ABSTRACT

Sialic acids (Sias) are an outermost-situated sugar of glycoproteins and glycolipids to play important roles in various biological phenomena. They are often modified by additional substituents, such as O-acetyl group, to display more than 50 different structures in nature. Of those modified Sia, nothing is known about the occurrence and biological functions of sulfated Sias (SiaSs) in mammals. To elucidate the significance of sialic acid sulfation, we investigated various mammalian-cultured cell lines for the expression of SiaS using the specific antibody 3G9. First, SiaS is expressed in a cell line-dependent and a cell density-dependent manner. Second, in CHO cells, the expression of SiaS is reversibly induced by treatment with the antibiotic G418. Taken together, the expression of SiaS is changed by intrinsic and extrinsic factors in mammalian cells. This is the first demonstration of regulated expression of SiaS.

摘要

唾液酸（Sias）是糖蛋白和糖脂的最外层糖，在各种生物现象中起重要作用。它们通常被其他取代基如O修饰-乙酰基，在自然界中可以显示50多种不同的结构。在那些经过修饰的Sia中，关于硫酸化Sias（SiaSs）在哺乳动物中的发生及其生物学功能的信息一无所知。为了阐明唾液酸硫酸化的重要性，我们使用特异性抗体3G9研究了多种哺乳动物培养的细胞系对SiaS的表达。首先，SiaS以依赖细胞系和依赖细胞密度的方式表达。其次，在CHO细胞中，通过用抗生素G418处理可逆地诱导SiaS的表达。综上所述，SiaS的表达受哺乳动物细胞内在和外在因素的影响而改变。这是SiaS调控表达的首次证明。