Conserved AHR-dependent control of Sox9 long non coding RNA expression

Sox9 长非编码 RNA 表达的保守 AHR 依赖性控制

• 批准号: 8884471
• 负责人: Robyn L Tanguay
• 金额: $ 21.81万
• 依托单位: OREGON STATE UNIVERSITY
• 依托单位国家: 美国
• 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/8884471
• 关键词: Address; Affect; Animals; Aryl Hydrocarbon Receptor; Benz(a)Anthracenes; Binding; Bioinformatics; Biological Process; Chemicals; Clustered Regularly Interspaced Short Palindromic Repeats; Complex; Congenital Abnormality; Coupled; Data; Development; Disease; Down-Regulation; Embryonic Development; Environmental Pollution; Enzymes; Event; Exploratory/Developmental Grant; Exposure to; Fishes; Gene Expression; Gene Targeting; Genes; Genetic Transcription; Genomics; Goals; High-Throughput Nucleotide Sequencing; Homeostasis; Human; Human Development; Immune system; In Situ Hybridization; Inflammation; Knock-out; Knowledge; Ligands; Mammals; Maps; Mediating; Messenger RNA; Modeling; Molecular Toxicology; Mus; Organ; Outcome; Pathway interactions; Positioning Attribute; Quinones; RNA; RNA Binding; RNA analysis; Receptor Activation; Receptor Signaling; Regulation; Regulatory Element; Relative (related person); Reporter; Reporting; Research; Role; Signal Pathway; Signal Transduction; Site; Structure; System; Testing; Tetrachlorodibenzodioxin; Therapeutic Uses; Toxic Environmental Substances; Toxic effect; Toxicology; Transcript; Transcriptional Regulation; Treatment Efficacy; Untranslated RNA; Xenobiotics; Zebrafish; activating transcription factor; adverse outcome; aryl hydrocarbon receptor ligand; benzanthracene; beta catenin; cell type; craniofacial; developmental toxicity; gene repression; genome editing; genome-wide analysis; human disease; immune function; improved; in vivo; innovation; loss of function; men; novel; novel strategies; overexpression; progenitor; promoter; public health relevance; reproductive; research study; response; tool; transcription factor; transcriptome sequencing; tumor

 DESCRIPTION (provided by applicant): Since the discovery of the Aryl Hydrocarbon Receptor (AHR) 20 years ago, it is clear that this ligand activated transcription factor is intimately integrated with numerous signaling pathways that modulate biological processes. Exposure to AHR ligands profoundly impacts embryonic development, immune function, and promote tumor development. It has been implicated in multiple human diseases. Furthermore, selective AHR modulators are now being developed for therapeutic uses to suppress inflammation. Elucidating the complex events immediately downstream of AHR activation is critical to parse toxicity and improve therapeutic efficacy. The bulk of research into the downstream AHR targets has focused on mRNA induction, despite ample evidence that numerous transcripts are repressed by AHR activation. One key down-regulated target is sox9, a transcription factor that controls specification and differentiation of numerous progenitor and differentiated cell types. Sox9 haploinsufficiency causes a multitude of severe developmental problems in humans, but the mechanisms governing sox9 transcription remain unsolved. We and others have reported that TCDD leads to a rapid down regulation of sox9 transcription in an AHR dependent mechanism in developing mammals and fish, which is manifest through craniofacial and reproductive effects. Understanding the mechanisms of AHR- dependent transcriptional repression of sox9b has stymied us for six years, until we completed an unbiased deep RNA-seq study that identified a novel long non-coding RNA (lncRNA) transcript induced by developmental exposure to AHR ligands. This lncRNA is directly adjacent to the sox9b gene. Importantly the lncRNA-sox9b genomic relationship is conserved in mice and humans. We hypothesize a new adverse outcome pathway whereby AHR activation induces sox9b-lncRNA which in turn down-regulates sox9b transcription. Using AHR2-null fish, we confirmed that the sox9b-lncRNA induction is absolutely AHR2-dependent. We also identified AHR regulatory elements in the promoters of both zebrafish and mammalian lncRNA-sox9b genes. To test the hypothesis that the conserved sox9-lncRNA is a direct AHR target gene that upon AHR activation represses sox9b leading to target organ-specific toxicity, we will complete two Specific Aims: 1) We will determine the temporal and spatial expression of zebrafish sox9b-lncRNA relative to the sox9b mRNA, determine its binding to the sox9b promoter in vivo, and identify other potential targets of the sox9b-lncRNA by genome-wide analysis; 2) Using sox9b-lncRNA gain and loss-of-function studies, we will also define the role of sox9b-lncRNA in AHR-dependent developmental toxicity. Collectively, these studies are ideal for the R21 mechanism to build the new tools need to probe the role of lncRNAs in toxicity and develop a new approach for unraveling an unexpected layer of complexity affecting adverse outcome pathways.

 描述（由申请人提供）：自从 20 年前发现芳基烃受体 (AHR) 以来，很明显，这种配体激活的转录因子与调节生物过程的众多信号通路紧密结合，暴露于 AHR 配体会对胚胎产生深远的影响。此外，选择性 AHR 调节剂目前正在开发用于抑制炎症的治疗用途。尽管大量证据表明 AHR 激活抑制了许多转录物，但 AHR 激活的下游对于解析毒性和提高治疗效果至关重要。 Sox9 单倍体不足是一种控制多种祖细胞和分化细胞类型的转录因子，会导致人类出现多种严重的发育问题，但控制 sox9 转录的机制仍未得到解决。在发育中的哺乳动物和鱼类中，TCDD 会导致 AHR 依赖性机制中 sox9 转录的快速下调，这通过颅面和生殖效应表现出来。对 sox9b 的 AHR 依赖性转录抑制机制的理解已经阻碍了我们六年，直到我们了解为止。完成了一项无偏见的深度 RNA 测序研究，该研究鉴定了一种新的长非编码 RNA (lncRNA) 转录物，该转录物是由发育暴露于 AHR 配体诱导的，该 lncRNA 与 AHR 配体直接相邻。 sox9b 基因。 sox9b-lncRNA 诱导绝对依赖于 AHR2。我们还在斑马鱼和哺乳动物的启动子中发现了 AHR 调控元件。 lncRNA-sox9b 基因。为了测试保守的 sox9-lncRNA 是直接 AHR 靶基因，在 AHR 激活后抑制 sox9b 导致靶器官特异性毒性的假设，我们将完成两个具体目标：1）我们将确定时间和时间。斑马鱼 sox9b-lncRNA 相对于 sox9b mRNA 的空间表达，确定其在体内与 sox9b 启动子的结合，并确定该基因的其他潜在靶标通过全基因组分析来分析 sox9b-lncRNA；2) 利用 sox9b-lncRNA 功能获得和丧失的研究，我们还将定义 sox9b-lncRNA 在 AHR 依赖性发育毒性中的作用。构建新工具的机制需要探索lncRNA在毒性中的作用，并开发一种新方法来揭示影响不良结果途径的意想不到的复杂性。