2006 Fiscal Year Final Research Report Summary
Molecular Mechanism of sperm-egg membrane fusion in fertilization
| Project/Area Number |
16390480
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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 |
Obstetrics and gynecology
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| Research Institution | National Center for Child Health and Development |
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Principal Investigator |
MIYADO Kenji National Center for Child Health and Development, Department of Reproductive Biology, Division Chief, 生殖医療研究部 生殖細胞機能研究室, 室長 (60324844)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Fertilization / Membrane Fusion / CD9 / CD81 / Microvilli / Tubulin / Tetraspanin / Imaging |
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| Research Abstract |
Fertilization is an essential process that naturally produces a cell capable for developing into a new individual. However, a molecular mechanism that underlying membrane interaction of sperm and egg still remains a mystery in mammals. CD9, a tetraspan-membrane protein (tetraspanin), expressed in a wide variety of cells, is reported to function in many cellular events. CD9 associates with other tetraspanins and some kinds of membrane proteins to form complexes at the plasma membrane. In fertilization, CD9 is required for sperm-egg fusion, and also implicated in other fusion events. When inseminated, eggs from CD9-/-females bound sperm normally, but were greatly impaired in fusion with sperm, but not developmental processes. Since CD9 can associate with integrins, models of fertilization have posited that CD9 acts in association with alpha6betal in fusion. However, analyses of deficient eggs have sublated that integrins are essential for sperm-egg fusion. A new model in which CD9 acts by itself, or interacts with egg protein(s) other than integrins, to function in sperm-egg fusion, was proposed. CD9 was exclusively localized to microvilli, not concentrated of actin-filaments. Electron microscopy also revealed that CD9-/-eggs had a severe defect in microvilli formation. When a vector, expressing EGFP- tagged CD9 under oocyte-specific promoter, was transferred into CD9-/-females, both gametes fusion and microvilli formation were restored. Microvilli, visualized by EGFP-CD9, was vitally monitored and defined to function in gametes fusion. These results indicate that CD9 is a key element for the formation of microvilli required for sperm-egg fusion.
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[Journal Article] Possible involvement of CD81 in acrosome reaction of sperm in mice.2007
Author(s)
Tanigawa M, Miyamoto K, Kobayashi S, Sato M, Akutsu H, Okabe M, Mekada E, Sakakibara K, Miyado M, Umezawa A, Miyado K.
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Journal Title
Mol Reprod Dev. (in press)
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Hyaline cartilage formation and enchondral ossification modeled with KUM5 and OP9 chondroblasts.2007
Author(s)
Sugiki T, Uyama T, Toyoda M, Morioka H, Kume S, Miyado K, Matsumoto K, Saito H, Tsumaki N, Takahashi Y, Toyama Y, Umezawa A.
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Journal Title
J Cell Biochem. 100(5)
Pages: 1240-54
Description
「研究成果報告書概要(欧文)」より
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