| Project/Area Number |
08044210
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
NOMURA Kazuya Kyushu University, Faculty of Science, Department of Biology, Associate Professor, 理学部, 助教授 (30150395)
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| Co-Investigator(Kenkyū-buntansha) |
GUMBINER Bar スローンケタリング記念癌センター, 細胞生化学・生物物理学部門, 教授
GERHART John カリフォルニア大学バークレー分校, 分子細胞生物学科, 教授
TAJIMA Tatsuya Kumamoto University, Faculty of Science, Research Associate, 理学部, 助手 (00216962)
YUGE Masahiro Fukuoka Women's University, Faculty of Environmental Science, Lecturer, 環境理学部, 講師 (80220523)
KAGEURA Hiroshi Fukuoka University, Faculty of Science, Associate Proffessor, 理学部, 助教授 (70194694)
JOHN C Gerhart University of California at Berkeley, Department of Molecular & Cell Biology, Pr
BARRY M Gumbiner Memorial Sloan-Kettering Cancer Center, Cellular Biochemistry and Biophysics Pro
BRIEHER Will スローンケタリング記念癌センター, 細胞生化学・生物物理学部門, 助手
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| Project Period (FY) |
1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1996: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Xenopus laevis / cortical granule / determinant / XB-cadherin / cell adhesion / induction / lectin / GPI-anchor |
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| Research Abstract |
In this study, we examined the roles of cell-cell adhesion in inductive processes in development. Previously, Dr.Yuge discovered that the cytoplasm of 16-cell stage dorsal blastomeres of frog embryos has dorsal determinant activity. Prof.Gumbiner and Dr.Brieher clarified the importance of beta-catenin in frog dorsoventral axis formation, and Prof.Gerhart's group showed the importance of beta-catenin as dorsal determinant. Dr.Yuge examined whether his dorsal determinants are beta-catenins or not, and found that his determinants are different from beta-catenins. His determinants and beta-catenins are localized in the cortex of the cleaving embryos, and Dr.Kageura showed that grafting of cortex causes secondary axis formation at a very high frequency. Cadherins that are Ca^<2+> dependent cell-cell adhesion molecules seem to be controlling axis induction indirectly by absorbing free beta-catenins. To clarify the roles of cadherins in induction, Tajima cloned the XB cadherin cDNA and made two different dominant negative gene constructs. Gastrulation of frog embryos was affected by knocking out of cadherin gene products while cell-cell adhesion is least affected. This strongly suggests that other adhesion molecules are active in early embyogenesis. Nomura identified novel human blood group B active glycosylphosphatidyl inositol anchored lectin (Pi-lectin), which are essential for Ca^<2+> dependent cell-cell adhesion. The proteins are membrane anchored homologues of soluble frog cortical granule lectins which are localized in cortex of the unfertilized egg and act for blocking of polyspermy at fertilization. Thus newly discovered Pi-lectin seems to be playing major roles in early embryonic adhesion, and their localization strongly suggests that it is interacting with dorsal axis determinants. The knocking out of the Pi-lectin is being carried out in our laboratory.
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