Membrane Fusion in Gametes

研究了海洋无脊椎动物配子的三种膜融合系统：顶体反应、精卵融合和皮层小泡的胞吐作用.海星卵冻中的两个信号分子阿里斯和SAP是诱导顶体反应所必需的。它们的结构进行了研究，参考其生物活性。阿里斯的主要糖链具有五糖重复单元[-4Xylb1-3Gala1- 3FucSa 1 - 4Fuca 1 - 3FucSa 1-]_n（FucS：Fuc-4-sulfate）。11个富含谷氨酰胺的由二硫键形成的25个残基环的四肽被鉴定为海星SAP。一种锌金属内蛋白酶参与海鞘精卵融合。这种蛋白酶从精子中纯化并表征。免疫细胞化学法显示该酶定位于精子头部的一定区域.在海星卵母细胞的成熟过程中，皮层小泡改变其胞吐能力和模式，以响应受精。研究了1-甲基腺嘌呤诱导海星卵母细胞成熟过程中皮层小泡的超微结构变化。完全发育的未成熟卵母细胞在皮质中具有细胞角蛋白丝的细胞质网络。异源三聚体G蛋白，这是已知的介导1-甲基腺嘌呤刺激卵母细胞成熟，免疫细胞化学检测的长丝作为周期性的带0.7妈妈长。

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.