Joint study on cell adhesion molecules in development

Research Project

Project/Area Number	06044176
Research Category	Grant-in-Aid for international Scientific Research
Allocation Type	Single-year Grants
Section	Joint Research
Research Institution	KYUSHU UNIVERSITY
Principal Investigator	NOMURA Kazuya Dept.Biol., Kyushu Univ., Associate professor, 理学部, 助教授 (30150395)
Co-Investigator(Kenkyū-buntansha)	KAI Simons EMBL分子生物学研究所(ドイツ), 細胞生物学部門, 教授 JOHN Gerhart カリフォルニイア大学(米国), バークレー分校細胞分子生物学部門, 教授 KAGEURA Hiroshi Dept.Biol., Fukuoka Univ., Associate professor, 理学部, 助教授 (70194694) SIMONS Kai European Molecular Biology Laboratory, Heidelberg, (Germany) Professor GERHART John Dept.Mol.Cell Biol., Univ.California at Berkeley, (U.S.A.) Professor
Project Period (FY)	1994
Project Status	Completed (Fiscal Year 1994)
Budget Amount *help	¥3,500,000 (Direct Cost: ¥3,500,000) Fiscal Year 1994: ¥3,500,000 (Direct Cost: ¥3,500,000)
Keywords	Xenopus Laevis / XB Cadherin / Antisense Knock Out / Human Blood Group Antigens / Blood Group B Antigen / Glycosphingolipids / Glycoproteins / Cell Adhesion Molecules
Research Abstract	In vertebrate embryogenesis, cell adhesion molecules play fundamental roles in development and morphogenesis. We previously reported that cadherin mediated Ca^<2+> dependent cell-cell adhesion system is the only cell adhesion system functional in early frog embryogenesis. Recently, we found that the function of this Ca^<2+> dependent cell-cell adhesion system is completely disrupted by an antihuman blood group B monoclonal antibody. Fab fragments of the antibody or purified blood group B active substances also disrupted Ca^<2+> dependent cell adhesion, and the inhibition of cadherin-mediated cell adhesion is not due to the steric hindrance caused by the antibody. The blood group B active determinant was detected on glycolipids and on glycoproteins. We determined the complete structure of the blood group B active pentaglycosylceramides found in blastula cells. The glycoepitoe was not found on cadherins. The glycoproteins with blood group B epitopes were partially purified in our laboratory. By measuring resonance energy transfer between two molecules, we showed that the human blood group B active determinants colocalize with E-cadherins in tadpoles, and with XB-cadherins in blastulae. Thus, it is highly possible that human blood type B determinant associates with cadherin and is regulating cadherin functions by forming supramolecular complex with them. To analyze the nature of this interaction in embryogenesis, we prepared dominant negative forms of XB-cadherins and made them expressed in early embryogenesis. The morphogenesis and development of the frog embryos were markedly affected by expressing dominant negative cadherins, and the interactions of blood group B active determinant and cadherins were severely disrupted. We are now analyzing the distribution and function of blood group B active determinants in these embryos. Knocking out of the maternal pool of cadherins by antisense oligonucleotides is also being tried by using newly refined technique.