The conserved TREX complex has multiple functions in gene expression such as transcription elongation, 3′ end processing, mRNP assembly and nuclear mRNA export as well as the maintenance of genomic stability. In Saccharomyces cerevisiae, TREX is composed of the pentameric THO complex, the DEAD-box RNA helicase Sub2, the nuclear mRNA export adaptor Yra1, and the SR-like proteins Gbp2 and Hrb1. Here, we present the structural analysis of the endogenous TREX complex of S. cerevisiae purified from its native environment. To this end, we used cross-linking mass spectrometry to gain structural information on regions of the complex that are not accessible to classical structural biology techniques. We also used negative-stain electron microscopy to investigate the organization of the cross-linked complex used for XL-MS by comparing our endogenous TREX complex with recently published structural models of recombinant THO–Sub2 complexes. According to our analysis, the endogenous yeast TREX complex preferentially assembles into a dimer.

中文翻译：

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酿酒酵母内源 TREX 复合物的交联质谱分析

保守的TREX复合物在基因表达中具有多种功能，例如转录延伸、3'末端加工、mRNP组装和核mRNA输出以及维持基因组稳定性。在酿酒酵母中，TREX 由五聚体 THO 复合物、DEAD-box RNA 解旋酶 Sub2、核 mRNA 输出接头 Yra1 以及 SR 样蛋白 Gbp2 和 Hrb1 组成。在这里，我们对从天然环境中纯化的酿酒酵母内源 TREX 复合物进行了结构分析。为此，我们使用交联质谱来获得经典结构生物学技术无法获得的复合物区域的结构信息。我们还使用负染色电子显微镜，通过将我们的内源 TREX 复合物与最近发表的重组 THO-Sub2 复合物的结构模型进行比较，研究用于 XL-MS 的交联复合物的组织。根据我们的分析，内源性酵母TREX复合物优先组装成二聚体。