2019 Fiscal Year Final Research Report
Elucidation of thermo-adaptive evolution strategy by genome network analysis of thermo-adapted E. coli
| Project/Area Number |
17K19360
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Molecular and Genome biology and related fields
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| Research Institution | Toho University |
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Principal Investigator |
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| Project Period (FY) |
2017-06-30 – 2020-03-31
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| Keywords | 高温適応進化 / 大腸菌 / ゲノム解析 / 必須遺伝子 / プロテオスタシス / シャペロニン |
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| Outline of Final Research Achievements |
In this research, we have developed two independent thermophilic E. coli strains by experimental thermo-adaptive evolution and analyzed them. Genome analyses showed that mutation rate of strains increased and peak out later in evolution.Interestingly, GC contents of genome DNA were gradually decreased with evolution. In the gene region of proteostasis network factors, mutation rate was about 3 times higher than in other regions.All 4 essential genes in proteostasis network were mutated in thermo-adaptive evolution. A part of mutations in essential genes of thermo-adapted E. coli included the change to the same amino acid with the homologous genes of thermophilic bacteria. These essential genes were global regulator genes. Mutation of groL (coded chaperonin GroEL) was throwback mutation in E. coli species evolution.
These results indicated that proteostasis network change was important for E. coli thermo-adaptive evolution.
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| Free Research Field |
分子細胞進化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究成果により、細菌の高温適応進化戦略の一端が明らかになる。また、本研究で得られた高温適応進化大腸菌と、好熱菌・超好熱菌のゲノム情報と比較解析することで、進化の普遍性、可逆性、多様性に関する知見が得られる。今回明らかとなった大腸菌高温適応戦略をもちいて、更なる高温で安定増殖し、遺伝子操作可能な物質生産宿主等としての高温適応大腸菌の創出が可能となる。本研究成果に、他のストレス適応進化させた大腸菌の情報を統合することで、様々な外部ストレスへの適応戦略が考察可能となり、新しい抗生物質ターゲットの探索等が可能となる。
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