Okano Y, Medsger T A
Department of Medicine, University of Pittsburgh School of Medicine, PA 15261.
J Immunol. 1991 Jan 15;146(2):535-42.
We found serum autoantibodies directed against the proteins binding exclusively to U4/U6 of Sm small nuclear ribonucleoprotein particle (snRNP) in serum from a patient (MaS) with systemic sclerosis. Their specificity, called anti-MaS, is distinct from that of known antibodies against U snRNP. The U4 and U6 small nuclear RNA from a 32P-labeled HeLa cell extract and five proteins with Mr 150,000, 120,000, 80,000, 36,000, and 34,000, in addition to Sm core proteins (B, B', D, E, F, and G) from an [35S] methionine-labeled extract, were immunoprecipitated by anti-MaS in isotonic solution. However, the Sm core proteins and U4 and U6 small nuclear RNA were separated from the protein-A-Sepharose facilitated MaS immunoprecipitate by incubation in a solution containing 500 mM NaCl. In immunoblots, anti-MaS antibodies reacted with one protein of Mr 150,000 from a HeLa cell nuclear extract that was fractionated by SDS-PAGE and transferred to a nitrocellulose sheet. The monospecific immunoaffinity purified antibody eluted from the immunoblot band immunoprecipitated U4 and U6 small nuclear RNA and reblotted the protein with Mr 150,000. These data indicate that anti-MaS antibodies recognize at least one antigenic protein that binds exclusively to the U4/U6 snRNP.
我们在一名系统性硬化症患者（MaS）的血清中发现了针对仅与Sm小核核糖核蛋白颗粒（snRNP）的U4/U6结合的蛋白质的血清自身抗体。它们的特异性称为抗MaS，与已知的抗U snRNP抗体不同。来自32P标记的HeLa细胞提取物的U4和U6小核RNA以及除了来自[35S]甲硫氨酸标记提取物的Sm核心蛋白（B、B'、D、E、F和G）之外的5种分子量分别为150,000、120,000、80,000、36,000和34,000的蛋白质，在等渗溶液中被抗MaS免疫沉淀。然而，通过在含有500 mM NaCl的溶液中孵育，Sm核心蛋白以及U4和U6小核RNA与蛋白A-琼脂糖促进的MaS免疫沉淀物分离。在免疫印迹中，抗MaS抗体与经SDS-PAGE分离并转移到硝酸纤维素膜上的HeLa细胞核提取物中的一种分子量为150,000的蛋白质发生反应。从免疫印迹条带洗脱的单特异性免疫亲和纯化抗体免疫沉淀了U4和U6小核RNA，并重新印迹了分子量为150,000的蛋白质。这些数据表明抗MaS抗体识别至少一种仅与U4/U6 snRNP结合的抗原性蛋白质。
