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。从长期给药的大鼠伏隔核（NA）中分离差异表达基因可能有助于了解乙醇成瘾发生和强化的潜在分子机制。根据差异显示，无论乙醇是否直接影响NA中的基因表达，还是乙醇对神经元活性的改变是继发的，NA中约0.1%的mRNA被认为受到慢性乙醇给液的影响。通过反向Northern blot分析，筛选出46个成功重新扩增的克隆，分离到8个上调基因和7个下调基因。其中一个上调的cDNA与人tgf - β1同源，在小脑和LC中也有优先表达。由于克隆c10在乙醇介导的NA中表现出极优先的表达，因此对其上游序列进行了5'RACE分析，但编码序列尚未分离。c118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，其缺失会导致髓鞘发育异常，因此其上调可能对乙醇诱导的髓鞘发育异常起保护作用。另外12个cdna被注册为est或novel，因此其功能未知。鉴定它们的上游序列，包括编码区和启动子序列，不仅可以估计这些差异表达基因在乙醇依赖中的作用，而且可以澄清是否存在乙醇依赖基因调控。

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.