control" Exp.& Mol.Med.29. 1-11 (1997)
• [Publications] Hao,Z.et al.: "A zinc finger protein required for stsitinary phase viability in fission yeast." J.Cell Sci.110. 2557-2566 (1997)
• [Publications] Yamaguchi,S.et al.: "A WD repeat protein controls differentiation and the cell cycle by negatively regulating Cdc2/B-type cyclin complexs." Mol.Biol.Cell. 8. 2475-2486 (1997)
• [Publications] Okazaki,N.et al.: "Novel Factor Highly Coserved among Eukaryotes Controls Sexual Development in Fission Yeast." Mol.Cell.Biol.18. 887-895 (1997)
• [Publications] Okayama,H.et al.: "Cell cycle control in fission yeast and mammals:ldentification of new regulatory mechanisms." Adv.Cancer Res.69. 17-62 (1996)
• [Publications] Kato,T.Jr.et al.: "Stress signal,mediated by a Hog1-like MAP kinase,controls sexual development in fission yeast." FEBS Let.378. 207-212 (1996)
• [Publications] Yoshida,S.et al.: "Assembly of Hepatitis C Virus Antigens Expressed from a Recombinant Vaccinia Virus." Proc.Japan Acad.72. 73-78 (1996)
• [Publications] Masuda,A.et al.: "Role of a signal transduction pathway which controls disassembly of microfilament bundles and suppression of high-molecular weight tropomyosin expression in oncogenic transformation of NRK cells." Oncogene. 12. 2081-2088 (1996)
• [Publications] Kizaka-Kondoh,S.et al.: "Crkll signals from growth factor receptor to ras." Proc.Natl.Acad.Sci.USA. 93. 12177-12182 (1996)
• [Publications] Sturm,S.,and Okayama,H.: "Domains determing the functional distinction of the fission yeast cell cycle start molecules Res1 and Res2." Mol.Biol.Cell. 7. 1967-1976 (1996)
• [Publications] Shimizu,M.et al.: "The G1/S boundary-specific enhancer of the rat cdc2 promoter." Mol.Cell.Biol.15. 2882-2892 (1995)
• [Publications] Murakami.H et al.: "A kinase from fission yeast responsible for blocking mitosis in S phase." Nature. 374. 817-819 (1995)
• [Publications] Terada,Y.et al.: "Requirement for tvrosine phosphorylation of cdk4 in G1-arrest induced by ultraviolet irradiation." Nature. 376. 358-362 (1995)
• [Publications] Nakashima,N.et al.: "Fission yeast Rep2 is a putative transcriptional activator subunit for the cell cycle‘start'function of Res2-Cdc10." EMBO J.14. 4794-4802 (1995)
• [Publications] Bertolotti,R.et al.: "Liver fructose-1,6-bisphosphatase cDNA:trans-complementation of fission yeast and characterization of two human transcripts" Differentiation. 59. 51-60 (1995)
• [Publications] Kato,T.Jr.et al.: "Stress signal,mediated by a Hog1-like MAP kinase,controls sexual development in fission yeast." FEBS Let.378. 207-212 (1996)
• [Publications] Okayama,H.: "Cell cycle control in fission yeast and mammals:ldentification of new regulatory mechanisms" Adv.Cancer Res.(in press), (1995)
• [Publications] Jinno,Shigeki: "Cdc25A is a novel phosphatase functioning early in the cell cycle." EMBO J.13. 1549-1556 (1994)
• [Publications] Murakami,Shigeki: "Highly sensitive detection of viral RNA genomes in blood specimens by an optimiged reverse transcription-polymerace chain reaction." J.Med.Virol.43. 175-181 (1994)
• [Publications] Manabe,Sadao: "Production of nonstructural proteins of hepatitis C virus reguires a putative viral protease encoded by NS3." Virol.196. 636-644 (1994)
• [Publications] Sugiyama,Akio: "A zinc finger protein controls the on set of premeiotic DNA synthesis of fission yeast in a Mei2-independent cascade." EMBO J.13. 1881-1887 (1994)
• [Publications] Miyamoto,Masaaki: "res2^+.a new member of cdc10^+/SW14 tamily,controls the “start" of mitotic and meietic cycles in tission yeast." EMBO J.13. 1873-1880 (1994)
• [Publications] Obara-Ishihara,Tomoko: "A B-type cyclin.regulates conjugation via interaction with cell cycle “start" genes in fission yease." EMBO J.13. 1863-1872 (1994)