MECHANISMS OF ETHANOL TOXICITY IN DICTYOSTELIUM

为了了解乙醇对人类的影响，我们必须首先确定乙醇毒性的分子靶点。这些分子将成为酒精中毒遗传易感性诊断和酒精相关疾病治疗研究的主要候选者。本提案的广泛目标是通过遗传筛选的方法在模式生物盘状盘齿龙中确定乙醇毒性的分子靶点。cAMP信号转导是哺乳动物乙醇毒性的可能靶点之一，而介导cAMP信号转导的分子机制在进化分歧生物之间高度保守。和人类一样，盘基钢菌的cAMP信号对乙醇的作用很敏感。然而，盘基ostelum的遗传研究远没有其他生物复杂，部分原因是cAMP信号转导机制对于生长是必不可少的。这提供了一个强大的遗传模型，其中cAMP信号基因可以通过删除，过表达和其他突变来操纵。基因操作的后果可以监测多细胞发育和孢子萌发的变化，这些过程高度依赖于cAMP信号转导。本研究的实验目的是确定盘基钢菌cAMP信号传导中的已知基因是否与乙醇毒性相关，并选择具有改变乙醇敏感性的新突变体。在对相关基因进行鉴定和鉴定后，人类同源基因将被克隆并在突变的盘基骨柱细胞中表达。人类基因中补充乙醇相关突变的盘基骨菌可能是乙醇毒性的分子靶点。表达人类基因的盘基钢丝菌菌株可能为今后的人类研究提供一个方便的实验模型。

In order to understand the effects of ethanol on humans we must first identify the molecular targets for ethanol toxicity. These molecules will be prime candidates for the diagnosis of genetic predisposition to alcoholism and for investigations into therapy for alcohol-related disorders. The broad objective of this proposal is to identify molecular targets for ethanol toxicity by means of genetic screens in the model organism Dictyostelium discoideum. cAMP signal transduction is one of the likely targets for ethanol toxicity in mammals, and the molecular mechanisms that mediate cAMP signaling are highly conserved between evolutionary divergent organisms. In Dictyostelium, as in humans, cAMP signaling is sensitive to the effects of ethanol. However, genetic studies in Dictyostelium are far less complicated then in other organisms, partly because the cAMP signal transduction mechanism is dispensable for growth. This provides a powerful genetic model in which cAMP signaling genes can be manipulated by deletion, over expression, and other mutations. Consequences of the genetic manipulations can be monitored as changes in multicellular development and in spore germination, processes that are highly dependent on cAMP signal transduction. The experimental goals of this proposal are to determine whether known genes in Dictyostelium cAMP signaling are relevant targets for ethanol toxicity, and to select for new mutants with altered ethanol sensitivity. Following identification and characterization of the relevant genes, human homologs will be cloned and expressed in mutants Dictyostelium cells. Humans genes that complement ethanol related mutations in Dictyostelium are likely to be molecular targets for ethanol toxicity. Dictyostelium strains that express the human genes may provide a convenient experimental model that will facilitate future studies in humans.