Functional Analysis of Nuclear Receptors

核受体超家族的成员是进化相关的dna结合转录因子。目前的研究计划的重点是组成型雄激素受体（CAR；基因名称NR1I3），它调节特定基因的表达，不仅涉及葡萄糖稳态、脂质代谢和骨稳态，还涉及外源物质（也称为外来化学物质，如药物、草药和环境污染物）和内源性物质（如激素、维生素和脂肪酸）的运输、生物激活和解毒。我的研究计划的长期目标是加强我们对各种分子和细胞因子的理解，这些因子调节核受体（例如CAR）的功能和表达，这些核受体参与控制基因的表达，这些基因在外源物质和内源性物质的运输、生物激活和解毒中发挥重要作用。具体的短期目标是：1)鉴定调节人类CAR野生型亚型（hCAR-WT）表达和功能的microrna；2)描述特定hCAR剪接变异体（如hCAR- sv22和hCAR- sv26）的功能，并确定hCAR同工型的功能是否受到其他核受体的调节。在Aim #1下，需要解决的实验问题将包括：1)microRNA对hCAR-WT表达和功能的影响及其对hCAR-WT靶基因表达的影响；2)微rna调控视黄酸X受体α (rxr - α)对hCAR转录活性的影响；3) hCAR-WT配体对microrna表达的影响，包括调控hCAR-WT表达和功能的microrna。在目标#2下，实验问题是：1)表征特定hCAR剪接变体的功能（例如hCAR- sv22和hCAR- sv26）；2)确定各种hCAR亚型（如hCAR- wt、hCAR- sv23、hCAR- sv24）与其他核受体（如小异源二聚体伴侣（SHP）和肝X受体α (lxr - α)）之间是否存在功能相互作用（即串扰）。我们提出的研究计划将增强我们对表观遗传学对hCAR的表达和功能的影响，人类CAR的各种剪接变体的功能，以及它们是否受到其他核受体的调节的基本理解。所产生的信息将帮助我们预测和解释我们对内源性物质和包括药物在内的外源性物质如何反应的个体间差异，并增加我们对调节hCAR表达和功能的各种因素的理解。

Members of the superfamily of nuclear receptors are evolutionarily-related DNA-binding transcription factors. The focus of the current research proposal is on the constitutive androstane receptor (CAR; gene designation NR1I3), which regulates the expression of specific genes involved not only in glucose homeostasis, lipid metabolism, and bone homeostasis, but also transport, bioactivation, and detoxification of xenobiotics (also referred to as foreign chemicals; e.g. drugs, herbal medicines, and environmental pollutants) and endogenous substances (e.g. hormones, vitamins, and fatty acids). The longer-term objective of my research program is to enhance our understanding of the various molecular and cellular factors that regulate the function and expression of nuclear receptors (e.g. CAR) involved in controlling the expression of genes that play an important role in the transport, bioactivation, and detoxification of xenobiotics and endogenous substances. The specific short-term aims are to: 1) identify microRNAs in regulating the expression and function of the wild-type isoform of human CAR (hCAR-WT); and 2) delineate the function of specific hCAR splice variants (e.g. hCAR-SV22 and hCAR-SV26) and determine whether the function of hCAR isoforms is subject to regulation by other nuclear receptors. Under Aim #1, the experimental issues to be addressed will include: 1) the effect of microRNA on expression and function of hCAR-WT and the consequence on hCAR-WT target gene expression; 2) the consequences of microRNA regulation of retinoic X receptor-alpha (RXR-alpha) on hCAR transcriptional activity; and 3) the effect of ligands of hCAR-WT on expression of microRNAs, including the ones that regulate the expression and function of hCAR-WT. Under Aim #2, the experimental issues are to: 1) to characterize the functionality of specific hCAR splice variants (e.g. hCAR-SV22 and hCAR-SV26); and 2) determine whether there is functional interaction (i.e. cross-talk) between the various hCAR isoforms (e.g. hCAR-WT, hCAR-SV23, hCAR-SV24) and other nuclear receptors, such as small heterodimer partner (SHP) and liver X receptor-alpha (LXR-alpha). Our proposed research program will enhance our fundamental understanding of the influence of epigenetics on the expression and function of hCAR, the functionality of the various splice variants of human CAR, and whether they are subject to regulation by other nuclear receptors. The information generated will help us to predict and explain inter-individual differences in how we respond to endogenous substances and xenobiotics, including drugs, and increase our understanding of the various factors that regulate hCAR expression and function.