小核核糖核蛋白颗粒U1的结构：用核糖核蛋白抗原A和70K鉴定两个结构突出物。
Structure of the small nuclear RNP particle U1: identification of the two structural protuberances with RNP-antigens A and 70K.
作者信息
Kastner B, Kornstädt U, Bach M, Lührmann R
机构信息
Institut für Molekularbiologie und Tumorforschung, Marburg, Germany.
出版信息
J Cell Biol. 1992 Feb;116(4):839-49. doi: 10.1083/jcb.116.4.839.
We have investigated the structure of the small nuclear RNP (snRNP) U1 by combining EM of complete and partially protein-deficient particles with immunoelectron microscopy employing mAbs against known components of the U1 snRNP. It was found that the two main protuberances of this particle can be identified with the U1-specific proteins A and 70K. The 70K protuberance is the one lying closer to the 5' terminus of the snRNA, as identified by its 5'-terminal m3G cap. The round-shaped main body of U1 snRNP represents its core RNP domain containing the common snRNP proteins. Functional implications of these results are discussed. Our results may also point to the physical basis for the production of autoantibodies directed against specific groups of snRNP proteins. The physical grouping of the common proteins (Sm epitopes) and the specific proteins (RNP epitopes) could result in one or the other being presented to the immune system as is the case in patients suffering from SLE or MCTD, respectively.
我们通过将完整的和部分缺乏蛋白质的颗粒的电子显微镜（EM）与使用针对U1 snRNP已知成分的单克隆抗体（mAb）的免疫电子显微镜相结合，研究了小核核糖核蛋白（snRNP）U1的结构。结果发现，该颗粒的两个主要突出部分可分别与U1特异性蛋白A和70K相对应。70K突出部分是更靠近snRNA 5'末端的那个，这是通过其5'-末端的m3G帽确定的。U1 snRNP的圆形主体代表其核心RNP结构域，包含常见的snRNP蛋白。讨论了这些结果的功能意义。我们的结果也可能指出针对特定snRNP蛋白组产生自身抗体的物理基础。常见蛋白（Sm表位）和特定蛋白（RNP表位）的物理分组可能导致其中之一分别如系统性红斑狼疮（SLE）或混合性结缔组织病（MCTD）患者那样呈现给免疫系统。
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