Regulation of Gene Expression by the Yeast Cap Binding Complex: Coordinating Transcription and RNA Processing

智力上的功绩。基因信息的正确表达对细胞执行的每一项功能都至关重要。基因表达的第一步是从DNA模板合成信使RNA分子。这种信使RNA(MRNA)必须经过广泛的加工，才能将这种分子从细胞核中排出，并翻译成维持细胞功能的蛋白质。作为其“加工”的一部分，RNA必须在其两端进行修饰，以确保其稳定性和出口。此外，中断RNA蛋白质编码序列的非编码序列必须通过mRNA剪接过程去除。基因表达的每一步--从信使RNA的合成到其广泛的加工--都是一个潜在的调控目标。虽然这些调控步骤中的每一个在历史上都被作为一种不同的生化反应来研究，但近年来已经变得明显的是，这些过程是高度相互关联和协调的，这种协调是基因调控的一个基本特征。然而，识别和表征协调这些反应的因素的功能仍然是一个艰巨的挑战。这里描述的研究强调了酵母帽结合复合体(CBC)在严格控制RNA合成中的意外作用。CBC是一种蛋白质复合体，与mRNA的5‘端结合，在RNA剪接和RNA加工中具有很好的特征。这项工作探索了由帽结合复合体协调的广泛的相互作用网络，并阐明了CBC调节RNA合成并协调RNA合成与基因表达的其他各个步骤的机制。与该项目相关的教育活动侧重于采取有针对性的方法，为传统上在科学界代表性较低的群体的学生提供更多机会。利用从以前的教育和外展努力中获得的广泛技能和经验，这一教育计划有两个主要目标。首先，将制定战略，与少数族裔学生人数较多的当地高中持续接触。这些具体的外展活动使学生获得指导研究的机会，并帮助教师制定将高中课程与尖端基因表达研究相结合的课程。此外，他们还建立机制，促进这些学生过渡到本科学习，并最终进入生物科学领域。第二个目标是为加州大学圣地亚哥分校的少数族裔本科生开发研究机会，扩大这些代表性不足的群体在科学领域的参与。

Intellectual Merit. Proper expression of genetic information is crucial to every function performed by the cell. One of the first steps in gene expression is the synthesis of a messenger RNA molecule from its DNA template. This messenger RNA (mRNA) must be extensively processed in order for this molecule to be exported from the cell nucleus and translated to make the proteins that sustain the functions of the cell. As part of its "processing" the RNA must be modified at both of its ends to ensure its stability and export. Furthermore, noncoding sequences that interrupt the protein-coding sequence of the RNA must be removed through the process of mRNA splicing. Each step in gene expression--from the synthesis of messenger RNAs to their extensive processing--is a potential target of regulation. Although each of these regulatory steps has been historically studied as a biochemically distinct reaction, in recent years it has become clear that these processes are highly interconnected and coordinated, and that this coordination is an essential feature of gene regulation. However, identifying and characterizing the functions of the factors that coordinate these reactions has remained a difficult challenge. The research described here highlights the unexpected role for the yeast cap binding complex (CBC), a protein complex that binds to the 5' end of the mRNA and has well-characterized roles in RNA splicing and RNA processing, in tight control of RNA synthesis. This work explores the extensive network of interactions that are orchestrated by the cap binding complex and elucidates the mechanisms by which the CBC acts to regulate RNA synthesis and coordinate RNA synthesis with the various other steps of gene expression.Broader Impacts. Educational activities associated with this project focus on directed approaches to increase access and opportunities for students from groups traditionally underrepresented in the sciences. Using skills and experiences acquired from a broad repertoire of previous education and outreach endeavors, this educational plan has two main goals. First, strategies will be developed for sustained engagement with local high schools with high populations of underrepresented minority students. These specific outreach activities expose students to mentored research opportunities and assist teachers in developing curricula that integrate the high school curriculum with cutting-edge gene expression research. Furthermore, they establish mechanisms to facilitate these students' transitions to undergraduate studies and, ultimately, to careers in the biological sciences. The second goal is to develop research opportunities for minority undergraduates at University of California-San Diego that will broaden participation of these underrepresented groups in the sciences.