Localization of Prp8, Brr2, Snu114 and U4/U6 proteins in the yeast tri-snRNP by electron microscopy
Localization of Prp8, Brr2, Snu114 and U4/U6 proteins in the yeast tri-snRNP by electron microscopy
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DOI：
10.1038/nsmb.1506
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发表时间：
2008-11-01
影响因子：
16.8
通讯作者：
Luehrmann, Reinhard
中科院分区：
文献类型：
--
作者：
Haecker, Irina;Sander, Bjoern;Luehrmann, Reinhard
U4/U6-U 5三小核核糖核蛋白（snRNP）是一种主要的、进化上高度保守的剪接体亚基。其U4/U6 snRNA双链体的解旋是剪接体激活的中心事件，其需要三-snRNP的U 5部分的几种组分，包括RNA解旋酶Brr 2、Prp 8和GTdR Snu 114。在这里，我们报告的EM投影结构的酿酒酵母tri-snRNP。其示出了包括在其中心部分彼此接触的三个挤出域的模块化组织。我们已经通过EM可视化了基因标记的tri-snRNP蛋白，并在这里显示U4/U6 snRNP形成了一个称为臂的结构域。相反，与臂相邻的单独头部结构域含有Brr 2，而Prp 8和GTT Snu 114位于中心。头部和手臂采用可变的相对位置。这种分子组织和动力学表明催化活化过程中结构事件的可能方案。
The U4/U6-U5 tri-small nuclear ribonucleoprotein (snRNP) is a major, evolutionarily highly conserved spliceosome subunit. Unwinding of its U4/U6 snRNA duplex is a central event of spliceosome activation that requires several components of the U5 portion of the tri-snRNP, including the RNA helicase Brr2, Prp8 and the GTPase Snu114. Here we report the EM projection structure of the Saccharomyces cerevisiae tri-snRNP. It shows a modular organization comprising three extruding domains that contact one another in its central portion. We have visualized genetically tagged tri-snRNP proteins by EM and show here that U4/U6 snRNP forms a domain termed the arm. Conversely, a separate head domain adjacent to the arm harbors Brr2, whereas Prp8 and the GTPase Snu114 are located centrally. The head and arm adopt variable relative positions. This molecular organization and dynamics suggest possible scenarios for structural events during catalytic activation.