Genetic Determinants of COMT Expression

COMT 表达的遗传决定因素

• 批准号: 7091730
• 负责人: Steven P. Hamilton
• 金额: $ 17.23万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7091730
• 关键词: alleles; behavioral genetics; biotechnology; catechol methyltransferase; cell line; clinical research; enzyme activity; enzyme induction /repression; estrogens; family genetics; gene expression; genetic markers; genetic regulation; genetic regulatory element; genetic screening; genetic susceptibility; human genetic material tag; human tissue; neural transmission; neuropharmacology; protein isoforms; psychopathology; single nucleotide polymorphism

DESCRIPTION (provided by applicant): Catechol-O-methyltransferase, COMT, metabolizes endogenous catechol substrates, and thus is important in a variety of processes, including neurotransmission. Dysregulation of catechol levels is implicated in neurobehavioral disorders. Numerous genetic association studies suggest the involvement of COMT in brain diseases like schizophrenia and panic disorder. Many of these allelic associations involve a functional COMT DNA that alters enzymatic activity. These association results are often contradictory and implicate another variant or variants at or near the COMT locus. Additionally, allele-specific mRNA expression using this functional COMT variant has been observed. This proposal outlines a feasibility study to characterize the DNA sequence and expression variation in individuals in an effort to understand the potential impact of sequence variation on COMT expression in a disease population. We hypothesize that DNA variation in the catechol-O-methlytransferase gene region contributes to variability in COMT mRNA expression. In order to test this hypothesis, we will use lymphoblastoid cell lines from 30 Caucasian CEPH trios from Utah, a population that has been genotyped by the HapMap Consortium in order to characterize genetic diversity in the human population. With this population, we will characterize cell line COMT mRNA expression using quantitative reverse transcription-polymerase chain reaction. For subjects heterozygous for DNA variants present in transcripts, we will measure allele-specific mRNA expression using a single base extension method. We will then test the correlation between genotype and mRNA expression variation in COMT. We will genotype our sample for common single nucleotide polymorphisms (SNPs) within the COMT locus and across a region approximately 340kb upstream of COMT, as well as use genotypes from ~100 SNPs already genotyped in this same sample in this same region during the HapMap project. Single markers and multiple-marker haplotypes will be used to test for correlation with variation in mRNA expression. Finally, we will exploit observations of the regulatory role that estrogen plays in COMT activity by assessing COMT expression after treating cell lines with estrogen, and then measuring association to SNP genotypes, including variants in predicted estrogen response elements. Genetic polymorphisms correlated with differences in COMT expression can be used to identify cis- acting regulatory elements for predicting COMT functional differences. This in vitro work may be useful for the understanding of the genetic contribution of COMT to disease susceptibility, particularly with regard to the cis regulation of the COMT locus.

描述（由申请人提供）：儿茶酚-O-甲基转移酶，COMT，代谢内源性儿茶酚底物，因此在包括神经传递在内的多种过程中很重要。儿茶酚水平失调与神经行为障碍有关。大量遗传关联研究表明 COMT 与精神分裂症和恐慌症等脑部疾病有关。许多等位基因关联涉及改变酶活性的功能性 COMT DNA。这些关联结果通常是矛盾的，并且暗示 COMT 基因座处或附近的另一个或多个变体。此外，还观察到使用这种功能性 COMT 变体的等位基因特异性 mRNA 表达。该提案概述了一项可行性研究，旨在描述个体 DNA 序列和表达变异的特征，以了解序列变异对疾病群体中 COMT 表达的潜在影响。我们假设儿茶酚-O-甲基转移酶基因区域的 DNA 变异导致 COMT mRNA 表达的变异。为了检验这一假设，我们将使用来自犹他州 30 个高加索 CEPH 三人组的淋巴母细胞系，该群体已由 HapMap 联盟进行基因分型，以表征人类群体的遗传多样性。对于这个群体，我们将使用定量逆转录聚合酶链式反应来表征细胞系 COMT mRNA 表达。对于转录本中存在 DNA 变异杂合的受试者，我们将使用单碱基延伸方法测量等位基因特异性 mRNA 表达。然后我们将测试 COMT 基因型和 mRNA 表达变异之间的相关性。我们将对 COMT 基因座内和 COMT 上游约 340kb 区域内的常见单核苷酸多态性 (SNP) 样本进行基因分型，并使用在 HapMap 项目期间已在同一区域的同一样本中进行基因分型的约 100 个 SNP 的基因型。单标记和多标记单倍型将用于测试与 mRNA 表达变异的相关性。最后，我们将通过评估用雌激素处理细胞系后的 COMT 表达来观察雌激素在 COMT 活性中发挥的调节作用，然后测量与 SNP 基因型的关联，包括预测的雌激素反应元件中的变异。与COMT表达差异相关的遗传多态性可用于鉴定顺式作用调节元件以预测COMT功能差异。这项体外工作可能有助于了解 COMT 对疾病易感性的遗传贡献，特别是 COMT 基因座的顺式调控。