被嚢動物のゲノムに水平転移したグリコシルヒドラーゼファミリー６遺伝子の研究

• Material Type: 博士論文
• Title: 被嚢動物のゲノムに水平転移したグリコシルヒドラーゼファミリー６遺伝子の研究
• Author/Editor: Li, Kun-Lung
• Author Heading: Li, Kun-Lung
• Publication Date: 2021-09-30
• Publication Date (W3CDTF): 2021-09-30
• Alternative Title: A Study of Horizontally Transferred Glycosyl Hydrolase Family 6 Genes in Tunicate Genomes
• Degree grantor/type: Okinawa Institute of Science and Technology Graduate University
• Date Granted: 2021-09-30
• Date Granted (W3CDTF): 2021-09-30
• Dissertation Number: 甲第78号
• Degree Type: Doctor of Philosophy
• Conferring No. (Dissertation): 甲第78号
• Text Language Code: eng
• Target Audience: 一般
• Note (General): Tunicates are the closest extant relatives of vertebrates. Tunicates produce cellulosecontaining tunic and exhibit very characteristic lifestyles among animals. Their unique ability to synthesize cellulose results from a horizontally transferred cellulose synthase gene (CesA). Interestingly, a Glycosyl Hydrolase Family 6 (GH6) hydrolase-like domain exists at the C-terminus of tunicate CesA but not in cellulose synthases of other organisms. This led to the identification of another independent GH6-encoding gene, GH6-1, in tunicate genomes. These GH6-encoding genes exist exclusively in tunicates within the animal kingdom. The existence of GH6-encoding genes and the combination of GH6 and cellulose synthase domains raised the question of the evolutionary origin and function of GH6s in tunicates. To answer these questions, I first examined the phylogenetic relationship of GH6- encoding genes by comparing their sequence signatures. Tunicate CesA and GH6-1 genes represent two independent orthologous groups, but the origin of these genes before a horizontal transfer event could not be ascertained. Secondly, I examined the expression of tunicate CesA and GH6-1 genes in Ciona intestinalis type A, a model ascidian tunicate. The gene expression in embryos at early developmental stages was examined by quantitative reverse transcription PCR and in situ hybridization. Obvious expression of both CesA and GH6-1 were found at embryonic stages of Ciona embryo at epidermis. The observed expression profiles were also compared with a set of single-cell transcriptome data provided by our collaborators. Embryonic cells of late tailbud stage I showed that both GH6-1- and CesA-expressing cells are mostly in cell clusters of epidermal identity. Localized signal in the reporter assay also suggest the existence of specific enhancers upstream to Ciona GH6- 1 gene. Finally, I used genome-editing technique to generate GH6-1 knockout larvae of C. intestinalis type A and observed that affected embryos show perturbed papillae formation and metamorphosis. My study showed that GH6-1, a gene very likely originated from horizontal gene transfer, is recruited to function in ascidian early development. This observation would help to address how tunicates evolved by obtaining their unique anatomy and ecology.
• DOI: 10.15102/1394.00002095; https://doi.org/10.15102/1394.00002095
• Persistent ID (NDL): info:ndljp/pid/12297215; https://dl.ndl.go.jp/pid/12297215
• Collection: 障害者向け資料
• Collection (Materials For Handicapped People:1): テキストデータ
• Collection (particular): 国立国会図書館デジタルコレクション > デジタル化資料 > 博士論文; https://dl.ndl.go.jp/collections/A00014
• Acquisition Basis: 博士論文（自動収集）
• Date Accepted (W3CDTF): 2022-06-05T18:01:14+09:00
• Date Created (W3CDTF): 2021-10-14
• Format (IMT): application/pdf
• Access Restrictions: 国立国会図書館内限定公開
• Service for the Digitized Contents Transmission Service: 図書館・個人送信対象外
• Availability of remote photoduplication service: 可
• Periodical Title (URI): http://dx.doi.org/10.15102/1394.00002095; https://oist.repo.nii.ac.jp/records/2325
• Data Provider (Database): 国立国会図書館 : 国立国会図書館デジタルコレクション; https://dl.ndl.go.jp

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2023-10-11 再収集

2023-10-11 再収集