WRN helicase expression in Werner syndrome cell lines
WRN helicase expression in Werner syndrome cell lines
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DOI：
10.1093/nar/28.2.648
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发表时间：
2000-01-15
影响因子：
14.9
通讯作者：
Monnat, RJ
中科院分区：
文献类型：
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作者：
Moser, MJ;Kamath-Loeb, AS;Monnat, RJ
染色体8p WRN基因的突变会导致Werner综合征(WRN)，这是一种人类常染色体隐性遗传病，模仿早衰，与遗传不稳定和癌症风险增加有关。在WRN患者中发现的所有WRN突变都被预测为截断WRN蛋白，并失去C-末端的核定位信号，然而，许多被截断的蛋白质将保留WRN解旋酶和/或核酸酶功能区。我们结合免疫印迹和免疫沉淀试验对WRN蛋白及其相关的3‘-->进行了定量；在具有基因特征的WRN患者细胞系中，5‘解旋酶活性，来自四个不同WRN突变的患者的细胞系中没有一个包含可检测到的WRN蛋白或免疫可沉淀的WRN解旋酶活性，来自WRN杂合子个体的细胞系包含较少的WRN蛋白和解旋酶活性，定量免疫印迹分析表明，淋巴母细胞系和成纤维细胞都含有类似于6 x 10(4)WRN分子/细胞的WRN分子，我们的结果表明，大多数WRN突变导致功能相同的零等位基因，WRN杂合子效应可能是单倍体不足造成的，在小鼠或其他模型系统中成功建立WRN发病机制模型将需要使用消除WRN蛋白表达的WRN突变。
Mutations in the chromosome 8p WRN gene cause Werner syndrome (WRN), a human autosomal recessive disease that mimics premature aging and is associated with genetic instability and an increased risk of cancer. All of the WRN mutations identified in WRN patients are predicted to truncate the WRN protein with loss of a C-terminal nuclear localization signal, However, many of these truncated proteins would retain WRN helicase and/or nuclease functional domains, We have used a combination of immune blot and immune precipitation assays to quantify WRN protein and its associated 3'-->5' helicase activity in genetically characterized WRN patient cell lines, None of the cell lines from patients harboring four different WRN mutations contained detectable WRN protein or immune-precipitable WRN helicase activity, Cell lines from WRN heterozygous individuals contained reduced amounts of both WRN protein and helicase activity, Quantitative immune blot analyses indicate that both lymphoblastoid cell lines and fibroblasts contain similar to 6 x 10(4) WRN molecules/cell, Our results indicate that most WRN mutations result in functionally equivalent null alleles, that WRN heterozygote effects may result from haploinsufficiency and that successful modeling of WRN pathogenesis in the mouse or in other model systems will require the use of WRN mutations that eliminate WRN protein expression.