Mimori T, Hinterberger M, Pettersson I, Steitz J A
J Biol Chem. 1984 Jan 10;259(1):560-5.
Autoantibodies directed against the U2 small nuclear ribonucleoprotein (snRNP) have been found in the serum of a patient with scleroderma-polymyositis overlap syndrome. This specificity, called anti-(U2)-RNP, is distinct from all previously described autoantibodies, including those that precipitate related snRNPs: anti-Sm antibodies, which react with the entire set of U1, U2, U4, U5, and U6 snRNPs, and anti-(U1)RNP antibodies, which recognize only U1 snRNPs. From HeLa cell extracts, anti-(U2)RNP immunoprecipitates predominantly one 32P-labeled RNA species, identified as U2 small nuclear RNA, and six [35S]methionine-labeled protein bands, A' (Mr = 32,000), B (Mr = 28,000), D (Mr = 16,000), E (Mr = 13,000), F (Mr = 12,000), and G (Mr = 11,000). Protein blot analysis reveals that the A' protein carries (U2)RNP antigenic determinant(s) and therefore represents a polypeptide unique to the U2 snRNP; the B protein associated with U2 snRNPs may also be unique. Like U1 and the other Sm snRNPs, U2 snRNPs occupy a nuclear, non-nucleolar location and are antigenically conserved from insects to man. An antibody specific for the U2 snRNP will be useful in deciphering the function of this particle.
在一名硬皮病-多肌炎重叠综合征患者的血清中发现了针对U2小核核糖核蛋白（snRNP）的自身抗体。这种特异性，称为抗（U2）-RNP，与所有先前描述的自身抗体不同，包括那些沉淀相关snRNP的抗体：抗Sm抗体，其与整个U1、U2、U4、U5和U6 snRNP组反应，以及抗（U1）RNP抗体，其仅识别U1 snRNP。从HeLa细胞提取物中，抗（U2）RNP免疫沉淀主要一种32P标记的RNA物种，鉴定为U2小核RNA，以及六条[35S]甲硫氨酸标记的蛋白带，A'（Mr = 32,000）、B（Mr = 28,000）、D（Mr = 16,000）、E（Mr = 13,000）、F（Mr = 12,000）和G（Mr = 11,000）。蛋白质印迹分析表明，A'蛋白携带（U2）RNP抗原决定簇，因此代表U2 snRNP特有的一种多肽；与U2 snRNP相关的B蛋白也可能是独特的。与U1和其他Sm snRNP一样，U2 snRNP位于细胞核、非核仁位置，并且从昆虫到人类在抗原上是保守的。一种针对U2 snRNP的特异性抗体将有助于解读该颗粒的功能。
