Research Project 5: Mechanism and Impacts of Dioxin Resistance in Fish

研究项目5：鱼类抗二恶英的机制和影响

• 批准号: 7799052
• 负责人: MARK HAHN
• 金额: $ 23.24万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至 2012-09-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7799052
• 关键词: ARNT gene; ARNT2 gene; Address; Agonist; Amino Acids; Animals; Aromatic Hydrocarbons; Aromatic Polycyclic Hydrocarbons; Aryl Hydrocarbon Receptor; Basic Science; Binding; Boston; CYP1A1 gene; Characteristics; Chemicals; Collaborations; Controlled Environment; Creosote; Cyprinodontidae; Development; Dioxins; EP300 gene; Embryo; Environment; Environmental Estrogen; Exhibits; Exposure to; Fishes; Frequencies; Fundulus heteroclitus; Gene Expression; Gene Frequency; Genes; Genetic; Genetic Polymorphism; Genetic Transcription; Genetic Variation; Grant; Haplotypes; Hepatocyte; Hypoxia; Hypoxia Inducible Factor; Individual; Link; Location; Long-Term Effects; Mammalian Cell; Mammals; Massachusetts; Measures; Modeling; Molecular; Oxidative Stress; Pathway interactions; Phenotype; Polychlorinated Biphenyls; Population; Population Genetics; Research; Research Project Grants; Resistance; Rivers; Signal Pathway; Signal Transduction; Single Nucleotide Polymorphism; Site; Superfund; Testing; Time; Toxic effect; Universities; Variant; Vertebrates; base; cDNA Arrays; cost; embryo cell; environmental stressor; in vivo; malformation; mortality; novel; programs; research study; response; stressor; superfund site

The overall objective of the basic research proposed here is to understand the effects of long-term, multigenerational exposure to high levels of contaminants on natural populations of animals inhabiting Superfund sites. We will employ a fish model species, the Atlantic killifish Fundulus heteroclitus, which have evolved resistance to dioxin-like compounds that act through the aryl hydrocarbon receptor (AHR) at numerous sites. Killifish inhabiting New Bedford Harbor (NBH), MA, a polychlorinated biphenyl (PCB)-contaminated Superfund site, exhibit heritable resistance to altered gene expression and toxicity of 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) and other AHR agonists as compared to fish from a reference site, Scorton Creek, MA (SC). We have identified and cloned two distinct AHRs (AHR1 and AHR2), ARNT2, hypoxia-inducible factors (HIFs), and an AHR represser (AHRR) in killifish. The killifish AHR1 gene is highly polymorphic and AHR1 allele frequencies differ between populations of dioxin-sensitive (SC) and dioxin-resistant (NBH) fish. The studies proposed here will build on these previous findings to address ecological and biomedical/mecham'stic questions regarding the impact of chemicals at Superfund sites. The major objectives are 1) to understand mechanisms underlying differential sensitivity to the developmental toxicity of HAHs and PAHs that act through AHR-dependent signaling, and 2) to determine the impact of evolved HAH/PAH resistance on the sensitivity to other environmental stressors. The first objective will be achieved by focusing on population genetic and functional aspects of polymorphisms in AHR-pathway genes (Aims 1 & 2). The second objective will be approached by focusing on responses to environmental hypoxia (Aim 3). Specific Aims are: (1) To compare polymorphism (SNP) and haplotype frequencies at the AHR1, AHR2, AHRR, and ARNT2 loci in dioxin-sensitive and -resistant populations of killifish, (2) To determine the association of specific AHR1, AHR2, AHRR, or ARNT2 variants with the resistance phenotype of individual fish and to determine the functional differences among variants, and (3) To assess the impact of the dioxin-resistant phenotype on sensitivity to environmental hypoxia and determine the mechanistic basis for cross-talk between dioxin and hypoxia signaling pathways. The proposed research will take advantage of a unique opportunity to establish the molecular mechanisms of population-level effects of contaminants on a natural population of vertebrate animals inhabiting a Superfund site.

这里提出的基础研究的总体目标是了解长期的、多代的 超级基金中栖息的动物自然种群暴露于高水平污染物 网站.我们将采用一种鱼类模式物种，大西洋鳉Fundulus heteroclitus， 对二恶英类化合物的抗性，这些化合物通过芳香烃受体（AHR）在许多位点起作用。 栖息在马萨诸塞州新贝德福德港（NBH）的刀鱼，多氯联苯（PCB）污染 超级基金网站，表现出遗传抗性改变基因表达和毒性的2，3，7，8- 四氯二苯并-对-二恶英（TCDD）和其他AHR激动剂与来自参考地点的鱼类相比， 马萨诸塞州斯科顿克里克（南卡罗来纳州）。我们已经鉴定并克隆了两种不同的AHR（AHR 1和AHR 2），ARNT 2， 鳉鱼中的缺氧诱导因子（HIFs）和AHR抑制因子（AHRR）。Killifish AHR 1基因 高度多态性和AHR 1等位基因频率在二恶英敏感（SC）和 抗二恶英（NBH）鱼类。这里提出的研究将建立在这些以前的发现，以解决 关于超级基金场址化学品影响的生态和生物医学/机械问题。的 主要目标是：1）了解对发育敏感性差异的机制 通过AHR依赖信号作用的HAHS和PAH的毒性，以及2）确定 进化的HAH/PAH抗性对其他环境应激因素的敏感性。第一个目标是 通过关注AHR途径基因多态性的群体遗传学和功能方面来实现 (Aims 1和2）。第二个目标将通过关注对环境缺氧的反应来实现 (Aim 3）。具体目的是：（1）比较AHR 1的多态性（SNP）和单倍型频率， AHR 2、AHRR和ARNT 2基因座在二氧杂环己烷敏感和抗性群体中的分布 特异性AHR 1、AHR 2、AHRR或ARNT 2变异体与以下耐药表型的关联： 个体鱼，并确定变异体之间的功能差异，以及（3）评估 二恶英抗性表型对环境缺氧敏感性的研究，并确定其机理基础 二恶英和缺氧信号通路之间的串扰。拟议的研究将利用 这是一个独特的机会，建立污染物对环境的群体水平影响的分子机制。 栖息在超级基金地点的脊椎动物的自然种群。