| Project/Area Number |
17310113
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
基礎ゲノム科学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOBAYASHI Ichizo The University of Tokyo, Graduate School of Frontier Sciences, Professor (30126057)
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| Co-Investigator(Kenkyū-buntansha) |
HANADA Naofmi The University of Tokyo, Graduate School of Frontier Sciences, Assistant Professor (00396855)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥15,500,000 (Direct Cost: ¥15,500,000)
Fiscal Year 2006: ¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 2005: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | genome / selfish gene / restriction enzyme / mobile element / genome evolution / bacterial genome / pathogenic bacteria / phage |
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| Research Abstract |
(1) Propagation of restriction-modification systems and their hosts
(1-1) We demonstrated that a thermosensitive mutation in EcoRII modification enzyme enhances maintenance of EcoRII restriction-modification system.
(1-2) We demonstrated that space structure is critical in the evolution of restriction-modification gene complex and other addictive genes.
(1-3) We demonstrated that transcription from promoters in EcoRI restriction-modification gene complex is inhibited by intragenic reverse promoters.
(1-4) We demonstrated suicidal defense of bacteria against invasion of genome methylation systems such as restriction-modification systems.
(2) Restriction-modification systems and genome rearrangements
(2-1) We demonstrated restriction-dependence of IS-mediated transposition of a restriction-modification gene complex.
(2-2) We demonstrated that host attack following loss of a restriction-modification gene complex is counteracted by RecFOR homologous recombination.
(2-3) We demonstrated that Type I
… More
II restriction occurs after bacteriophage genome replication and that phage-mediated homologous recombination can repair the resulting damages.
(2-4) We elucidated conditions for evolution of gene conversion repairing genome breakage.
(3) Reconstruction of evolutionary processes in the formation of genome polymorphisms through genome comparison.
(3-1) We developed methods and a tool for inference of evolutionary processes through comparison of closely-related genomes.
(3-2) From comparison of Neisseria genomes, we found that a phage genome is integrated into the genome by the phage-carried transposase homologue.
(3-3) We were able to reconstruct formation of apparently complex genome rearrangements by action of mobile elements.
(3-4) We compared multiple genomes of Staphylococcus aureus to understand evolution of their paralogue clusters.
(4) Discovery of restriction enzyme of a novel fold and properties.
From comparison of closely-related genomes, we found a restriction enzyme PabI with novel properties such as Mg-independence. We expressed them in a wheat-germ-based cell-free expression system to solve its crystal structure and found a novel, 'half-pipe' structure. The cognate modification enzyme was also characterized. Less
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