Human Dopamine Transporter Gene: Variation and Transcriptional Regulation

描述（由申请人提供）：该提案的总体目标是剖析人类多巴胺转运蛋白基因（hDAT）中的转录机制。多巴胺转运蛋白（DAT）通过多巴胺的再摄取和释放来调节多巴胺神经传递的时空域，从而有助于运动、动机、认知和注意力、工作记忆、行为组织和激素释放。众所周知，大脑中 DAT 基因的表达受到高度限制，在个体受试者之间存在差异，并且可以受到内源性和外源性因素（例如可卡因滥用）的调节。 DAT 表达的改变可能导致 hDAT 相关的病理生理状态，例如药物滥用。然而，关于 hDAT 表达如何调节以及 DNA 序列变异如何影响调节表达的信息仍然零星。本提案要检验的假设是转录拮抗作用在调节 hDAT 活性中发挥重要作用。我们的初步研究表明，整个基因中的不同顺式作用元件表现出增强或沉默活性。因此，该项目的两个具体目标是：1）证明顺式作用元件之间的转录拮抗作用及其与hDAT表达的相关性； 2) 鉴定与顺式作用结合的转录因子 人类死后脑组织中 hDAT 启动子周围的元件。这些结果将增加关于先导位点的基础知识，hDAT 通过这些位点受到包括滥用药物在内的外部因素的调节，并带来相关脑部疾病的风险。

DESCRIPTION (provided by applicant): The overall goal of this proposal is to dissect transcription mechanisms in the human dopamine transporter gene (hDAT). The dopamine transporter (DAT) regulates the spatio-temporal domains of dopamine neurotransmission by reuptake and release of dopamine and thus contributes to locomotion, motivation, cognition and attention, working memory, behavioral organization and hormone release. It is well recognized that expression of the DAT gene in the brain is highly circumscribed, varies among individual subjects and can be regulated by endogenous and exogenous factors such as cocaine abuse. Altered DAT expression may contribute to hDAT-associated pathophysiological states such as substance abuse. However, information about how hDAT expression is regulated and how DNA sequence variation influences the regulated expression remains sporadic. The hypothesis to be tested in this proposal is that transcriptional antagonisms play a major role in regulating hDAT activity. Our preliminary studies show that different cis-acting elements across the entire gene display either enhancing or silencing activities. Therefore, two specific aims of this project are to: 1) demonstrate transcriptional antagonisms between the cis-acting elements and their correlation with hDAT expression; and 2) identify transcription factors that bind to the cis-acting elements around the hDAT promoter in human postmortem brain tissues. The results will add fundamental knowledge on lead sites through which hDAT is regulated by external factors including drugs of abuse and confers risks for related brain disorders.