{"created":"2021-03-01T06:09:10.150808+00:00","id":5317,"links":{},"metadata":{"_buckets":{"deposit":"76509e7c-476b-45f1-9260-d028159bfab2"},"_deposit":{"id":"5317","owners":[],"pid":{"revision_id":0,"type":"depid","value":"5317"},"status":"published"},"_oai":{"id":"oai:niigata-u.repo.nii.ac.jp:00005317","sets":["453:455","468:563:564"]},"item_6_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"イネにおけるＤＮＡメチル化および脱メチル化を介したエピジェネティックなゲノム制御機構の研究"}]},"item_6_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2012-09-20","bibliographicIssueDateType":"Issued"},"bibliographicPageEnd":"157","bibliographicPageStart":"1","bibliographic_titles":[{}]}]},"item_6_date_granted_51":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2012-09-20"}]},"item_6_degree_grantor_49":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_name":"新潟大学"}]}]},"item_6_degree_name_48":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（農学）"}]},"item_6_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"In this thesis, using HR-promoted GT, identical mutations for the rice ROS1a gene encoding a putative cytosine DNA demethylase and for the rice DDM1a/DDM1b genes encoding SWI2/SNF2 chromatin remodeling factors were reproducibly generated. Obtained knock-in/knock-out mutants have shown that proper cytosine demethylation is indispensable in order to facilitate normal developmental processes in rice life cycle, and also that proper cytosine methylation is necessary for protection of rice genome from undesired events, such as potentially harmful reactivation of TEs. Chapter 1 Genes that promote DNA methylation and demethylation in plants have been characterized mainly in Arabidopsis. Arabidopsis DNA demethylation is mediated by bifunctional DNA enzymes with glycosylase activity that removes 5-methylcytosine and lyase activity that nicks the double-stranded DNA at the abasic site. Homologous recombination-promoted knock-in targeting of the ROS1a gene, the longest of six putative DNA demethylase genes in the rice genome, could repeatedly disrupt ROS1a in primary (T_0) transgenic plants by fusing its endogenous promoter with the GUS reporter gene in the heterozygous condition. These T_0 plants exhibited no overt morphological phenotypes during their vegetative phase, and GUS staining showed ROS1a expression in pollen, unfertilized ovules, and meristematic cells. Interestingly, neither the maternal nor the paternal knock-in null allele, ros1a-GUS1, was detected in the progeny; such an intransmittable null mutation would be difficult to isolate by conventional mutagenesis techniques that usually identify and isolate mutants in the progeny population. Even in the presence of the wild-type paternal ROS1a allele, the maternal ros1a-GUS1 allele caused failure of early stage endosperm development resulting in incomplete embryo development, with embryogenesis producing irregular but viable embryos that could not complete seed dormancy, implying nonequivalent maternal and paternal contribution of ROS1 a in endosperm development. The paternal ros1a-GUS1 allele could not be transmitted to progeny, presumably because of a male gametophytic defect(s) prior to fertilization. Thus, ROS1a must be indispensable in both male and female gametophytes, in which DNA demethylation must play important roles. Chapter 2 DNA methylation plays important roles in regulating gene expression. Using homologous recombination-promoted knock-out targeting, an identical mutation for each of the rice DDM1a and DDM1b genes encoding putative SWI2/SNF2-like chromatin remodeling ATPases were reproducibly generated. No effect of OsDDM1a disruption on cytosine methylation was observed at any repetitive sequences investigated. In contrast, OsDDM1b disruption caused decreased cytosine methylation in repetitive sequences. Subsequently generated OsDDM1a and OsDDM1b double disruptant mutants exhibited drastic reduction of cytosine methylation indicating the different degree of contribution and the functional redundancy in certain extent between OsDDM1 a and OsDDM1 b. Double disruption derepressed the transcription of several transposable elements suggesting an essential role for OsDDM1s on epigenetic regulation of repetitive sequences that comprise a large component of rice genome and have contributed to large-scale genome insertions, rearrangements and allelic diversification during its evolution.","subitem_description_type":"Abstract"}]},"item_6_description_5":{"attribute_name":"内容記述","attribute_value_mlt":[{"subitem_description":"学位の種類: 博士（農学）. 報告番号: 甲第3706号. 学位記番号: 新大院博（農）甲第119号. 学位授与年月日: 平成24年9月20日","subitem_description_type":"Other"},{"subitem_description":"巻末の参考論文は著作権上の理由により省略","subitem_description_type":"Other"}]},"item_6_description_53":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_description":"新大院博（農）甲第119号","subitem_description_type":"Other"}]},"item_6_dissertation_number_52":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"13101A3706"}]},"item_6_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"50087","nameIdentifierScheme":"WEKO"}],"names":[{"name":"小野, 明美"}]}]},"item_6_publisher_7":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"新潟大学"}]},"item_6_select_19":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"ETD"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Ono, Akemi"}],"nameIdentifiers":[{"nameIdentifier":"50086","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-08-05"}],"displaytype":"detail","filename":"D_S_N_K119.pdf","filesize":[{"value":"14.4 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"本文","url":"https://niigata-u.repo.nii.ac.jp/record/5317/files/D_S_N_K119.pdf"},"version_id":"c8e721ef-7d96-45c9-99cf-a67eb5f53740"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"thesis","resourceuri":"http://purl.org/coar/resource_type/c_46ec"}]},"item_title":"Studies on DNA Methylation and Demethylation-mediated Epigenetic GenomeRegulation in Rice","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Studies on DNA Methylation and Demethylation-mediated Epigenetic GenomeRegulation in Rice"},{"subitem_title":"Studies on DNA Methylation and Demethylation-mediated Epigenetic GenomeRegulation in Rice","subitem_title_language":"en"}]},"item_type_id":"6","owner":"1","path":["455","564"],"pubdate":{"attribute_name":"公開日","attribute_value":"2014-03-25"},"publish_date":"2014-03-25","publish_status":"0","recid":"5317","relation_version_is_last":true,"title":["Studies on DNA Methylation and Demethylation-mediated Epigenetic GenomeRegulation in Rice"],"weko_creator_id":"1","weko_shared_id":2},"updated":"2022-12-15T03:38:18.439670+00:00"}