TOXICOLOGICAL CONTROL MECHANISMS OF HUMAN CYP1A2 GENE

包括多环在内的化学类别的外源化合物的毒性 芳香烃(PAH)和卤代烃，如 多氯联苯和二苯二恶英，很可能是通过 基因表达的控制。其分子机制在很大程度上是未知的， 但目前被认为部分涉及胞质受体，即 芳基碳氢化合物或芳基受体。如果对许多人负责的机制 与这些类别的化学品有关的毒性影响将是 解开后，有必要研究其他可能受到调控的基因 通过额外的细胞介体。这项拨款建议的重点是 人细胞色素P4501A2基因(CYP1A2)--PAH诱导型基因 CYP1A基因家族，在人类肝脏中占主导地位，并代谢药物， 例如扑热息痛、咖啡因、芳香胺等环境制剂 和饮食成分，如杂环胺和黄曲霉毒素。这个 人类CYP1A2基因调控的分子机制将是 通过顺式作用元素的表征和 利用瞬时转染法鉴定反式作用因子 分析和体外DNA结合分析，如DNase I足迹。在……里面 将进行人体原代肝细胞的活体足迹研究 为了检查转录因子之间的时间关系，在 调控细胞色素P1A2基因的表达。将使用几个模型系统 对于拟议的研究，包括人类肝癌细胞系，人类 人肝细胞和非增殖性肝细胞培养。A细胞培养 核心和人体组织银行将为这些项目提供必要的支持 学习。人们认为，这些分子和细胞的组合 文化方法将阐明这一重要的 基因是受调控的。

Toxicity of the chemical class of xenobiotics that include polycyclic aromatic hydrocarbons (PAH) and halogenated hydrocarbons, such as polychlorinated biphenyls and dibenzodioxins, most likely occurs through control of gene expression. The molecular mechanism is largely unknown, but is currently believed to involve, In part, a cytosolic receptor, the aryl hydrocarbon or Ah-receptor. If the mechanism responsible for the many toxic effects associated with these classes of chemicals is to be unraveled, it will be necessary to study other genes that may be regulated through additional cellular mediators. This grant proposal focuses on the human cytochrome P4501A2 gene (CYP1A2), a member of the PAH-inducible CYP1A gene family that is prominent in human liver, and metabolizes drugs, such as acetaminophen, caffeine, environmental agents such as arylamines and dietary constituents, such as heterocyclic amines and aflatoxins. The molecular mechanism for the regulation of the human CYP1A2 gene will be studied through the characterization of cis-acting elements and identification of trans-acting factors utilizing transient transfection assays and in vitro DNA binding assays, such as DNase I footprinting. In vivo footprinting studies in human primary hepatocytes will be conducted to examine the temporal relationship among transcription factors in regulating CYP1A2 gene expression. Several model systems will be utilized for the proposed research, including human hepatoma cell lines, human liver and non-proliferating cultures of human hepatocytes. A Cell Culture Core and Human Tissue Bank will provide the necessary support for these studies. It is believed that a combination of these molecular and cell culture approaches will elucidate the mechanism by which this important gene is regulated.