AP-1 Complexes and Target Gene Regulation

描述（由申请人提供）：细胞内信号在转录因子如激活蛋白-1 （AP-1）介导的基因表达变化中达到顶峰。AP-1是一种广泛表达的转录复合体，由二聚碱性亮氨酸拉链（bZIP）蛋白组成。AP-1在细胞生长、分化、存活和凋亡中起作用，而AP-1活性失调在从癌症到神经退行性疾病的人类疾病中占有重要地位。转录因子是治疗干预的主要靶点，而设计用于调节AP-1活性的体内策略将在许多临床情况下取得重大进展。BATF和高度相关的JDP1蛋白是AP-1家族中独特的成员，它们与AP-1的核心成分（Jun蛋白）二聚并抑制AP-1的活性。本应用程序的目的是确定这些AP-1抑制剂在体内的作用，并验证这些作用与特定AP-1靶基因的调节有关的假设。在Aim 1中，内源性水平表达表位标记的BATF和JDP1的基因工程小鼠模型将用于定义这些蛋白质的精确表达模式，并使用染色质免疫沉淀（ChIP）结合新型AP-1启动子微阵列筛选鉴定BATF直接结合的基因。BATF缺失、JDP1缺失和双缺失小鼠将被用来评估由这些蛋白介导的AP-1抑制丧失如何影响发育，并描绘BATF缺失表型特征的基因表达变化的全谱。目的2将使用质谱分析来识别和量化离散磷酸化事件，这些磷酸化事件调节BATF的DNA结合和二聚化特性，并影响其作为AP-1抑制剂的功效。最后，在Aim 3中，M1细胞系统将通过跟踪BATF介导的靶基因调控，并将BATF定位在控制这些细胞分化的信号网络中，进一步研究BATF的功能。这些研究的短期目标是确定BATF和JDP1在体内的功能，并将产生必要的信息，以解决我们使用这些AP-1抑制剂进行转录靶向治疗的长期目标。

DESCRIPTION (provided by applicant): Intracellular signaling culminates in gene expression changes that are mediated by transcription factors such as activator protein-1 (AP-1). AP-1 is a widely expressed transcription complex consisting of dimerizing basic leucine zipper (bZIP) proteins. AP-1 functions in cell growth, differentiation, survival and apoptosis, and deregulated AP-1 activity figures prominently in human diseases from cancer to neurodegenerative disorders. Transcription factors are major targets for therapeutic intervention, and in vivo strategies designed to modulate AP-1 activity would be a significant advance in many clinical situations. BATF, and the highly related JDP1 protein, are unique AP-1 family members that dimerize with the central components of AP-1 - the Jun proteins - and inhibit AP-1 activity. The objective of this application is to define the roles of these AP-1 inhibitors in vivo and to test the hypothesis that these roles are linked to the regulation of specific AP-1 target genes. In Aim 1, genetically engineered mouse models expressing epitope-tagged BATF and JDP1 at endogenous levels will be used for defining the precise expression patterns of these proteins and for identifying genes directly bound by BATF using chromatin immunoprecipitation (ChIP) coupled with the screening of novel AP-1 promoter microarrays. BATF null, JDP1 null and double null mice will be used to assess how the loss of AP-1 inhibition mediated by these proteins affects development and to profile the full spectrum of gene expresson changes that characterize the BATF null phenotype. Aim 2 will use mass spectral analysis to identify and quantify discreet phosphorylation events that regulate the DNA binding and dimerization properties of BATF and influence its efficacy as an AP-1 inhibitor. Lastly, in Aim 3, the M1 cell system will be used to further investigate the function of BATF by following BATF-mediated regulation of target genes and by positioning BATF within the signaling network that controls the differentiation of these cells. These studies have the short-term goal of establishing the function of BATF and JDP1 in vivo and will generate the information necessary to address our long-term goals of using these AP-1 inhibitors for transcription-targeted therapies. Relevance: The aberrant cell growth that is a feature of many human diseases often is linked to deregulated gene expression mediated by proteins such as the AP-1 family of transcription factors. BATF and JDP1 have been identified as AP-1 family members that negatively regulate gene expression. The goal of this research is to fully characterize the biological activities of these proteins as a first step towards establishing their utility in AP-1 targeted therapies.