Activator-Targeted Subunits of the ARC/Mediator

描述(由申请人提供)： 胆固醇和脂肪酸稳态的异常与许多常见疾病有关，如动脉粥样硬化、阿尔茨海默病和癌症。SREBPs是控制胆固醇和脂肪酸稳态的关键基因，因此阐明SREBPs转录调控的分子机制有助于寻找可能具有临床实用价值的新的胆固醇和脂肪酸生物合成的化学调节剂。我们将剖析ARC/Mediator共激活因子在SREBP基因调控中的作用。其具体目的是：1.确定ARC/Mediator和ARC105亚基在SREBP家族转录因子激活基因中的功能作用。我们将使用我们基于染色质的体外转录系统和RNAi，然后进行DNA微阵列分析，确定ARC/Mediator和ARC 105在SREBP激活剂家族转录调控中的功能参与。这些研究将阐明ARC/Mediator在SREBP基因激活程序中的作用，并加深我们对ARC105亚单位作为关键激活靶的理解。Ii.确定不同共激活子中的KIX结构域是否作为SREBPs的重要功能相互作用模块。我们将研究SREBPs如何与假定的ARC105 KIX结构域在分子和功能上相互作用，并与CBP和p300 KIX结构域进行比较。这些研究将确定不同类型的共激活剂中的KIX结构域是否可以作为SREBPs的对接模块，并将为某些激活剂如何结合多个共激活剂提供见解。鉴定SREBP靶基因的激活子和共激活子之间的分子和功能相互作用。我们将使用RNAi和染色质免疫沉淀(CHIP)相结合的方法来确定SREBPs与ARC/Mediator和CBP/p300共激活因子在体内不同SREBP靶基因上的动态相互作用。这些研究将进一步加深我们对激活子和含有KIX结构域的共激活子的个体、合作或竞争作用的理解，以及它们在体内SREBP依赖的基因激活中的招募动态。

DESCRIPTION (provided by applicant): Abnormalities in cholesterol and fatty acid homeostasis have been implicated in a number of common diseases, such as atherosclerosis, Alzheimer's disease, and cancers. SREBPs are critical regulators of genes controlling cholesterol and fatty acid homeostasis, hence elucidation of the molecular mechanism of transcription regulation by SREBPs could assist efforts to identify novel chemical modifiers of cholesterol and fatty acid biosynthesis that may have clinical utility. We will dissect the role of the ARC/Mediator coactivator in SREBP gene regulation. The Specific Aims are: I. To determine the functional role of ARC/Mediator and the ARC105 subunit in gene activation by the SREBP family of transcription factors. We will determine the functional involvement of the ARC/Mediator and ARC 105 in transcription control by the SREBP family of activators using our chromatin based in vitro transcription system and RNAi followed by DNA microarray analysis. These studies will clarify the role of the ARC/Mediator in SREBP gene activation programs, and increase our understanding of the ARC105 subunit as a critical activator-target. II. To determine whether KIX domains in distinct co-activators serve as functionally important interaction modules for SREBPs. We will examine how SREBPs interact molecularly and functionally with the putative ARC105 KIX domain in comparison with the CBP and p300 KIX domains. These studies will determine whether KIX domains in different types of co-activators may serve as docking modules for SREBPs and will provide insights into how certain activators can bind multiple co-activators. III. To identify the molecular and functional interplay of activators and co-activators at SREBP target genes. We will use a combination of RNAi and chromatin immunoprecipitation (ChIP) to determine the dynamic interplay of SREBPs and the ARC/Mediator and CBP/p300 co-activators on different SREBP target genes in vivo. The proposed investigations will further our understanding of the individual, cooperative, or competitive roles of activators and KIX domain-containing co-activators and their recruitment dynamics in SREBP-dependent gene activation in vivo.