MOLECULAR BIOLOGY OF NICOTINIC RECEPTORS

该中心提出了四个假设，以研究α - 7神经元烟碱乙酰胆碱受体基因（CHRNA7）遗传多态性在精神分裂症中的作用：(1)鉴定CHRNA7基因多态性与精神分裂症的关系，(2)在细胞水平上证明多态性表达的功能效应，(3)多态性与疾病相关的脑功能缺陷的关系，以及(4)通过针对CHRNA7引起的细胞功能障碍的治疗来逆转脑功能缺陷。本项目将解决假设1和假设2，为中心研究人员提供活体受试者和死后大脑的DNA基因分型，以及与诊断和功能的关联的体外评估。通过多项生物学和遗传学研究，CHRNA7已被选为染色体15q14连锁区最有可能的候选基因。在CHRNA7基因的近端启动子区域发现了与基因表达减少一致的功能性突变。这些都与精神分裂症和P50缺陷有关。在该基因的5'上游区域发现了额外的调控区域，其中包含多态性位点。在这个项目中，Aim 1将完成5'上游调控区域的基因分型，在来自连锁家系的10个先证中对该基因的剩余部分进行测序，并研究可能影响RNA剪接的相关内含子变异。在该区域的其他四个基因的snp将被检查为

The Center proposes four postulates for investigating the role of genetic polymorphism in the alpha7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) in schizophrenia: (1) identification and association of polymorphisms in CHRNA7 with schizophrenia, (2) demonstration of a functional effect of the polymorphism expression at the cellular level, (3) relation of the polymorphisms to deficits in brain function associated with the illness, and (4) reversal of the deficits in brain function by treatment directed at the cellular dysfunction caused by CHRNA7. This Project will address Postulates 1 and 2 by providing for the Center Investigators, genotyping of DNA from both live subjects and from postmortem brain, and in vitro evaluation of association with diagnosis and with function. CHRNA7 has been selected as the most likely candidate gene in the chromosome 15q14 linkage region by multiple biological and genetic studies. Functional mutations, consistent with reduced expression of the gene, were found in the proximal promoter region of the CHRNA7 gene. These are associated with both schizophrenia and the P50 deficit in the disease. Additional regulatory regions have been found in the 5' upstream region of the gene that contain polymorphic sites. This Project, Aim 1 will complete genotyping in 5' upstream regulatory regions, sequence the remaining sections of the gene in 10 probands from linked pedigrees, and investigate an associated intronic variant that may affect RNA splicing. SNPs in the four other genes in this region will be examined as well. As suggested by the Reviewers, we will also provide SNP genotyping for another gene with functional mutations, COMT, for association with schizophrenia and the phenotypes being investigated in this and other projects. For Postulate 2, Aim 2 will investigate the association of CHRNA7 mutations with CHRNA7 mRNA and protein expression in human postmortem brain of control and schizophrenic subjects. In Aim 3, we will further investigate the effects of CHRNA7 associated and functional mutations on the expression of other genes, utilizing microarray technology. The consequences of mutations in CHRNA7 on expression of CHRNA7, itself, and of other genes may have pathophysiological importance for the projects in the Center.