MOLECULAR GENETICS OF LOW RENIN HYPERTENSION

描述：(改编自申请者摘要)：佩林·怀特博士 希望继续研究基因异常的作用 编码醛固酮合成酶和11-羟基类固醇脱氢酶 在人类高血压发展过程中的活动。他之前已经 证明了细胞色素P11B1(类固醇11- 羟基酶)和CYP11B2(醛固酮合成酶)基因可以产生 具有醛固酮合成酶活性的异常调节的酶，导致 一种常染色体显性遗传性高血压 糖皮质激素抑制性醛固酮增多症(GSH)。他会尝试 使用适当的临床方法确定患有GSH的家庭成员， 生物化学和分子遗传学标准，并确定 可以在特定类型的突变之间建立关联 以及疾病的临床表现，包括外显性 高血压的表型、高血压的严重程度、激素谱和 出现低钾血症。他将检查一个常客(每个人50% 两个等位基因)可能影响基因调控的遗传多态 细胞色素P11B2。它位于CYP11B2的5‘调控区，领先于 发起人绑定密钥的能力相差4倍 调节蛋白，SF1。怀特博士将确定相应的 这两种形式的启动子的能力存在差异 直接转录适当的报告结构，当它们是 转染小鼠肾上腺Y1细胞或人肾上腺小球 细胞，如果这两个等位基因的基因型与血液相关 一大群正常和/或高血压患者的压力。他 将调查细胞色素P11B2基因和 决定肾素-血管紧张素-醛固酮轴的其他基因 这些人群中的血压。 据推测，11-羟基类固醇脱氢酶缺乏 肾脏远端小管的活动导致常染色体 隐性高血压，称为显性盐皮质激素 太过分了。这种酶在远端小管中的形式似乎是 与之前从肝脏克隆的酶不同，但可能是 与胎盘中表达的同工酶有关。因此，申请人 将分离编码NAD+依赖的人胎盘的cDNA克隆 使用针对纯化蛋白的抗血清形成11-HSD。 同时，他将分离编码11-HSD酶的cDNA克隆(S) 存在于兔远端小管中，在非洲爪哇卵母细胞中表达。他 将表征与这些相对应的人类基因组基因(S) 慢性粒细胞白血病患者的酶活性及此类基因突变的寻找(S) 明显的糖皮质激素过多。如果发现了这样的突变，他会 确定该基因更频繁的多态是否与 正常人群或原发性高血压患者的血压 高血压。

DESCRIPTION: (Adapted from the applicant's abstract): Dr. Perrin White wishes to continue to investigate the role of abnormalities in the genes encoding aldosterone synthase and 11-hydroxysteroid dehydrogenase activities in the development of human hypertension. He has previously demonstrated that recombination between the CYP11B1 (steroid 11- hydroxylase) and CYP11B2 (aldosterone synthase) genes can generate an abnormally-regulated enzyme with aldosterone synthase activity, causing an autosomal dominant form of inherited hypertension termed glucocorticoid-suppressible hyperaldosteronism (GSH). He will attempt to identify family members with GSH using appropriate clinical, biochemical, and molecular genetic criteria and determine whether correlations can be established between the specific type of mutation and the clinical expression of the disease, including penetrance of the hypertensive phenotype, severity of hypertension, hormonal profile, and presence of hypokalemia. He will examine a frequent (50% for each of the two alleles) genetic polymorphism that may affect regulation of CYP11B2. It is located in the 5' regulatory region of CYP11B2, leading to a 4- fold difference in the ability of the promoter to bind a key regulatory protein, SF1. Dr. White will determine if corresponding differences exist in the abilities of the two forms of the promoter to direct transcription of appropriate reporter constructs when they are transfected into mouse Y1 adrenal cells or human adrenal glomerulosa cells, and if genotype for these two alleles is correlated with blood pressure in large groups of normal and/or hypertensive individuals. He will investigate possible correlations between genotype at CYP11B2 and other genes of the renin-angiotensin-aldosterone axis in determining blood pressure in these populations. It is hypothesized that a deficiency in 11-hydroxysteroid dehydrogenase activity in the distal tubule of the kidney leads to an autosomal recessive form of hypertension, termed apparent mineralocorticoid excess. The form of the enzyme in the distal tubule appears to be distinct from the enzyme previously cloned from the liver, but may be related to an isozyme expressed in placenta. Therefore, the applicant will isolate cDNA clones encoding the human placental, NAD+ dependent form of 11-HSD using an antiserum directed against the purified protein. In parallel, he will isolate cDNA clones encoding the 11-HSD enzyme(s) present in rabbit distal tubules by expression in Xenopus oocytes. He will characterize the human genomic gene(s) corresponding to these enzymes and search for mutations in such gene(s) in patients with apparent mineralocorticoid excess. If such mutations are found, he will determine if more frequent polymorphism in the gene correlates with blood pressure in a normal population or among individuals with essential hypertension.