ROLE OF ALDH2--TRANSGENIC MICE CARRYING ASIAN ALDH2-2 VARIANT ALLELE

线粒体乙醛脱氢酶 ALDH 2是参与乙醛合成的主要ALDH同工酶 新陈代谢.众所周知，单个核苷酸 导致氨基酸变化的取代（G至A） （Glu 487 Lys）导致ALDH 2活性的显性失活。 我们的数据表明，重组人ALDH 2变体 与小鼠ALDH 2蛋白相互作用的蛋白， 抑制了小鼠酶的活性。遗传 多态性是引起潮红反应的原因， 许多亚洲人饮酒后。虽然 ALDH 2 -2等位基因已被证明具有保护作用， 酒精中毒，这种酶的生理作用尚不清楚。到 进一步研究ALDH 2在 酒精介导的组织损伤、饮酒行为和代谢 内源和外源底物，我们生产了转基因 携带人ALDH 2变体（Haldh 2 -2）的小鼠。目前我们 建立了两个独立的Haldh 2转基因小鼠系。 人ALDH 2蛋白在所有检查的组织中表达， 人ALDH 2 -2的表达抑制小鼠ALDH 2酶 转基因小鼠的活性。我们还观察到，FVB/N 背景品系小鼠表现出恐惧、回避和逃避 20%乙醇处理后3天， 在暴露于以下物质的转基因小鼠中， 乙醇组（P<0.001）。为了将明显的行为变化 与神经递质水平，并研究ALDH 2在 内源性代谢，各种单胺水平 神经递质通过HPLC测定。我们的数据还 表明雄性和雌性转基因小鼠均显示40-50% 肝脏中的乙醛水平高于FVB/N背景 小鼠（每组n=6，p<0.01）。我们正在确定 两瓶酒选择模式下的饮酒偏好。我们的数据 迄今为止收集的数据表明，携带Haldh 2 -2的转基因小鼠 可以成为研究ALDH在行为中作用的有价值的模型， 神经递质代谢和饮酒偏好。为了 对于ALDH 2的生理作用有明确的结果，我们有 还制备了DNA载体，以制备缺乏 小鼠ALDH 2基因的表达。

The mitochondrial aldehyde dehydrogenase (ALDH2) is the major ALDH isozyme involved in acetaldehyde metabolism. It is well established that a single nucleotide substitution (G to A) which results in the amino acid change (Glu487Lys) leads to dominant inactivation of ALDH2 activity. Our data indicated that the recombinant human ALDH2 variant protein interacted with the mouse ALDH2 protein and dominantly inhibited the activity of the mouse enzyme. The genetic polymorphism is the cause of the flushing response observed in many Asian people following alcohol intake. Although the ALDH2-2 allele has been shown to have a protective role against alcoholism, the physiological role of this enzyme is still unclear. To further examine the physiological role of ALDH2 in alcohol-mediated tissue damage, drinking behavior and metabolism of endogenous and exogenous substrates, we produced transgenic mice carrying the human ALDH2 variant (Haldh2-2). Currently, we have established two independent lines of Haldh2 transgenic mice. Human ALDH2 protein was expressed in all tissues examined and expression of human ALDH2-2 inhibited mouse ALDH2 enzyme activity in transgenic mice. We also observed that the FVB/N background strain mice showed fear, avoidance and escape behavior 3 days after treatment with 20% ethanol but these changes in behavior were not evident in the transgenic mice exposed to ethanol (p<0.001). To correlate the apparent behavioral change with levels of neurotransmitters and to study the role of ALDH2 in endobiotic metabolism, the levels of various monoamine neurotransmitters are being determined by HPLC. Our data also indicate that both male and female transgenic mice showed 40-50% higher acetaldehyde levels in the livers than the FVB/N background mice (n=6 for each group, p<0.01). We are determining the drinking preference in a two-bottle choice paradigm. Our data collected so far indicate that transgenic mice carrying the Haldh2-2 can be a valuable model to study the role of ALDH in behavior, neurotransmitter metabolism and drinking preference. In order to have clear results for the physiological roles of ALDH2, we have also prepared a DNA vector to prepare knock-out mice deficient of mouse ALDH2 gene by gene disruption method.