ACTIVATING MUTATIONS IN P53 PRODUCE A COMMON CONFORMATIONAL EFFECT - A MONOCLONAL-ANTIBODY SPECIFIC FOR THE MUTANT FORM
ACTIVATING MUTATIONS IN P53 PRODUCE A COMMON CONFORMATIONAL EFFECT - A MONOCLONAL-ANTIBODY SPECIFIC FOR THE MUTANT FORM
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DOI：
10.1002/j.1460-2075.1990.tb08279.x
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发表时间：
1990-05-01
期刊：
影响因子：
11.4
通讯作者：
LANE, DP
中科院分区：
文献类型：
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作者：
GANNON, JV;GREAVES, R;LANE, DP
p53基因的点突变是人类癌症中最常见的遗传变化。它们将小鼠p53从肿瘤抑制基因转化为显性转化癌基因，能够使原代细胞永生，并与激活的ras基因结合实现完全转化。在人类和小鼠系统中，突变都位于p53的区域，从人类到非洲爪蟾都是保守的。我们已经开发了一种针对p53的单克隆抗体，命名为PAb240，它不会免疫沉淀野生型p53。一系列不同的p53突变体与PAb240的反应都比与PAb246的反应更强烈。p53的PAb240反应型不能与SV40大T抗原结合，但可以与HSP70结合。相反，PAb246形式与T抗原结合，但不与HSP70结合。PAb240可以识别所有变性的p53。它在免疫印迹中与所有哺乳动物p53和鸡p53发生反应。我们提出，PAb240对p53的免疫沉淀可以诊断小鼠和人类系统中的突变，并表明将p53从隐性癌基因转化为显性癌基因的不同点突变对该蛋白产生了共同的构象影响。这种构象变化消除T抗原结合并促进自寡聚化。这些结果与显性阴性模型一致，即突变型p53蛋白结合并中和野生型构象中的p53活性。
Point mutations in the p53 gene are the most frequently identified genetic change in human cancer. They convert murine p53 from a tumor suppressor gene into a dominant transforming oncogene able to immortalize primary cells and bring about full transformation in combination with an activated ras gene. In both the human and murine systems the mutations lie in regions of p53 conserved from man to Xenopus. We have developed a monoclonal antibody to p53 designated PAb240 which does not immunoprecipitate wild type p53. A series of different p53 mutants all react more strongly with PAb240 than with PAb246. The PAb240 reactive form of p53 cannot bind to SV40 large T antigen but does bind to HSP70. In contrast, the PAb246 form binds to T antigen but not to HSP70. PAb240 recognizes all forms of p53 when they are denatured. It reacts with all mammalian p53 and chicken p53 in immunoblots. We propose that immunoprecipitation of p53 by PAb240 is diagnostic of mutations in both murine and human systems and suggest that the different point mutations which convert p53 from a recessive to a dominant oncogene exert a common conformational effect on the protein. This conformational change abolishes T antigen binding and promotes self-oligomerization. These results are consistent with a dominant negative model where mutant p53 protein binds to and neutralizes the activity of p53 in the wild type conformation.