Essential Effectors of Myc function

描述（由申请人提供）：我们感兴趣的是确定正常细胞中c-myc原癌基因的功能，以及c-Myc蛋白的失调或过表达如何诱导细胞转化。功能研究已经证明，来自Myc的N-末端的片段（称为Myc同源盒II或MBII）对于致癌转化是必需的。在最后一个授权期间，我们能够纯化和表征一种称为TRRAP的核辅因子，即通过MBII与Myc结合的转录/转录激活相关蛋白。TRRAP的发现已被证明是Myc领域的开创性发现，因为它提供了Myc与乙酰化组蛋白的染色质修饰复合物之间的联系。局部组蛋白乙酰化已被证明在生物化学和遗传学上促进基因激活。该项目将解决TRRAP复合物招募c-Myc的功能后果。我们还将探讨TRRAP本身的更全球性的功能和越来越多的TRRAP含有核复合物。具体目的如下：1）对新发现的与Myc和TRRAP相关的DNA甲基转移酶相关蛋白（DMAP 1）的结构和功能进行了研究。我们将测试的假设，DMAP 1是一个关键的Myc相关的组蛋白乙酰转移酶。2)我们将探讨核肌动蛋白相关蛋白BAF 53的功能及其在染色质修饰复合物中的作用。具体来说，我们将确定一个BAF 53突变蛋白的主要抑制活性的生化基础，在一个关键的功能域中有一个小的缺失。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复合物。我们将试图确定TRRAP和Epc 1之间的复合物与包含TRRAP和DMAP 1的复合物有何不同，并将研究这些复合物在基因调控中的作用。4)我们将确定单个HAT和辅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基因的激活中的作用将得到解决。我们将测试Myc和Sp1转录因子在沉默端粒酶逆转录酶（TERT）基因激活中的协同作用。

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.