Stark Holger, Lührmann Reinhard
Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany.
Annu Rev Biophys Biomol Struct. 2006;35:435-57. doi: 10.1146/annurev.biophys.35.040405.101953.
Splicing is an essential step of gene expression in which introns are removed from pre-mRNA to generate mature mRNA that can be translated by the ribosome. This reaction is catalyzed by a large and dynamic macromolecular RNP complex called the spliceosome. The spliceosome is formed by the stepwise integration of five snRNPs composed of U1, U2, U4, U5, and U6 snRNAs and more than 150 proteins binding sequentially to pre-mRNA. To study the structure of this particularly dynamic RNP machine that undergoes many changes in composition and conformation, single-particle cryo-electron microscopy (cryo-EM) is currently the method of choice. In this review, we present the results of these cryo-EM studies along with some new perspectives on structural and functional aspects of splicing, and we outline the perspectives and limitations of the cryo-EM technique in obtaining structural information about macromolecular complexes, such as the spliceosome, involved in splicing.
剪接是基因表达的一个重要步骤，在此过程中，内含子从前体mRNA中被去除，以产生可被核糖体翻译的成熟mRNA。该反应由一种称为剪接体的大型动态大分子RNP复合物催化。剪接体由五个snRNP逐步组装而成，这五个snRNP由U1、U2、U4、U5和U6 snRNA以及150多种蛋白质组成，它们依次与前体mRNA结合。为了研究这种在组成和构象上经历许多变化的特别动态的RNP机器的结构，单颗粒冷冻电子显微镜（cryo-EM）是目前的首选方法。在这篇综述中，我们展示了这些冷冻电子显微镜研究的结果，以及关于剪接的结构和功能方面的一些新观点，并且我们概述了冷冻电子显微镜技术在获取有关参与剪接的大分子复合物（如剪接体）的结构信息方面的前景和局限性。
