2007 Fiscal Year Final Research Report Summary
Role of Sixl in development of olfactory epithelium
| Project/Area Number |
18590172
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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 |
General anatomy (including Histology/Embryology)
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| Research Institution | Jichi Medical University |
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Principal Investigator |
IKEDA Keiko Jichi Medical University, Dept. Medicine, Associate Professor (10265241)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Six1 / Olfactory epithelium / pioneer neuron / aoon / Hesl / Neurogenin1 / Knockout mice / placode |
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| Research Abstract |
The olfactory epithelium (OE) is derived from the olfactory placode (OP) during mouse development. At embryonic day (E) 10.0-E10.5, "early neurogenesis" occurs in the OE, which includes production of pioneer neurons that emigrate out of the OE and other early-differentiated neurons. Around E12.5, the OE becomes organized into mature pseudostratified epithelium and shows "established neurogenesis," in which olfactory receptor neurons (ORNs) are differentiated from basal progenitors. Little is known about the molecular pathway of early neurogenesis. The homeodomain protein Six1 is expressed in all OP cells and neurogenic precursors in the OE. Here we show that early neurogenesis is severely disturbed despite the unaltered expression of Mashl at E10.5 in the Six1-deficient mice (Six1^<-/->). Expression levels of neurogenin1 (Ngn1) and NeuroD are reduced and those of Hes1 and Hes5 are augmented in the OE of Six1^<-/-> at E10.5. Pioneer neurons and cellular aggregates, which are derived from the OP/OE and situated in the mesenchyme between the OE and forebrain, are completely absent in Six1^<-/->. Moreover, ORN axons and the gonadotropin-releasing hormone-positive neurons fail to extend and migrate to the forebrain, respectively. Our study indicates that Six1 plays critical roles in early neurogenesis by regulating Ngn1, NeuroD, Hes1, and Hes5. Currently, to analyze gene regulatory network essential for production of pioneer neurons more detail, we are planning to do microarray analysis of the relative gene expression profiles in E9.5 wild-type v.s. Six1^<-/-> OP identified candidate genes for differentiation of pioneer neurons.
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[Presentation] Development of mouse olfactory epithelium2006
Author(s)
Ikeda, K., Ando, Z., Ookawara, S., Kageyama, R., Kawakami, K
Organizer
20th IUBMB International Congress of Biochemistry and Molecular Biology 11th FAOBMB Congress
Place of Presentation
Kyoto
Year and Date
20060618-23
Description
「研究成果報告書概要(欧文)」より
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