Essential Effectors of Myc function

描述（由申请人提供）：我们对确定正常细胞中c-myc原癌基因的功能以及c-myc蛋白的错误调节或过表达如何诱导细胞转化感兴趣。功能研究表明，来自Myc n端的一个片段（称为Myc同源盒II或MBII）对致癌转化至关重要。在上一个授权期内，我们能够纯化和表征一个核辅因子，称为TRRAP，用于转化/转激活相关蛋白，通过MBII与Myc结合。TRRAP的发现已被证明是Myc领域的一个开创性发现，因为它提供了Myc和染色质修饰复合物（使组蛋白乙酰化）之间的联系。局部组蛋白乙酰化已被证明在生化和遗传学上促进基因激活。该项目将解决c-Myc招募TRRAP复合体的功能后果。我们还将探讨TRRAP本身的更广泛的功能以及越来越多的含有核配合物的TRRAP。具体目的如下：1)我们将表征DNA甲基转移酶相关蛋白（DNA Methyltransferase Associated Protein, DMAP1）的结构和功能，这是一个新发现的与Myc和TRRAP相关的蛋白。我们将验证DMAP1是一个关键的myc相关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物中的作用。具体来说，我们将确定BAF53突变蛋白在关键功能域有一个小缺失的显性抑制活性的生化基础。3)我们将探索polycomb蛋白增强子的功能，它标志着一组独特的HAT复合物。我们将尝试确定TRRAP和Epc1之间的复合物与含有TRRAP和DMAP1的复合物有何不同，我们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和辅助因子在特定细胞靶基因激活中的作用。每个蛋白质在沉默TERT基因激活中的作用将被解决。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.