Function and regulation of the ETS transcriptional repressor Tel-1/Yan

描述（由申请人提供）：这项工作的长期目标是阐明如何转录！保守信号网络下游的电路调节环境特异性发育反应。因为基因表达的精确调控是所有生物过程的基础，即使是轻微的失衡也会导致严重的缺陷和疾病。我们的方法是利用遗传易处理的果蝇系统来发现基因调控的新策略，在分子机制水平上详细解剖它们，然后确认它们的保守性和与哺乳动物系统的相关性。本提案的目的是研究保守的ETS家族转录抑制因子（果蝇称为Yan，人类称为Tel1）的体内功能和调控。该提案描述了一种多方面的方法，结合体内遗传，分子，生化和基因组分析来解决由Tel1/Yan的SAM结构域介导的同型和异型相互作用允许与染色质的复杂关联，这是发育基因调控所必需的。具体目的是验证Yan自我结合能力是其在体内作为转录抑制因子的功能所必需的假设，研究受调节的Yan聚合允许其扩散到典型高亲和力结合位点侧的染色质的机制，并探索这些调节策略在人类Tel1中的保护作用。这些实验的结果将定义转录抑制的新范式，其中基因特异性转录调控因子的动态聚合可以调节下游靶基因的表达，以响应不断变化的信号条件。

DESCRIPTION (provided by applicant): The long-term objectives of this work are to elucidate how transcriptiona! circuitries operating downstream of conserved signaling networks mediate context-specific developmental responses. Because precisely orchestrated regulation of gene expression is fundamental to all biological processes, even slight imbalances can lead to serious defects and diseases. Our approach is to exploit the genetically tractable Drosophila system to uncover novel strategies of gene regulation, to dissect them in vivo at a molecular mechanistic level of detail, and then to confirm their conservation and relevance to mammalian systems. The goal of this proposal is to investigate the in vivo function and regulation of a conserved ETS family transcriptional repressor, referred to as Yan in Drosophila and Tel1 in humans. The proposal describes a multifaceted approach combining in vivo genetic, molecular, biochemical and genomic assays to address the hypothesis that homo- and heterotypic interactions mediated by the SAM domain of Tel1/Yan permit a complex association with chromatin that is essential for developmental gene regulation. The specific aims are to test the hypothesis that the ability of Yan to self-associate is required for its function as a transcriptional repressor in vivo, to investigate the mechanisms whereby regulated Yan polymerization allows it to spread into chromatin flanking a canonical high affinity binding site, and to explore the conservation of these regulatory strategies with respect to human Tel1. The results of these experiments will define a novel paradigm in transcriptional repression, in which dynamic polymerization of a gene specific transcriptional regulator can modulate expression of downstream target genes in response to changing signaling conditions. Because the signaling molecules we are studying have conserved functions in mammals, and because Tel1 is a frequent target of leukemia-associated chromosomal rearrangements, our findings will be directly applicable to understanding human development and disease. Given that the ability of Tel1 to self-associate is thought to provide a driving force toward malignant transformation in several common leukemias, the mechanistic discoveries emanating from these studies will provide an important foundation for developing novel therapeutic interventions to treat Tell-associated cancers in the future.