Regulation of pre-mRNA splicing fidelity by the Nineteen Complex (NTC)

细胞内的基因被复制成前信使RNA (pre-mRNA)，用作蛋白质生产的模板。基因中包含的所有信息并不是制造蛋白质所必需的。因此，在pre-mRNA用于蛋白质生产之前，必须将不需要的信息从mrna中去除。不需要的信息通过类似于从电影中编辑不需要的帧的过程从pre-mRNA中删除或“拼接”。要去除的区域的一端首先被切割，然后另一端被切割，而剩下的两个部分被“拼接”在一起。前mrna的这种“剪接”非常重要，因为它必须准确地发生，才能产生功能性蛋白质。剪接的调控在人类生物学的各个方面都是必不可少的。剪接是胚胎正常发育和所有组织器官分化所必需的。前mrna剪接的调节对于生物体对环境的反应和适应压力和营养剥夺也至关重要。前mrna剪接缺陷与多种疾病相关，包括糖尿病、癌症和年龄相关疾病。选择性剪接还允许人类在不增加基因组大小的情况下扩大细胞的复杂性。这里将进行的工作将解决剪接过程是如何发生的，因为关于pre-mRNA剪接是如何调节的还有一些关键的未解问题。剪接是由一个叫做剪接体的大型RNA/蛋白质复合物进行的。剪接体必须将自身排列成特定的构象，以识别和“剪接”出不需要的区域。越来越多的证据表明，一种叫做19复合物（NTC）的蛋白质复合物与剪接体相结合，作为剪接体功能的基本调节器。在提出这一建议的工作中，我们已经确定了一种名为Cwc2的NTC蛋白，它提供了NTC蛋白与剪接体活性位点之间的直接联系。发现NTC和剪接体之间的这种联系对科学家现在如何理解前mrna剪接调节机制具有重要意义。由于我们是第一个发现这种联系的研究人员，我们现在在发现这种联系如何促进前mrna剪接的调节方面具有优势。在这项研究资助期间提出的工作将通过一系列详细的分子实验来解决Cwc2如何参与调节剪接两步所需的剪接体构象。由于pre-mRNA剪接的基本机制在酵母细胞和人类细胞中是相同的，我们避免在我们的研究中使用动物，而是使用酵母细胞进行我们的实验。

Genes within cells are copied into a pre-messenger RNA (pre-mRNA) which is used as a template for protein production. All the information contained within genes is not required for making proteins. The unwanted information, therefore, must be removed from the pre-mRNA before it is used for protein production. The unwanted information is removed, or 'spliced', from pre-mRNA by a process similar to the editing of unwanted frames from a film. One end of the region to be removed is first cut then the other end is cut while the two remaining pieces are 'spliced' together. This 'splicing' of the pre-mRNA is very important because it must occur accurately in order for functional proteins to be produced. The regulation of splicing is essential for all aspects of human biology. Splicing is required for proper embryo development and differentiation of all tissues and organs. Regulation of pre-mRNA splicing is also vital for organisms to respond to their environment and adapt to stresses and nutrient deprivation. Defects in pre-mRNA splicing are associated with a wide range of diseases including diabetes, cancer and age related diseases. Alternative splicing has also allowed humans to expand their cellular complexity without having to increase the size of their genome. The work that will be undertaken here will address how the process of splicing occurs as there are still some key unanswered questions on how pre-mRNA splicing is regulated. Splicing is carried out by a large RNA/protein complex called the spliceosome. The spliceosome must arrange itself into specific conformations to identify and 'splice' out the unwanted regions. An increasing amount of evidence points to a complex of proteins called the NineTeen Complex, or NTC, that associates with the spliceosome to act as an essential regulator of spliceosome function. In work leading up to this proposal we have identified an NTC protein called Cwc2 that provides the direct link between proteins of the NTC and the active site of the spliceosome. Discovering this link between the NTC and the spliceosome has implications for how scientists now understand the mechanisms of pre-mRNA splicing regulation. As we are the first researchers to discover this link we now have an advantage in discovering exactly how this link contributes to the regulation of pre-mRNA splicing. Work proposed during the tenure of this research grant will address how Cwc2 is involved in regulating spliceosome conformations required for the two steps of splicing through a set of detailed molecular experiments. As the basic mechanisms of pre-mRNA splicing are identical in yeast and human cells, we avoid using animals in our research by using yeast cells to perform our experiments .