A Novel Paradigm for Aryl Hydrocarbon Receptor Signaling

芳基烃受体信号传导的新范例

基本信息

批准号：
8896257
负责人：
Cornelis Johan Elferink
金额：
$ 23.25万
依托单位：
UNIVERSITY OF TEXAS MED BR GALVESTON
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-05-01 至 2017-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8896257
关键词：
ARNT protein Abbreviations Amino Acids Aryl Hydrocarbon Receptor Binding Biological Biological Assay Biology Bromodeoxyuridine CDK2 gene Cell Cycle Arrest Cell Cycle Progression ChIP-seq Co-Immunoprecipitations Complex Coupled Cyclin-Dependent Kinases DNA DNA Binding DNA Binding Domain DNA-Protein Interaction Data Dimethyl Sulfoxide Dioxins EMSA Environmental Pollutants Environmental Pollution Evaluation Event Exposure to Functional disorder Future G1 Phase Gene Expression Gene Expression Profile Gene Targeting General Population Genetic Transcription Genomics Green Fluorescent Proteins Health Helix-Turn-Helix Motifs Hepatic Heterodimerization Human Immune System Diseases Injury Knock-out Ligands Liver Regeneration Malignant Neoplasms Mediating Mediator of activation protein Molecular Outcome Partial Hepatectomy Pathway interactions Plasminogen Activator Inhibitor 1 Process Proteins Receptor Signaling Recombinant Proteins Recruitment Activity Research Research Design Response Elements Risk Shotgun Sequencing Signal Transduction Site Tertiary Protein Structure Testing Tetrachlorodibenzodioxin Time Toxic effect Transactivation Tumor Suppressor Proteins Work Xenobiotics activating transcription factor chromatin immunoprecipitation deep sequencing design fetal bovine serum human ARNT protein inhibitor/antagonist innovation mutant novel pollutant prevent public health relevance receptor receptor binding receptor function retinoblastoma tumor suppressor transcriptome sequencing

项目摘要

DESCRIPTION (provided by applicant): The Aryl hydrocarbon Receptor (AhR) is a mediator of xenobiotic toxicity, best recognized for conveying the deleterious human health effects following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related environmental contaminants. Mechanistically, the AhR is known to function as a ligand-activated transcription factor that binds to a canonical xenobiotic response element (XRE) in association with its heterodimerization partner, the AhR nuclear translocator (Arnt) protein. However, within the repertoire of AhR target genes identified in recent years, many lack a clearly defined XRE, highlighting the growing realization that AhR-mediated gene expression appears to involve additional mechanisms distinct from the well-characterized process involving the XRE. We recently identified a non-consensus XRE (NC-XRE) that recruits the AhR in conjunction with a novel DNA binding partner, the Krüppel-like factor 6 (KLF6) tumor suppressor. DNA binding and functional studies confirmed that NC-XRE binding by the AhR-KLF6 complex is independent of the Arnt protein. The toxicological ramification of TCDD-induced AhR-KLF6 activity is revealed in liver regeneration studies. Our previous work established that TCDD inhibits normal liver regeneration following injury, by suppressing G1 phase cyclin-dependent kinase (CDK) activity, specifically CDK2. Increased CDK2 activity is necessary for G1 phase cell cycle progression, and inhibition of CDK2 activity leads to cell cycle arrest. New data demonstrate that the TCDD-induced inhibition of liver regeneration is directly tied to AhR-dependent expression of the CDK2 inhibitor, p21Cip1. The results confirm that p21Cip1 is an AhR target gene, and that its induction relies on NC-XRE-mediated AhR-KLF6 activity. A preliminary analysis of the AhR-KLF6 protein-DNA interaction revealed that deletion of the AhR's DNA binding domain required for XRE binding did not prevent receptor binding to the NC-XRE. Hence, we hypothesize that AhR-NC-XRE binding and function is fundamentally different from signaling through the XRE. In keeping with our long-term objective to understand the pathophysiology of AhR activity, this proposal will examine two specific aims designed to characterize this novel NC-XRE regulatory complex as a platform for future studies designed to explore AhR-KLF6 signaling. Specific aim 1 describes a detailed characterization and functional analysis of the NC-XRE protein-DNA complex. Specific Aim 2 will use ChIP-seq and RNA-seq to provide a global genomic assessment of the functional NC-XRE sites regulated by the AhR/KLF6 transcriptional complex. Identification of this novel AhR complex represents a paradigm shift in our understanding of AhR biology and TCDD toxicity.

描述（由申请人提供）：芳基烃受体（AHR）是异生物生物毒物的介体，以在暴露于2,3,7,8-tetrachlorodibenzo-p-dioxin（TCDD，dioxin）后，在暴露于2,3,7,8-tetrachlorodibenzo-p-dioxin（dioxin）之后，最能认识在环境上，AHR被称为与异种二聚体伴侣（AHR核转运剂（ARNT）蛋白）结合的配体激活转录因子（XRE）。近年来，许多基因缺乏明确定义的XRE介导的基因expears，涉及其他机制，涉及XRE的特征良好的过程。 SUPPSSOR。结合和功能研究证实，AHR-KLF6复合物的NC-XRE结合与ARNT蛋白质无关。损伤后的正常肝脏再生，抑制G1相依赖性激酶（CDK）活性，特别是CDK2。 CDK2抑制剂的表达P21CIP1。。 AHR-KLF6特异性目标1描述NC-XRE蛋白DNA复合物的详细表征和功能分析。复杂的鉴定，这是我们对AHR生物学和TCDD Toxity的理解的范式转变。