GENE REGULATION BY STEROID RECEPTOR PROTEINS

这个项目的长期目标是了解后生动物的转录调控，以及调控因子根据发育或生理线索指定不同的基因表达程序的机制。这项研究的总体策略是分析细胞内受体(IR)超家族成员的调节，该超家族包括类固醇、甲状腺激素、维甲酸和其他小的亲脂配体的受体。组合调控可能反映了多因素调控复合体的受控组装，其组成部分和功能是上下文相关的。因此，IR调节复合体在不同环境中的组装和功能将被机械地剖析，范围从纯蛋白质到整个生物体。本研究的具体目的是表征IR调节复合体在配体(定义细胞特定的背景)或反应元件(定义基因特定的背景)不同的条件下的结构和活性。设想了四个目标：(1)确定配体如何指定不同的功能调节复合体；(2)确定响应元件如何指定基因特异的调节复合体和IR功能；(3)确定与Swi/SNF染色质重塑复合体的受体相互作用的结构和意义；(4)研究简单的后生动物线虫中IR调节复合体的形成和功能。在这些实验中，将使用分子遗传学、生化和结构方法来确定功能表面和相互作用因子，这些表面和相互作用因子指定体外、细胞和整个动物中转录的激活、抑制、复合调控和协同作用。IR与多种疾病有关，包括癌症、高血压和炎症，IR配体被广泛用于治疗、诊断和化学预防。因此，了解IR作用的原理和机制对健康以及发现、治疗和治愈疾病具有重要的意义。

The long term objectives of this project are to understand metazoan transcriptional regulation, and mechanisms by which a regulatory factor can specify different programs of gene expression as a function of developmental or physiological cues. The general strategy of the proposed research is to analyze regulation by members of the intracellular receptor (IR) superfamily, which includes receptors for steroids, thyroid hormone, retinoids, and other small lipophilic ligands. Combinatorial regulation likely reflects the controlled assembly of multifactor regulatory complexes, whose components and functions are context-dependent. Thus, the assembly and functions of IR regulatory complexes in different contexts will be dissected mechanistically, in settings ranging from pure proteins to whole organisms. The specific aims of the present study are to characterize the structure and activities of IR regulatory complexes under conditions in which the ligand (which defines a cell-specific context) or the response element (which defines a gene-specific context) are varied within the complexes. Four goals are envisioned: (1) determine how functionally distinct regulatory complexes are specified by ligands; (2) determine how gene-specific regulatory complexes and IR functions are specified by response elements; (3) determine the structure and significance of receptor interactions with Swi/Snf chromatin remodeling complexes; (4) investigate IR regulatory complex formation and function in the simple metazoan C. elegans. In these experiments, molecular genetic, biochemical and structural approaches will be used to identify functional surfaces and interacting factors that specify transcriptional activation, repression, composite regulation and synergy in vitro, in cells and in whole animals. IRs have been implicated in a wide range of diseases, including cancer, hypertension and inflammation, and IR ligands are widely used as therapeutics, diagnostics and chemopreventatives. Thus, understanding the principles and mechanisms of IR action has important implications for health, and for detecting, treating and curing disease.