Coupling of transcription elongation and termination with pre-mRNA processing

项目摘要/摘要 信使rna(Mrna)的产生是基因表达的主要事件，其中 信息从基因的DNA转移到一次性的RNA拷贝中。这件事的腐败 这一过程是包括癌症在内的许多疾病的标志。信使核糖核酸合成不仅需要 RNA转录本的合成，但转录本的成熟是通过5‘端封端、内含子的切除 外显子的剪接和3‘末端的形成，通过切割和Polya尾部加成。信使核糖核酸 从根本上改变初级转录本的处理步骤在很大程度上是共转录的； 这就是说，mRNA加工的底物是生长的新生RNA，它被 一种RNA聚合酶II(PolII)分子，其速率为500-5000碱基/分钟。我们的工作模式是 信使核糖核酸前体的合成和加工是在 包含RNA聚合酶和加工因子的动态“信使核糖核酸工厂”复合体 其中一些与POLII C-末端结构域(CTD)直接接触。我们的工作目标是 是为了了解RNA链的转录增长是如何与其折叠成 RNA二级结构，它与RNA结合蛋白的结合，以及它的成熟 剪接和3‘端形成。新生RNA新陈代谢的这些重要特征都是 受核糖核酸链增长速度的影响。因此，很重要的一点是要发现， POL II在沿着基因行进时受到控制。当POL II完成它的旅程，直到 基因，高度稳定的转录延伸复合体必须被主动分解才能循环使用 这种酶可以防止它侵入邻近的基因。我们将调查这一过程是如何 转录终止是在基因的3‘端以精心控制的方式实现的，并且 在基因内也有可能发生“过早”终止的情况。我们将使用基因和基因组 人类细胞研究这三个关键挑战的方法： 一、前mRNA加工、新生RNA折叠、RNA 结合蛋白(RBP)结合和转录延伸？ 转录延伸的速度是如何调节的？ 三、是什么机制终止了PolII基因及其下游的转录 基因?

Project Summary/Abstract The production of messenger RNA (mRNA) is the primary event in gene expression where genetic information is transfered from the gene’s DNA into a disposable RNA copy. Corruption of this process is a hallmark of many diseases including cancer. mRNA synthesis requires not only synthesis of an RNA transcript but maturation of that transcript by 5’ capping, excision of introns and splicing of exons and 3’ end formation by cleavage and polyA tail addition. The mRNA processing steps that radically transform the primary transcript occur largely co-transcriptionally; that is to say the substrate of mRNA processing is the growing nascent RNA that is extruded by an RNA polymerase II (pol II) molecule at rates of 500-5000 bases/min. Our working model is that synthesis and processing of a mRNA precursor are carried out in an integrated fashion within a dynamic 'mRNA factory' complex that includes both RNA polymerase and processing factors some of which make direct contacts with the pol II C-terminal domain (CTD). The goal of our work is to understand how growth of the RNA chain by transcription is coordinated with its folding into RNA secondary structures, its association with RNA binding proteins, and its maturation by splicing and 3’ end formation. These important features of nascent RNA metabolism are all affected by how fast the RNA chain grows. Therefore it is important to discover how the speed of pol II is controlled as it travels along genes. When pol II completes its journey to the end of the gene, the highly stable transcription elongation complex must be actively disassembled to recycle the enzyme and prevent it from invading neighboring genes. We will investigate how the process of transcription termination is achieved in carefully controlled ways at the 3’ ends of genes and also within genes where termination can occur “prematurely”. We will use genetic and genomic approaches in human cells to investigate these three Key Challenges: I. What is the relation between pre-mRNA processing, nascent RNA folding, RNA binding protein (RBP) binding, and transcription elongation? II. How is the speed of transcription elongation regulated? III. What mechanisms terminate pol II transcription within genes and downstream of genes?