【作者】 杨靖；

【导师】 汪道文；

【作者基本信息】 华中科技大学 ， 心血管内科， 2006， 硕士

【摘要】 目的花生四烯酸由细胞色素P450ω-羟化酶催化生成的19-和20-羟烷四烯酸（19-,20-HETE）,通过阻断Ca²⁺激活的K⁺通道而使血管平滑肌去极化,产生强有力的血管收缩作用。在血管平滑肌细胞中19-和20-HETE的生成可由血管紧张素Ⅱ、内皮素和去甲肾上腺素刺激,被一氧化氮所抑制。在肾脏可收缩微血管,抑制Na⁺-K⁺-ATP酶的活性及近曲小管的钠转运,调节水钠重吸收。在多种疾病过程,尤其是高血压病中,扮演着重要角色。编码生成该酶的基因——CYP4A11和CYP4F2已成为研究高血压病新的候选基因。而对这两个基因的结构及多态性情况,尤其是与心血管疾病的联系,知之甚少。寻找人群中这两个基因编码区的多态性位点分布情况,可以为研究高血压病的基因机制提供新的依据。方法采集50例血压正常、无血缘关系的汉族人外周静脉血白细胞;提取基因组DNA;设计特异性引物,PCR法分段扩增基因编码区序列,电泳检测后回收目的片断;测序,与参考序列比对后统计结果。结果CYP4A11共发现16个多态性位点,其中5个有意义:1个5’端非编码区的突变位点A-54G,4个引起氨基酸改变的多态性位点,分别为A6890C、A7207G、T7394A和T8590C ; CYP4F2共检测到6个多态性位点,其中3个有意义:1个为3’端非编码区的多态性位点G19026A,2个引起氨基酸改变的多态性位点T2013G和G18000A。其余均为内含子区或者同义突变。结论1.多态性位点存在种族差异;2.突变位点大多数位于内含子区,或者为同义突变,仅有少数有意义;3.发现的多态性位点可能引起蛋白质构象进而改变蛋白质功能,或者引起基因转录活性的改变,并为下面的蛋白质组学研究和大样本人群研究奠定了基础。更多还原

【Abstract】 Objective Arachidonic acid Cytochrome P450 （CYP）ω-hydroxylases catalyze arachidonic acid to produce 19- and 20-HETE, especially the later. 19- and 20-HETE depolarize VSM by blocking the open-state probability of Ca²⁺-activated K⁺-channels. The formation of 19- and 20-HETE in vascular smooth muscle is enhanced by angiotensin II, endothelin and norepinephrine and is attenuated by nitric oxide （NO）. 20-HETE plays an important role in the regulation of sodium reabsorption in renal tubules. 20-HETE inhibits Na⁺-K⁺-ATPase activity and sodium transport in proximal tubule. Additionally, 20-HETE may involve in a variety of pathophysiological conditions, especially primary hypertension. CYP4A11 and CYP4F2 became new interesting genes for hypertension, though we know little about them. Identification of characteristics single nucleotide polymorphisms （SNPs） existing in coding region of these genes may provide some new insights into the genetic mechanisms of hypertension.Method Genomic DNA was extracted from blood white cells of 50 unrelated Chinese Han people with normotension. The coding regions were amplified by PCR, respectively. After sequenced, the information wan aligned and summarized.Results Sixteen SNP sites in CYP4A11 were identified,in which there are 5 sense mutation, including A-54G in 5’-uncoding region, A6890C, A7207G, T7394A and T8590C , which caused corresponding amino acid changing （K-T, S-G, F-Y and F-S）, respectively. And in CYP4F2 three of six SNP sites were sense, including G19026A in 3’uncoding region, T2013G and G18000A causing amino substitute （V-G and V-M） , respectively. Others were in intron region or synonymous.Conclusion This study suggests that multiple variants exist within or near the CYP4A11 and CYP4F2 genes in Chinese populations. Most of variants were nonsense or in intron region. These SNPs or variants may change biologicalactivity ofω-hydroxylases. It may provide some directions for protein research consequently.更多还原