1994 Fiscal Year Final Research Report Summary
Membrane Fusion in Gametes
| Project/Area Number |
05044125
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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 | Tokyo Institute of Technology |
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Principal Investigator |
HOSHI Motonori Tokyo Institute of Technology, 生命理工学部, 教授 (20012411)
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| Co-Investigator(Kenkyū-buntansha) |
DARSZON Alberto National Autonomous University of Mexico, 生物工学研究所, 教授
LONGO Frank j. Iowa University Medical School, 医学部, 教授
CHIBA Kazuyoshi Tokyo Institute of Technology, 生命理工学部, 助手 (70222130)
MATSUMOTO Midori Tokyo Institute of Technology, 生命理工学部, 助手 (00211574)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Membrane Fusion / Fertilization / Acrosome Reaction / Sperm Activating Pepetide / Sulfated Saccharide Chain / Metalloendoprotease / Cortical Vesicle / Trimeric G Protein |
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| Research Abstract |
Three membrane fusion systems in the gametes of marine invertebrates were studied ; the acrosome reaction, sperm-egg fusion and exocytosis of cortical vesicles.
1. Two signal moleules in starfish egg jelly, namely ARIS and SAP,are essential for the induction of acrosome reaction. Their structures were studied with reference to their biological activities. Major saccharide chains of ARIS had a repeating unit of pentasaccharide, [-4Xylb1-3Gala1-3FucSa1-4Fuca1-3FucSa1-]_n (FucS : Fuc-4-sulfate). Eleven glutamine-rich tetracontapeptides with a 25-residue ring formed by a disulfide linkage were identified as starfish SAPs.
2. A zinc-metalloendoprotese is involved in the sperm-egg fusion of the ascidian, Ciona intestinalis. Such protease was purified from the sperm and characterized. The enzyme was immunocytochemically located in a certain region of sperm head.
3. During maturation of starfish oocytes, cortical vesicles change their exocytotic capacity and pattern in response to fertilization. Ultrastructural changes of cortical vesicles in starfish oocytes were studied in relation to the oocyte maturation induced by 1-methyladenine. Fully-grown immature oocytes have a cytoplasmic network of cytokeratin filaments in the cortex. Heterotrimeric G protein, which is known to mediate 1-methyladenine stimulation of oocyte maturation, was immunocytochemically detected on the filaments as periodical bands of 0.7 mum long.
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