REGULATION OF ETHANOL-INDUCIBLE CYTOCHROME P450 GENE

乙醇诱导细胞色素 P450 基因的调控

• 批准号: 3808628
• 负责人: B J SONG
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3808628
• 关键词: alcoholism /alcohol abuse; antibody formation; carbon tetrachloride; complementary DNA; cytochrome P450; diabetes mellitus genetics; enzyme induction /repression; enzyme mechanism; enzyme structure; enzyme substrate; ethanol; gene expression; genetic mapping; genetic regulation; genetic transcription; hormone regulation /control mechanism; human tissue; isozymes; laboratory rat; lymphocyte; messenger RNA; molecular cloning; molecular genetics; nucleic acid hybridization; nucleic acid sequence; pregnancy; tissue /cell culture; western blottings

As a continuous ongoing project, the molecular regulatory mechanism of P450IIE was further investigated. We have previously identified and determined the structures of the ethanol-inducible cytochrome P450 (P450IIEI) of both rat and human. We have also demonstrated three distinct types of regulation of P450IIE1 in rat. The three types of up-regulation of P450IIE appeared to be present in liver, lung, and kidney tissues. The mechanism of a negative effect of CCl4 on P450IIE was further examined. The administration of CCl4 not only reduced the level of P450IIE associated enzyme activity and the amount of immunoreactive P450llE, but also caused rapid decline in its mRNA indicating a pretranslational reduction of P450IIE by its own substrate. In contrast, other major classes of P450 did not appear to be affected by CCl4, indicating a specific reduction of P450IIE. In a collaboratory project with Dr. Casazza, a pretranslational reduction of P450IIE during pregnancy was also observed indicating a negative hormonal control mechanism in P450IIE regulation. The two specific down-regulations of P450IIE by CCl4 and hormones during pregnancy along with three types of up-regulatory mechanism of P450IIE thus provide an unique example of multiple modes of regulation among the classes of P450, most of which are activated by transcriptional activation. A method for the measurement of P450IIE1 in easily obtainable human tissues was also established. By immunoblot analysis, P450IIE1 expressed in cultured lymphocytes could be easily detected by specific antibody to P450IIE1. The levels of P450IIE in lymphocytes from poorly controlled diabetic children are elevated four to ten fold over those of the corresponding control subjects. The induced levels of P450IIEI determined by the density of immunoreactive bands highly correlated with those of hemoglobin Alc with a correlationship coefficient of 0.87. The levels of P450IIE in lymphocytes from alcoholic patients at admission and discharge were determined by the immunoblot analyses: the levels of P450IIE in alcoholics were four to five folds higher than those found in the voluntary control group.

作为一个持续进行的项目， P450IIE的进一步研究。我们之前已经确认， 确定了乙醇诱导的细胞色素P450的结构 （P450 IIEI）大鼠和人类。我们还展示了三种不同的 大鼠P450IIE1的调节类型三种类型的上调 P450 IIE似乎存在于肝、肺和肾组织中。的 进一步探讨了CCl_4对P450IIE负作用的机制。的 CCl4不仅降低了P450 IIE相关的水平， 酶活性和免疫反应性P450 11E的量，但也引起 其mRNA的快速下降表明其翻译前的减少， P450 IIE通过其自身底物。相比之下，其他主要类别的P450 似乎不受CCl4的影响，这表明特定的 P450IIE。在与Casazza博士的一个合作实验室项目中， 妊娠期间P450 IIE的减少也表明， P450IIE调节中的负性激素控制机制。的两个具体 妊娠期间CCl 4和激素对P450 IIE的下调作用沿着 P450 IIE的三种上调机制，从而提供了一种 P450类中多种调节模式的独特示例， 其中大部分是通过转录激活来激活的。 一种检测人体组织中P450 IIE1的方法 也成立了。通过免疫印迹分析，P450IIE1在人乳腺癌中表达， 培养的淋巴细胞可以很容易地被特异性抗体检测到， P450IIE1.正常对照组淋巴细胞P450 IIE水平 糖尿病儿童的发病率是正常儿童的4到10倍， 相应的控制对象。测定P450 IIEI的诱导水平 免疫反应带的密度与 血红蛋白Alc的相关系数为0.87。水平 酒精中毒患者入、出院时淋巴细胞P450IIE的检测 通过免疫印迹分析确定： 酗酒者比志愿者高出四到五倍。 对照组