祖先的グリア細胞の分子解剖

• Material Type: 博士論文
• Title: 祖先的グリア細胞の分子解剖
• Author/Editor: Sheloukhova, Larisa
• Author Heading: Sheloukhova, Larisa
• Publication Date: 2022-03-31
• Publication Date (W3CDTF): 2022-03-31
• Alternative Title: Molecular Dissection of Ancestral Glia
• Degree Grantor: Okinawa Institute of Science and Technology Graduate University
• Date Granted: 2022-03-31
• Date Granted (W3CDTF): 2022-03-31
• Dissertation Number: 甲第89号
• Degree Type: Doctor of Philosophy
• Text Language Code: eng
• Target Audience: 一般
• Note (General): Nervous systems of bilaterian animals generally consist of two cell types: neurons and glial cells. Glia participate in almost every process taking place in the nervous system of bilaterians, indicating a crucial role of glial cells in both neurophysiological functions and for the nervous system evolution. Therefore, tracing back the first glia and elucidating its ancestral function is important for understanding the evolutionary sophistications of the nervous system. Histological examinations have not so far revealed any morphological sign of glial cells in Cnidaria, the closest outgroup to Bilateria. This led to the hypothesis that glial cells appeared after the common bilaterian ancestor had branched off from Cnidaria. However, this view has not been well examined at the genetic level. In this work I sought to investigate gliogenic program conservation in non-bilaterian animals, i.e. basal metazoans (Cnidaria, Placozoa, Ctenophora, and Porifera). First, I performed a phylum-wide and genome-wide survey on representative species of bilaterians and basal metazoans to clarify the conserved genetic repertoire required for bilaterian glial development. I found that the glial cells missing (Gcm) is one of the evolutionary conserved glial transcription factors (TF). Second, in Nematostella vectensis, a cnidarian model with highly conserved genetic repertoire required for bilaterian glial development, a homolog of Gcm is expressed in specific neuronal cells. I analyzed the function of Gcm by knocking it down and performing RNA-seq and RT-qPCR analyses. I found that the Gcm knockdown in Nematostella embryos resulted in expression alterations of cell adhesion proteins, GABA and glutamate transporters, ion channels, metabolic and protein modifying enzymes, as well as zinc finger and Ets-related TFs. In addition, Gcm seems to control Notch-Delta signaling, which is one of the crucial neuro-gliogenic pathways in bilaterians. Immunostaining of a Gcm target protein visualized a novel class of cells with flat cell body and no clear neurite process, which were previously classified as neurons as they express neuronal markers (neuropeptides). The major finding of my thesis is that Nematostella Gcm-expressing cells demonstrate characteristics of both neurons and glia, suggesting a dual nature of ancestral cells. This may indicate that the ancestral gliogenic program was intertwined with the neurogenic program and separated later in the animal evolution.
• DOI: 10.15102/1394.00002357; https://doi.org/10.15102/1394.00002357
• Persistent ID (NDL): info:ndljp/pid/13023737; https://dl.ndl.go.jp/pid/13023737
• 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): 2023-10-11T15:41:03+09:00
• Format (IMT): application/pdf
• Access Restrictions: 国立国会図書館内限定公開
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• Periodical Title (URI): http://dx.doi.org/10.15102/1394.00002357; https://oist.repo.nii.ac.jp/records/2614
• 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