2007 Fiscal Year Final Research Report Summary
Molecular genetic approach to understanding the functional architecture of the secondary olfactory neural circuitry
| Project/Area Number |
18300112
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neuroscience in general
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| Research Institution | The Institute of Physical and Chemical Research |
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Principal Investigator |
YOSHIHIRO Yoshihiro The Institute of Physical and Chemical Research, Lab for Neurobiology of Synapse, Leb Head (20220717)
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| Co-Investigator(Kenkyū-buntansha) |
MIYASAKA Nobuhiko RIKEN, Lob for Neurobiology of Synapes, Research Scientist (70332335)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Olfactory system / Neural circuit formation / Zebrafish / Mouse / Transgenic / Chemokine / BIG-2 / Axon guidance |
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| Research Abstract |
(1) Functional architecture of the olfactory neural circuitry revealed in BAC transgenic zebrafish. Using BAC transgenic system, we found the hierarchical regulation of odorant receptor gene choice in the olfactory sensory neurons of the zebrafish. In addition, we demonstrated the axonal convergence to topographically defined glomeruli in the zebrafish olfactory bulb.
(2) A dual role of Cxcl12/Cxcr4 chemokine signaling in the early development of the zebrafish olfactory system. In the zebrafish olfactory system, precursors of olfactory sensory neurons (OSNs) assemble into a compact cluster to form the olfactory placode. Subsequently, OSNs differentiate and extend their axons to the presumptive olfactory bulb with high precision. By using a combination of various molecular genetic techniques, we found that chemokine signaling contributes to both the olfactory placode assembly and the OSN axon pathfinding in zebrafish.
(3) BIG-2 mediates olfactory axon convergence to target glomeruli in th
… More
e mouse olfactory system. Olfactory sensory neurons expressing a given odorant receptor converge axons onto a few topographically fixed glomeruli in the olfactory bulb, leading to establishment of the odor map. Here we report that BIG-2/contactin-4, an axonal glycoprotein belonging to the immunoglobulin superfamily, is expressed in a subpopulation of mouse olfactory sensory neurons. A mosaic pattern of glomerular arrangement is observed with strongly BIG-2-positive, weakly positive, and negative axon terminals in the olfactory bulb, which is overlapping but not identical with those of Kirrel2 and ephrin-A5. There is a close correlation between the BIG-2 expression level and the odorant receptor choice in individual sensory neurons. In BIG-2-deficient mice, olfactory sensory neurons expressing a given odorant receptor frequently innervate multiple glomeruli at ectopic locations. These results suggest that BIG-2 is one of the axon guidance molecules crucial for the formation and maintenance of functional odor map in the olfactory bulb. Less
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Research Products
(75 results)
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[Book] 匂いと香りの科学2007
Author(s)
吉原良浩(分担執筆)
Total Pages
248
Publisher
朝倉書店
Description
「研究成果報告書概要(和文)」より
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