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Studies on control of mobile retrotransposons in Arabidopsis
https://ir.soken.ac.jp/records/3594
https://ir.soken.ac.jp/records/35944510d269-8c0e-4b95-bc86-b96f0597888f
| 名前 / ファイル | ライセンス | アクション |
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要旨・審査要旨 (281.7 kB)
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| Item type | 学位論文 / Thesis or Dissertation(1) | |||||||
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| 公開日 | 2013-06-14 | |||||||
| タイトル | ||||||||
| タイトル | Studies on control of mobile retrotransposons in Arabidopsis | |||||||
| タイトル | ||||||||
| タイトル | Studies on control of mobile retrotransposons in Arabidopsis | |||||||
| 言語 | en | |||||||
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| 言語 | eng | |||||||
| 資源タイプ | ||||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_46ec | |||||||
| 資源タイプ | thesis | |||||||
| 著者名 |
塚原, 小百合
× 塚原, 小百合
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| フリガナ |
ツカハラ, サユリ
× ツカハラ, サユリ
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| 著者 |
TSUKAHARA, Sayuri
× TSUKAHARA, Sayuri
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| 学位授与機関 | ||||||||
| 学位授与機関名 | 総合研究大学院大学 | |||||||
| 学位名 | ||||||||
| 学位名 | 博士（理学） | |||||||
| 学位記番号 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | 総研大甲第1560号 | |||||||
| 研究科 | ||||||||
| 値 | 生命科学研究科 | |||||||
| 専攻 | ||||||||
| 値 | 18 遺伝学専攻 | |||||||
| 学位授与年月日 | ||||||||
| 学位授与年月日 | 2012-09-28 | |||||||
| 学位授与年度 | ||||||||
| 値 | 2012 | |||||||
| 要旨 | ||||||||
| 内容記述タイプ | Other | |||||||
| 内容記述 | Retrotransposons are major components of the eukaryotic genome. They have proliferated in the genome during evolution through their copy-and-past type transposition. However, in the current genome, most of them are inactivated by degeneration or silencing mechanism of hosts. In the model plant Arabidopsis thaliana, most of retrotransposons are located in pericentromeric region where epigenetic marks such as DNA methylation and histone H3 lysine 9 methylation (H3K9me) are enriched, that are associated with inactive state of chromatin, heterochromatin. In Part 1, I identified a mobile endogenous LTR (long terminal repeat) retrotransposon, ATGP3 in ddm1 (decrease in DNA methylation 1) mutant of A. thaliana, where DNA methylation is globally decreased. ATGP3 is transcribed and it retrotransposed in ddm1, while it is inactive in wild-type. ATGP3 is also mobilized in the double mutant of DNA methyltransferase for CG sites, MET1 (MTHYLTRANSFERASE 1) and for non-CG sites, CMT3 (CHROMOMETHYLASE 3), suggesting that ATGP3 is repressed by both CG and non-CG methylation. ATGP3 was firstly identified as a mobile endogenous LTR retrotransposon in A. thaliana. Distribution of the retrotransposons in the genome is not uniform. Most of them are located in pericentromeric region. However, it is not known how retrotransposons are accumulated in pericentromeric region. There are two hypotheses for the biased distribution. One is that retrotransposon insertions in genic region have been eliminated by natural selection and they have remained in gene-poor heterochromatic region. The other is that retrotransposons preferentially integrate into gene-poor region. However, mobile retrotransposon with targeted integration into such region has not been identified in plants. In Part 2, I investigated the second hypothesis using another retrotransposon family, COPIA93. COPIA93 family is one of the retrotransposon families mobilized in ddm1 mutant of A. thaliana. COPIA93 related elements are abundant in A. lyrata, which is closely related species to A. thaliana, and their sequences are very similar to each other, suggesting their recent amplification in A. lyrata. In addition, most of the copies of COPIA93 in A. lyrata are located in centromeric repeats, implying that they specifically integrate into centromeric repeats. In order to examine insertion specificity of their de novo integrations, I cloned and introduced one of the COPIA93 family retrotransposon in A. lyrata, which we named Tal1, into A. thaliana. Introduced Tal1 was transcribed and retrotransposed in A. thaliana. Surprisingly, Tal1 exclusively integrated into centromeric repeats, suggesting that Tal1 has integration specificity into centromeric region. Tal1 provides us useful experimental system to investigate evolutionary dynamics of retrotransposon. |
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| 値 | 有 | |||||||
