C-MYC TARGETS IN THE PATHOGENESIS OF HUMAN CANCERS

C-myc癌基因的作用似乎在肿瘤的发生中起着关键作用。 人类癌症的数量。C-Myc蛋白对细胞的积极作用 然而，这种活动背后的分子机制 C-Myc在人类癌症中的作用在很大程度上仍不清楚。虽然意义重大 C-Myc各种功能结构域的研究进展 和Myc伙伴蛋白MAX的发现，已经在 对Myc功能的理解，许多关键问题仍然没有答案。 我们的长期目标是了解c-Myc可能通过哪些机制 有助于人类癌症的发病机制，使潜在的合理 癌症治疗的方法可能会产生。为了达到我们的目标， 我们提出的具体目标是解决以下问题：1)什么是 影响c-Myc激活或抑制能力的蛋白质 抄写？C-Myc的氨基末端结构域是其必需的 功能包括肿瘤转化。使用我们的c-myc突变体和 能够产生大量嵌合c-myc基因的集合 嵌合蛋白，我们发现c-Myc的这个区域包含一个 转录激活区。C-Myc的激活结构域增强 在模型系统中通过不同于 被VP16酸性激活结构域利用的那些。我们提出了策略 识别与转录相互作用并调节转录的蛋白质 C-Myc的激活潜能。2)MAX在肿瘤中的作用是什么 转型？我们已经构建了各种表达载体，能够 以正义或反义的方式表达MAX。实验是 建议划定外源和内源MAX在 Myc和激活的RAS引起的肿瘤细胞转化。3) 在细胞增殖中起关键作用的基因是什么， 是否受Myc监管？我们已经证明了c-Myc基本区域在 DNA结合域可以在功能上替代 酵母中新的遗传系统中的酵母蛋白CBF1。MYC和MAX 将在酵母中表达，以进一步鉴定它们的转录 体内的调节功能。将这种遗传系统与 在体外DNA结合分析中，我们提出了一种识别DNA位点的策略 与Myc-Max介导的肿瘤相关的人类基因组 转型。4)还有没有其他分子可能与 MYC或MAX齐聚结构域？研究蛋白质与蛋白质的相互作用 在活体中，我们开发了一种能够识别cDNA的选择系统 编码与已知靶标齐聚的蛋白质结构域。这个系统 将被用于识别编码其他相互作用的蛋白质的cDNA 和Myc或Max在一起。拟议研究的结果应该提供 对正常的分子机制的重大洞察 C-Myc的功能及其在人类癌症发病机制中的作用在……里面 此外，希望对这些机制的理解将 为潜在的癌症治疗提供合理的分子方法。

The role of the c-myc oncogene appears to be pivotal in the genesis of a number of human cancers. The c-Myc protein contribute positively to cell proliferation; however, the molecular mechanisms underlying the activities of c-Myc in human cancers remain largely unknown. Although significant advances, including identification of various functional domains of c-Myc and the discovery of a Myc partner protein Max, have been achieved in understanding Myc function, numerous critical questions remain unanswered. Our long term objective is to understand the mechanisms by which c-Myc may contribute to the pathogenesis of human cancers so that potential rational approaches to cancer therapy might be generated. To reach our objective, we propose specific aims to address the following questions: 1) What are the proteins that influence the ability of c-Myc to activate or suppress transcription? The amino-terminal domain of c-Myc is necessary for its function including neoplastic transformation. Using our c-myc mutants and an extensive collection of chimeric c-myc genes capable of producing chimeric proteins, we found that this region of c-Myc contains a transcriptional activation domain. The activation domain of c-Myc augments transcription in a model system through factors which are distinct from those utilized by the VP16 acidic activation domain. We propose strategies to identify proteins that interact with and modulate the transcriptional activation potential of c-Myc. 2) What is the role of Max in neoplastic transformation? We have constructed various expression vectors capable of expressing Max in either sense or anti-sense directions. Experiments are proposed to delineate the role of exogenous and endogenous Max in neoplastic cellular transformation caused by Myc and an activated Ras. 3) What are the genes, which play critical roles in cell proliferation, that are regulated by Myc? We have shown that the c-Myc basic region within the DNA binding domain can functionally substitute for the homologous region of the yeast protein CBF1 in a novel genetic system in yeast. Myc and Max will be expressed in yeast to further characterize their transcriptional regulatory function in vivo. Using this genetic system in conjunction with in vitro DNA binding assays, we propose a strategy to identify DNA sites in the human genome that are relevant to Myc-Max mediated neoplastic transformation. 4) Are there other molecules that might interact with the Myc or Max oligomerization domains? To study protein-protein interactions in vivo, we have developed a selection system capable of identifying cDNAs encoding protein domains that oligomerize with a known target. This system will be used to identify cDNAs that encode other proteins which interact with Myc or Max. The findings from the proposed studies should provide significant insights into the molecular mechanisms underlying the normal function of c-Myc and its role in the pathogenesis of human cancers. In addition, it is hoped that the understanding of these mechanisms will provide a rational molecular approach to potential cancer therapeutics.