| Project/Area Number |
16K18593
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Evolutionary biology
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| Research Institution | Sophia University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Project Status |
Completed (Fiscal Year 2018)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2018: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | hatching enzyme / egg envelope / recombinant protein / enzyme activity / medaka / adaptation / hatching / 孵化酵素 / 環境適応 / 多重コピー遺伝子 |
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| Outline of Final Research Achievements |
Embryos are surrounded by egg envelope to protect from physical stress, and then, secrete hatching enzymes HCE and LCE to dissolve the envelope at hatching. In medaka, two isoforms of HCE having high sequence similarity show different optimum salinities for egg envelope digestion. In this study, we tried to figure out the amino acid residues responsible for the different optimal salinity between the two isoforms. We constructed various kinds of mutant recombinant HCEs, and determined their optimal salinity. As the results, we found that the change of optimal salinity was caused by several amino acid residues. We further determined nucleotide sequence of the HCE cluster of 5 fishes from genus Oryzias. Then, the optimal salinity of HCE of each species was examined from their recombinant HCEs. Based on these data, three amino acid residues were suggested to be most important for different optimal salinity of HCE.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究の特色は、第一に、タンパク質レベルの実験を通して適応進化を論じる点である。本研究は、多重コピー遺伝子の活性の多様性と適応進化との関係について考察するもので、これによって進化生物学の分野に重要な知見を提供できると確信する。第二に、DNAレベルとタンパク質レベルの実証可能な実験系を導入して、マクロな多様化のメカニズムの解明にアプローチしている点である。タンパク質の機能を実際に観察しながら、具体的にどの部位のどのアミノ酸変異が環境への適応や生物の多様化に関わっているのかを詳細に解析しようとする点も、本研究の重要な特色である。
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