Control of lymphoid effector programs by the E3 ligase cullin 3

描述（由申请人提供）：宿主对病原体感染的防御主要依赖于与特异性先天和适应性淋巴细胞群体相关的效应程序的分化。每个程序都由一个特征转录因子精心编排，但基因调控的机制各不相同，在某些情况下，依赖于相关核蛋白介导的复杂相互作用。BTB- zf转录因子PLZF和Bcl- 6通过其BTB结构域募集一种定义明确的协同抑制因子复合物，从而在由锌指结合的序列特异性靶点诱导染色质修饰。PLZF指导微生物脂质特异性NKT细胞发育获得先天样效应特性，而Bcl-6指导T滤泡辅助细胞（TFH）和生发中心（GC） B细胞的适应性分化。这两个因子也是众所周知的致癌基因，与白血病和淋巴瘤有关。基于广泛的初步研究，我们提出验证PLZF和Bcl6招募一个新的伙伴——E3泛素连接酶cullin 3 （Cul3）的假设，Cul3通过相关核蛋白复合物的泛素化在它们的转录程序中发挥关键作用。本应用程序的目的是表征Cul3与PLZF的关联及其对相应淋巴细胞效应程序的影响。这个项目的基本原理是，它将为宿主防御程序调节的分子细节提供前所未有的见解。反过来，这些见解将允许操纵这些过程以获得治疗益处。提出的假设将通过追求以下具体目标来验证：1)表征在淋巴细胞室缺乏Cul3的小鼠中效应程序的失调；2)表征Cul3的结合和转运；3)对Cul3的靶点进行表征。这些数据将被整合以开发一个

DESCRIPTION (provided by applicant): Host defense against pathogen infection is critically dependent on the differentiation of effector programs associated with specialized populations of innate and adaptive lymphocytes. Each program is orchestrated by a signature transcription factor, but the mechanisms of gene regulation vary and, in some cases, depend on complex interactions mediated by associated nuclear proteins. The BTB-ZF transcription factors PLZF and Bcl- 6 recruit a well-defined co-repressor complex through their BTB domain in order to induce chromatin modifications at sequence-specific target sites bound by their zinc fingers. PLZF directs the developmental acquisition of innate-like effector properties by microbial lipid-specific NKT cells, whereas Bcl-6 directs the adaptive differentiation of the T follicular helper (TFH) and the germinal center (GC) B cells. Both factors are also well-known oncogenes involved in leukemias and lymphomas. Based on extensive preliminary studies, we propose to test the hypothesis that PLZF and Bcl6 recruit a novel partner, the E3 ubiquitin ligase cullin 3 (Cul3), which exerts a critical role on their transcriptional program through ubiquitination of associated nuclear protein complexes. The objective of this application is to characterize the association of Cul3 with PLZF and its impact on the corresponding lymphocyte effector program. The rationale for this project is that it will provide unprecedented insights into the molecular details of regulation of this host defense program. In turn, these insights will allow manipulation of these processes for therapeutic benefit. The proposed hypothesis will be tested by pursuing the following specific aims: 1) to characterize the dysregulation of effector programs in mice lacking Cul3 in their lymphoid compartments; 2) to characterize the binding and transport of Cul3; 3) to characterize the targets of Cul3. The data will be integrated to develop a basic understanding of the role of Cul3 in the transcriptional program directed by PLZF. The proposal is innovative because it explores the function of a novel partner of a family of transcription factors that regulate vital properties of host defense against pathogens. The proposed research is significant because it will enhance our understanding of essential lymphocyte effector programs and generate new concepts and tools that will make it possible to develop agents that target specific regulatory components of immune responses.