Gewartowski Kamil, Cuéllar Jorge, Dziembowski Andrzej, Valpuesta José María
Institute of Biochemistry and Biophysics; Polish Academy of Sciences; Warsaw, Poland; Department of Genetics and Biotechnology; Faculty of Biology; University of Warsaw; Warsaw, Poland.
Department of Structure of Macromolecules; Centro Nacional de Biotecnología (CNB-CSIC); Madrid, Spain.
Bioarchitecture. 2012 Jul-Aug;2(4):134-7. doi: 10.4161/bioa.21181. Epub 2012 Jul 1.
The THO complex is a nuclear structure whose architecture is conserved among all kingdoms and plays an important role in mRNP biogenesis connecting transcription elongation with mRNA maturation and export. Recent data indicates that the THO complex is necessary for the proper expression of some genes, assurance of genetic stability by preventing transcription-associated recombination. Yeast THO has been described as a heterotetramer (Tho2, Hpr1, Mft1 and Thp2) that performs several functions through the interaction with other proteins like Tex1 or the mRNA export factors Sub2 and Yra1, with which it forms the TRanscription and EXport complex (TREX). In this article we review the cellular role of THO, which we show to be composed of five subunits with Tex1 being also an integral part of the complex. We also show a low-resolution structure of THO and localize some of its components. We discuss the consequences of THO interaction with nucleic acids through the unfolded C-terminal region of Tho2, highlighting the importance of unfolded regions in eukaryotic proteins. Finally, we comment on THO recruitment to active chromatin, a role that is linked to mRNA biogenesis.
THO复合体是一种核结构，其结构在所有生物界中都保守，并且在将转录延伸与mRNA成熟和输出相联系的mRNP生物合成中发挥重要作用。最近的数据表明，THO复合体对于某些基因的正确表达是必需的，通过防止转录相关的重组来确保遗传稳定性。酵母THO被描述为一种异源四聚体（Tho2、Hpr1、Mft1和Thp2），它通过与其他蛋白质（如Tex1或mRNA输出因子Sub2和Yra1）相互作用来执行多种功能，与之形成转录与输出复合体（TREX）。在本文中，我们综述了THO的细胞作用，我们发现它由五个亚基组成，其中Tex1也是该复合体的一个组成部分。我们还展示了THO的低分辨率结构并定位了其一些组分。我们讨论了通过Tho2未折叠的C末端区域THO与核酸相互作用的后果，强调了真核生物蛋白质中未折叠区域的重要性。最后，我们评论了THO被招募到活性染色质上的情况，这一作用与mRNA生物合成相关。
