Role of discoidins I and II during development of Dictyostelium discoideumD

单克隆抗体提出的碳水化合物结合蛋白（discoidin I和discoidin II）的细胞黏菌，盘基网柄菌discoideum的制备和表征。单克隆抗体1E7特异性结合盘状蛋白I和II。mAbs5C7和3F9仅结合盘状肽I，但它们的结合特异性不同：5C7识别天然形式，3F9识别变性形式。mAb 4B3仅结合变性的盘状蛋白II。mAb 5C7和3G4的结合特异性进一步使用“天然”和尿素凝胶电泳表征。利用这些特异性抗体探针，分别与discoidin I的寡聚体结合的mAbs 5C7和3G4，以及与discoidin I的单体结合的mAbs 3F9，对discoidin I的单体和寡聚体的亚细胞定位进行了免疫细胞化学研究。结果发现，寡聚体识别单克隆抗体分布在多细胞体的网骨藻。盘状体分布于胞浆内，但不分布于多片体。我们推测，discoidin寡聚体识别多层体的特异性结合位点的discoidin寡聚体，其中结合位点后，寡聚体形成暴露。

Monoclonal antibodies raised against carbohydrate-binding proteins (discoidin I and discoidin II) in the cellular slime mold, Dictyostelium discoideum were prepared and characterized. Monoclonal antibody 1E7 bound both discoidins I and II specifically. mAbs5C7 and 3F9 bound only discoidin I but their binding specificities were different:5C7 recognized the native form and 3F9 recognized the denatured form. mAb 4B3 bound only denatured discoidin II.The binding spedificities of mAbs 5C7 and 3G4 further characterized using "native and urea -gel electrophoresis. mAbs 5C7 and 3G4 bound to oligomer of discoidin I and mAbs 3F9 bound to the monomer of discoidin I using these specific antibody probes, we examined the subcellular localization of monomer and oligomer of discoidins immunocytochemically. It was found that oligomer-recognizing mAbs distributed multicellular bodies of Dictyostelium. Discoidin monomer distributed cytoplasms but not multillamelar bodies. We speculate that discoidin oligomer recognize multilamellar bodies by a specific binding site of the discoidin oligomer, of which binding site was exposed after oligomer formation.