1998 Fiscal Year Annual Research Report

Dna蛋白のATPase活性調節による,DNAの再複製開始抑制機構の解明

Research Project

Project/Area Number	10162210
Research Institution	Okayama University
Principal Investigator	水島徹岡山大学, 薬学部, 助教授 (00264060)
Keywords	DNA複製 / がん / 抗がん剤 / ATPase
Research Abstract	DNA複製研究の重要な課題の一つに、「どのような機構で、複製された直後の複製開始点からの再複製開始が抑制されているか。」という問題がある。この機構が働かなくなると、一細胞あたリーコピー以上の染色体が存在することになることを考えても、上記の機構は生命体にとって根本的なものであることが分かる。私は、大腸菌複製開始蛋白DnaAのATPase欠損変異蛋白の細胞内発現が再複製開始抑制を解除することを見いだし、DnaAのATPaseがこの再複製開始抑制に関与することを示した。また、このATPaseの促進因子を見いだし、これがDNA複製反応によって活性化されることも見いだした。以上から、再複製開始抑制の分子機構に対する全く新しいモデルを提唱した。それは、複製反応自体が、DnaAのATPase活性の促進因子を活性化し、DnaA蛋白を不活性なADP結合型へ変換するというものである。さらに私は、この促進因子を遺伝学的にDNAポリメラーゼのβサブユニットであることを見いだした。この結果、DNA複製反応依存のATPase促進をよく説明するものである。一方、酵母からヒト細胞まで真核細胞すべてに存在する複製開始因子ORCも内在性のATPaseを有していること及び活性発現にATP結合を要求することから私は、真核生物にも大腸菌同様の再複製開始抑制機構が存在する可能性を考えた。私は、酵母のORCとDnaAの比較から、酵母のORCのATPaseドメインの決定に初めて成功した。そしてこれまでに、ATPase活性の欠損した変異ORCを構築しその細胞内発現が細胞を死滅させることを示した。

Research Products
(15 results)

All Other

All Publications (15 results)

[Publications] Mizushima,T: "Site-directed mutational analysis of the ATP-binding of DnaA Protein" J.Biol.Chem.273. 20847-20851 (1998)
[Publications] Hase,M: "Site-directed mutational analysis for the membrane-binding of DnaA protein" J.Biol.Chem.273. 28651-28656 (1998)
[Publications] Tamai,E: "Conversion of temperature-sensitive to-resistant gene expression due to mutations in the promoter region of the melibiose operon in Escherichia coli." J.Biol.Chem.273. 16860-16864 (1998)
[Publications] Sakamoto,K.: "Effect of environmental factors on the dominant lethality caused by expression of a mutated DnaA Protein with decreased intrinsic ATPase activity" FEMS.Micro.Lett.159. 93-97 (1998)
[Publications] Kurokawa,K: "A Stimulation factor for the hydrolysis of ATP Bound to DnaA Protein, the initiator of chromosomal DNA" Biochem.Biophys.Res.Commun.243. 90-95 (1998)
[Publications] Nozaki,K.: "A new Na^+/H^+ antiporter, NhaD, of Vibrio parahaemolyticus." Biochim.Biophys.Acta. 1369. 680-683 (1998)
[Publications] Hase,M.: "Effect of glycerol on the affinity of DnaA protein for ATP in the presence of cardiolipin." J.Biochem. 123. 680-683 (1998)
[Publications] Suzuki,E.: "Alteration in the contents of unsaturated fatty acids in dnaA mutants of Escherichia coli." Mol.Microbiol.28. 95-102 (1998)
[Publications] Morita,Y: "NorM, a putative multidrug efflux protein, of Vibrio parahaemolyticus and its homolog in Escherichia coli." Antimicrob.Agents.Chemother.42. 1778-1782 (1998)
[Publications] Mine,T: "Envidence for chloramphenicol/H^+ antiport in Cmr (MdfA) system of Escherichia coli and properties of the antiporter." J.Biochem.124. 187-193 (1998)
[Publications] Suzuki,E: "Alteration in contents of unsaturated fatty acids in mutants defctive in DNA replication." Biol.Pharm.Bull. 21. 657-661 (1998)
[Publications] Ohba,A: "Amounts of proteins altered by mutations in the pgsA gene of Escherichia coli." Biol.Pharm.Bull.(in press).
[Publications] Mizushima,T.: "Supression of Ethanol-induced Apototic DNA Fragmentation by Geranylgeranylacetone in Cultured Guinea Pig Gastric Mucosal Cells." Digest.Dis.Sci. (in press).
[Publications] Ogawa,W: "Cloning and expression of the gene for the Na+-coupled serine transporter from Escherichia coli and characteristics of the transporter." J.Bacteriol.(in press).
[Publications] Hiramatsu,T: "A putative multisubunit Na+/H+ antiporter from Staphylococcus aureus." J.Bacteriol.(in press).

1998 Fiscal Year Annual Research Report

Dna蛋白のATPase活性調節による,DNAの再複製開始抑制機構の解明

Principal Investigator

水島 徹 岡山大学, 薬学部, 助教授 (00264060)

Research Products

[Publications] Mizushima,T: "Site-directed mutational analysis of the ATP-binding of DnaA Protein" J.Biol.Chem.273. 20847-20851 (1998)

[Publications] Hase,M: "Site-directed mutational analysis for the membrane-binding of DnaA protein" J.Biol.Chem.273. 28651-28656 (1998)

[Publications] Tamai,E: "Conversion of temperature-sensitive to-resistant gene expression due to mutations in the promoter region of the melibiose operon in Escherichia coli." J.Biol.Chem.273. 16860-16864 (1998)

[Publications] Sakamoto,K.: "Effect of environmental factors on the dominant lethality caused by expression of a mutated DnaA Protein with decreased intrinsic ATPase activity" FEMS.Micro.Lett.159. 93-97 (1998)

[Publications] Kurokawa,K: "A Stimulation factor for the hydrolysis of ATP Bound to DnaA Protein, the initiator of chromosomal DNA" Biochem.Biophys.Res.Commun.243. 90-95 (1998)

[Publications] Nozaki,K.: "A new Na^+/H^+ antiporter, NhaD, of Vibrio parahaemolyticus." Biochim.Biophys.Acta. 1369. 680-683 (1998)

[Publications] Hase,M.: "Effect of glycerol on the affinity of DnaA protein for ATP in the presence of cardiolipin." J.Biochem. 123. 680-683 (1998)

[Publications] Suzuki,E.: "Alteration in the contents of unsaturated fatty acids in dnaA mutants of Escherichia coli." Mol.Microbiol.28. 95-102 (1998)

[Publications] Morita,Y: "NorM, a putative multidrug efflux protein, of Vibrio parahaemolyticus and its homolog in Escherichia coli." Antimicrob.Agents.Chemother.42. 1778-1782 (1998)

[Publications] Mine,T: "Envidence for chloramphenicol/H^+ antiport in Cmr (MdfA) system of Escherichia coli and properties of the antiporter." J.Biochem.124. 187-193 (1998)

[Publications] Suzuki,E: "Alteration in contents of unsaturated fatty acids in mutants defctive in DNA replication." Biol.Pharm.Bull. 21. 657-661 (1998)

[Publications] Ohba,A: "Amounts of proteins altered by mutations in the pgsA gene of Escherichia coli." Biol.Pharm.Bull.(in press).

[Publications] Mizushima,T.: "Supression of Ethanol-induced Apototic DNA Fragmentation by Geranylgeranylacetone in Cultured Guinea Pig Gastric Mucosal Cells." Digest.Dis.Sci. (in press).

[Publications] Ogawa,W: "Cloning and expression of the gene for the Na+-coupled serine transporter from Escherichia coli and characteristics of the transporter." J.Bacteriol.(in press).

[Publications] Hiramatsu,T: "A putative multisubunit Na+/H+ antiporter from Staphylococcus aureus." J.Bacteriol.(in press).

水島徹岡山大学, 薬学部, 助教授 (00264060)