Genetic variations of promoter sequences of aldehyde dehydrogenase and individual differences of alcohol metabolism

为了阐明酒精代谢的个体差异及其影响，本研究对启动子区域进行了分析。分离慢性乙醇给药大鼠中脑核（NA）中差异表达的基因可能有助于了解乙醇成瘾发展和强化的潜在分子机制。根据差异显示，约0.1%的mRNA被认为是受慢性乙醇管理的NA，无论乙醇是否直接影响基因表达的NA或基因改变是继发于乙醇神经元活动的改变。对其中的46个克隆进行反向北方杂交分析，筛选出8个表达上调的基因和7个表达下调的基因。其中一个上调的cDNA与人TGFβ1-同源，并且在小脑和LC中也观察到其优先表达。由于克隆c10在乙醇处理的NA中显示出极优先的表达，因此用5 'RACE分析了其上游序列，但尚未分离其编码序列。c118在乙醇诱导的NA中富集，与小鼠KH结构域RNA结合蛋白QKI-5A具有高度同源性，5 'RACE分析证实该克隆编码大鼠QKI-5A。由于QKI蛋白被认为是髓鞘形成的调节因子，其缺失导致髓鞘形成障碍，其上调可能对乙醇诱导的髓鞘形成障碍具有保护作用。另外12个cDNA已登记为EST或新的，因此其功能尚不清楚。因此，鉴定这些差异表达基因的上游序列，包括编码区和启动子序列，不仅可以推测这些差异表达基因在乙醇成瘾中的作用，而且可以明确乙醇依赖性基因调控是否存在。

To elucidate the individual differences of alcohol metabolism and effects, the promoter regions were analyzed in the present study. To isolate differentially expressed genes in the nucleus accumbens (NA) from chronically ethanol-administered rats may help understand underlying molecular mechanisms for development and reinforcement of ethanol addiction. According to differential display around 0.1% of mRNA was considered to be affected by chronic ethanol-administration in the NA, regardless whether ethanol directly affected gene expression in the NA or gene alteration was secondary to alteration in neuronal activity by ethanol. Among them, 46 clones successfully re-amplified were screened by reverse Northern blot analysis and 8 up-regulated and 7 down-regulated genes were isolated. One of the up-regulated cDNA was homologous to human TGFβ1-and its preferential expression was also observed in the cerebellum and LC.Since clone c10 displayed extremely preferential expression in the ethanol-administered NA, its upstream sequence was analyzed by 5'RACE but the coding sequence was not yet isolated. c118 was enriched in the ethanol-administered NA and displayed high homology to mouse KH domain RNA binding protein QKI-5A.The 5'RACE analysis confirmed that this clone encoded rat QKI-5A.Since QKI proteins are considered to be regulators of myelination and their absence causes dysmyelination, its up-regulation may play a protect role against ethanol-induced dysmyelination. Other 12 cDNAs were registered as ESTs or novel so that their functions were unknown. It seems important to identify their upstream sequences including coding regions and promoter sequences not only to estimate the roles in ethanol addiction of these differentially expressed genes but also to clarify whether ethanol-dependent gene-regulation exists or not.