Sperm Receptor of Bovine Egg Surface Zona Pellucida

（1997）1：牛精子受体通过体外竞争试验被证明参与带型糖蛋白的碳水化合物部分。2：竞争分析还发现，牛精子主要与高甘露糖型碳水化合物链Man_5GlcNAc_2结合，这是牛带蛋白中主要的中性n链。有报道称，小鼠精子与ZP3蛋白o链非还原端的β -半乳糖残基结合，而猪精子与ZPB蛋白n链非还原端的β -半乳糖残基结合。我们关于牛精子受体的研究结果有助于阐明物种特异性精子与卵子结合的机制。3：为了得到o链，对带蛋白在不同条件下进行碱处理。然而，活性无法测量，因为在任何条件下，n链也会部分地与o链一起裂解。（1998）1：受体活性碳水化合物链被证明存在于ZPB蛋白中。目前尚不清楚ZPA中是否存在活性链，因为HPLC得到的ZPA中有杂聚物被污染，我们正在尝试对ZPA进行纯化。2 .用于确定ZPB中受体活性碳链定位的ZPB的大规模制备也在进行中。3：研究表明，受体活性链Man_5GlcNAc_2对体外受精（IVF）有抑制作用，其衍生物Man_3GlcNAc_2、ManG1cNAc_2和α -甲基甘露糖苷对体外受精（IVF）也有较弱的抑制作用，表明甘露糖残基在牛体外受精中的重要作用。用唾液酸酶处理未受精卵后，与卵子结合的精子数量减少到50%左右，这表明唾液酸在牛精子与卵子的结合中也起作用。

(1997)1 : Bovine sperm receptor was shown to be involved In the carbohydrate moieties of zona glyciproteins by an in vitro competition assay. 2 : Competition assay also revealed that bovine sperm mainly bind to a high-mannnose type carbohydrate chain, Man_5GlcNAc_2 which is major neutral N-linked chain found in bovine zona proteins. It has been reported that mouse sperm bind to beta-galactosyl residues at the non-reducing ends of O-linked chain of ZP3 protein, while porcine sperm to beta-galactosyl residues at the non-reducing ends of N-linked chains of ZPB.Our results on the bovine sperm receptors contribute much to the elucidation of the mechanism of species-specific sperm-egg binding. 3 : In order to obtain O-linked chains, the zona proteins were treated with alkali under various conditions. The activities, however, could not be measured, since N-linked chains were also cleaved partly together with O-linked chains under any conditions.(1998)1 : The receptor active carbohydrate chain was shown to be present in ZPB protein. It is unclear whether the active chain is present in ZPA, since heteropolymers were shown to be contaminated in ZPA obtained by HPLC, We are trying to purify ZPA.2 : Large scale preparation of ZPB for determination of the localization of receptor active carbohydrate chain in ZPB is also In progress. 3 : It was shown that the receptor active chain, Man_5GlcNAc_2, inhibits bovine in vitro fertilization (IVF) and its derivatives Man_3GlcNAc_2, ManG1cNAc_2, and alpha-methylmannoside also weakly inhibit IVF, indicating the essential role of mannose residue(s) at the non-reducing ends in bovine IVF.4 : Treatment of the unfertilized eggs with sialidase reduced the number of binding sperm to the eggs to about 50%, suggesting that sialic acids also play a role in the bovine sperm binding to the eggs.