Essential Effectors of Myc function

描述(申请人提供)：我们感兴趣的是确定c-myc原癌基因在正常细胞中的功能，以及c-myc蛋白的错误调控或过度表达如何诱导细胞转化。功能研究表明，Myc N-末端的一段片段(称为Myc同源框II或MBII)对于致癌转化是必不可少的。在上一次授予期间，我们能够纯化和鉴定一种名为TRRAP的核辅因子，用于转化/反式激活相关蛋白，它通过MBII与Myc结合。TRRAP的发现已被证明是Myc领域的一项开创性发现，因为它在Myc和乙酰化组蛋白的染色质修饰复合体之间提供了联系。组蛋白乙酰化在生物化学和遗传学上都被证明可以促进基因激活。该项目将解决c-Myc招募TRRAP综合体的职能后果。我们还将探索TRRAP本身更具全球性的功能，以及包含核复合体的TRRAP数量不断增加。具体目标如下：1)我们将对新发现的与Myc和TRRAP相关的蛋白DNA甲基转移酶相关蛋白(DMAP1)的结构和功能进行研究。我们将检验DMAP1是一个关键的Myc相关的组蛋白乙酰转移酶的假设。2)我们将探讨核肌动蛋白相关蛋白BAF53的功能及其在染色质修饰复合体中的作用。具体地说，我们将确定BAF53突变蛋白具有显性抑制活性的生化基础，该突变蛋白在关键功能结构域有少量缺失。3)我们将探索多梳蛋白增强子的功能，它标志着一组独特的HAT复合体。我们将试图确定TRRAP和Epc1之间的复合体与包含TRRAP和DMAP1的复合体有何不同，并将研究这些复合体在基因调控中的作用。4)我们将确定单个HATS和辅助因子在特定细胞靶基因激活中的作用。每种蛋白质在沉默的TERT基因激活中的作用将被讨论。我们将测试Myc和Sp1转录因子在激活沉默的端粒酶逆转录酶(TERT)基因方面的协同作用。

DESCRIPTION (provided by applicant): We are interested in determining the function of the c-myc proto-oncogene in normal cells and how misregulation or overexpression of the c-Myc protein can induce cell transformation. Functional studies have demonstrated that a segment from the N-terminus of Myc (called Myc homology box II or MBII) is essential for oncogenic transformation. In the last granting period, we were able to purify and characterize a nuclear cofactor, called TRRAP, for TRansformation/tRansactivation Associated Protein, that binds to Myc through MBII. The discovery of TRRAP has proven to be a seminal discovery in the Myc field because it provided a link between Myc and chromatin modifying complexes that acetylate histones. Localized histone acetylation has been shown both biochemically and genetically to facilitate gene activation. This project will address the functional consequences of TRRAP complex recruitment by c-Myc. We will also explore the more global function of TRRAP itself and the growing number of TRRAP containing nuclear complexes. The specific aims are as follows: 1) We will characterize the structure and function of DNA Methyltransferase Associated Protein (DMAP1), a newly discovered protein associated with both Myc and TRRAP. We will test the hypothesis that DMAP1 is a critical Myc-associated histone acetyltransferase. 2) We will explore the function of the nuclear actin-related protein BAF53 and its role in chromatin modifying complexes. Specifically, we will determine the biochemical basis for the dominant inhibitory activity of a BAF53 mutant protein with a small deletion in a critical functional domain. 3) We will explore the function of the Enhancer of polycomb protein, which marks a unique set of HAT complexes. We will try to determine how complexes between TRRAP and Epc1 differ from those containing TRRAP and DMAP1, and we will examine the role of these complexes in gene regulation. 4) We will determine the role of individual HATs and cofactors in the activation of specific cellular target genes. The role of each protein in the activation of the silent TERT gene will be addressed. We will test for synergism between Myc and the Sp1 transcription factor in the activation of the silent telomerase reverse transcriptase (TERT) gene.