Role of Set1-mediated methylation in chromatin functioin

描述（申请人提供）：染色质的动态调控是基因调控的重要机制。许多研究表明，组蛋白的翻译后修饰如乙酰化、磷酸化、泛素化和/或甲基化是调节染色质环境和基因表达谱的一种机制。当这些组蛋白修饰活动被破坏（即突变、扩增和染色体易位）时，许多与人类癌症有关。因此，研究介导这些修饰的机制将使我们更好地了解真核基因组是如何被调节的，以及这些修饰活动的错误调节是如何导致人类疾病的。本研究的长期目标是了解出芽酵母组蛋白H3 Lys4甲基转移酶Set1及其相关蛋白在基因调控中的生物学作用。为了实现这一目标，我们将结合分子、生化和遗传方法来确定Set1相关蛋白在组蛋白甲基化中的重要性，鉴定新的Set1相关蛋白，并表征Set1调节甲基转移酶活性的功能域。了解Set1和Set1相关蛋白的基本功能以及它们如何介导H3 Lys4甲基化，将有助于进一步了解Set1如何介导基因调控，如转录激活、延伸和/或沉默。最后，我们预测我们的研究结果将具有广泛的意义，因为许多含有SET结构域的蛋白质存在于其他生物中，如植物、昆虫和动物。此外，存在几种Set1 H3 Lys4甲基转移酶的人类同源物（例如，MLL1、MLL2和Set9），并与癌症有关。因此，了解Set1在酵母中的功能可能为理解含有SET结构域的甲基转移酶如何导致人类疾病（如癌症）提供关键见解。

DESCRIPTION (provided by applicant): The dynamic regulation of chromatin serves as an important mechanism for gene regulation. Many studies have demonstrated that posttranslational modification such as acetylation, phosphorylation, ubiquitination, and/or methylation of histones is a mechanism that regulates the chromatin environment and gene expression profiles. Many of these histone modifying activities, when disrupted (i.e., mutations, amplifications and chromosomal translocations), are associated with human cancers. Therefore, studying the machinery that mediates these modifications will provide us with a better understanding of how eukaryotic genomes are regulated and how mis-regulation of these modifying activities can lead to human diseases. The long-term objective of this proposal is to understand the biological role of Set1, the budding yeast histone H3 Lys4 methyltransferase, and its associated proteins in gene regulation. To achieve this goal we will use a combination of molecular, biochemical and genetic approaches to determine the importance of Set1-associated proteins in histone methylation, identify novel Set1-associated proteins, and characterize the functional domains of Set1 that regulate methyltransferase activity. Understanding the basic function of Set1 and Set1-associated proteins and how they mediate H3 Lys4 methylation will provide further mechanistic insight into how Set1 mediates gene regulation such as transcriptional activation, elongation and/or silencing. Finally, we predict that results from our studies will have wide implications since many SET domain-containing proteins exist in other organisms such as plants, insects and animals. Furthermore, several Set1 H3 Lys4 methyltransferase human homologues exist (e.g., MLL1, MLL2, and Set9) and have been associated with cancers. Therefore, understanding how Set1 functions in yeast may provide key insights into understanding how SET domain-containing methyltransferases lead to human diseases such as cancer.