2005 Fiscal Year Final Research Report Summary
Molecular mechanism which control proliferation and differentitation of neural stem cells.
| Project/Area Number |
16606004
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
幹細胞生物学
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| Research Institution | Keio University |
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Principal Investigator |
NAKAO Keiko Keio University, School of Medicine, Instructor, 医学部, 助手 (70338185)
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| Co-Investigator(Kenkyū-buntansha) |
OKANO Hideyuki Keio University, School of Medicine, Professor, 医学部, 教授 (60160694)
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| Project Period (FY) |
2004 – 2005
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| Keywords | neuroepithelial stem cells / Live imaging / endocytosis / Drosophila / aPKC / adherens junction / Symmetric / asymmetric division / Notch signaling |
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| Research Abstract |
Drosophila optic neurons are derived from the outer proliferating center (OPC) of larval brain. It was suggested that OPC contains neuroepithelium core (NE), which was distinctive from outside neuroblasts (Nbs). NE proliferates by symmetric division to be converted into the spherical Nbs from the edge of the NE and then divide asymmetrically to give rise to neural precursors. To clarify the underlying mechanism of the maintenance of the symmetric division from the asymmetric division, we have visualized the cell-dividing image of NE and Nbs by time-lapse observation with several GFP fusion proteins. NE and Nb cells preferred the dividing axes parallel and orthogonal to the apical surface plane, respectively. We have also investigated the involvement of molecules that interact with adherens junctions (AJs), assuming that AJs might inhibit conversion and consequent asymmetric division of newborn Nbs. It had been found that dissociation between AJ and centrosome had been implicated in loss of proper control of cell-dividing orientation. We observed that the apical accumulation of E-cadherin, aPKC,Baz and Dlt had been disappeared within some step of conversion from symmetric proliferating NE to Nbs. Loss of aPKC caused severe defect on formation of apico-basal polarity of OPC. These results suggest that AJ and/or apico-basal polarization of cell cortex play a key role to restrain the exit from symmetric division and consequent asymmetric division of Nbs and symmetric dividing. Therefore, we conclude that NE cells are neural stem cells in larval brain.
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