Human Dopamine Transporter Gene: Variation and Transcriptional Regulation

描述（由申请人提供）：本提案的总体目标是剖析人类多巴胺转运蛋白基因（hDAT）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、工作记忆、行为组织和激素释放。众所周知，DAT基因在脑中的表达是高度限制的，在个体受试者之间变化，并且可以受到内源性和外源性因素如可卡因滥用的调节。DAT表达改变可能导致hDAT相关的病理生理状态，如药物滥用。然而，关于hDAT表达如何被调节以及DNA序列变异如何影响被调节的表达的信息仍然是零星的。在这个建议中要测试的假设是，转录拮抗剂在调节hDAT活性中起主要作用。我们的初步研究表明，不同的顺式作用元件在整个基因显示增强或沉默活动。因此，本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）鉴定与顺式作用元件结合的转录因子。 人死后脑组织中hDAT启动子周围的元件。这些结果将增加对hDAT受外部因素（包括滥用药物）调节的主要部位的基本知识，并赋予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.