The Dynamics of a novel protein complex involved in RNA processing and cell cycle regulation

肾母细胞瘤1相关蛋白（WTAP）是一种广泛表达的核蛋白，参与前体mRNA的剪接。我们已经报道，WTAP参与细胞周期蛋白A2 mRNA的稳定性，从而调节细胞周期，并且WTAP敲除小鼠在早期胚胎阶段表现出增殖失败和死亡。在这项研究中，我们已经开发了一种方法的内源性蛋白质的蛋白质-蛋白质相互作用的功能分析，亲和纯化质谱使用磁珠和高亲和力抗体。利用该方法，我们鉴定了WTAP的几种结合蛋白，包括Vrilizer同源物、E3泛素连接酶、SR蛋白和RNA结合蛋白。此外，我们还发现了WTAP蛋白复合物在细胞周期中的组成变化，表明WTAP蛋白复合物与细胞周期调控有关。

Wilms' tumor 1-associating protein (WTAP) has been reported to be a ubiquitously expressed nuclear protein and supposed to have a role in pre-mRNA splicing. We have reported that WTAP is involved in the stability of cyclin A2 mRNA thereby regulates the cell cycle and WTAP knockout mice exhibited proliferative failure with death at early embryonic stage. In this study, we have developed a method for the functional analysis of protein-protein interactions for the endogenous proteins, by affinity purification mass spectrometry using magnetic beads and high-affinity antibodies. Using the method, we identified several binding proteins of WTAP, including vrilizer homolog, E3 ubiquitin ligase, SR proteins and RNA bindin proteins. Furthermore we found the compositional changes of WTAP protein complex in cell cycle, indicating a relation to cell cle regulation of WTAP protein complex.