A TEMPERATURE-SENSITIVE MUTANT OF HUMAN P53
A TEMPERATURE-SENSITIVE MUTANT OF HUMAN P53
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DOI：
10.1002/j.1460-2075.1994.tb06543.x
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发表时间：
1994-06-01
期刊：
影响因子：
11.4
通讯作者：
DEISSEROTH, AB
中科院分区：
文献类型：
--
作者：
ZHANG, W;GUO, XY;DEISSEROTH, AB
我们发现，人类“热点”p53突变体143Ala对两个DNA元件的结合和介导下游荧光素酶报告基因的转录具有温度敏感性。在32.5℃时，143Ala具有很强的DNA结合能力。此外，其转录活性比野生型p53强。然而，在37.5摄氏度时，突变体的DNA结合和转录激活功能都大大减少或取消。活性差异与p53的两种构象状态的存在相关，这两种构象状态可以被单克隆抗体识别：在32.5℃时，143Ala被PAb1620识别，这是野生型构象的特异性，而在37.5℃时，143Ala几乎无法被PAb1620介导的免疫沉淀检测到。尽管在32.5℃时，143Ala与p53 DNA识别元件的结合以及对报告基因转录的激活明显高于野生型p53，但143Ala对增殖的抑制不如野生型p53强烈，也没有增加对ras诱导的病灶形成的抑制。这些结果表明，参与转录激活的事件与参与p53增殖抑制的事件之间存在部分相关性。因此，ala将用于解剖p53的结构与其不同细胞功能之间的关系。
We discovered that the human 'hot-spot' p53 mutant 143Ala is temperature sensitive for the binding of two DNA elements and for mediating the transcription of a downstream luciferase reporter gene. At 32.5 degrees C, 143Ala possesses strong DNA binding ability. In addition, its transcriptional activities are stronger than those of wildtype p53. At 37.5 degrees C, however, both the mutant's DNA binding and transcriptional activation functions are greatly reduced or abolished. The activity differences correlate with the presence of two conformational states of p53, which are recognized by monoclonal antibodies: at 32.5 degrees C, 143Ala is recognized by PAb1620, which is specific for the wild-type conformation, whereas at 37.5 degrees C, 143Ala is almost undetectable by PAb1620-mediated immunoprecipitation. Although 143Ala's binding to p53 DNA recognition elements and its activation of reporter gene transcription at 32.5 degrees C is markedly higher than that of the wild-type p53, 143Ala inhibited proliferation less robustly than wild-type p53 and it did not increase inhibition of ras-induced focus formation. These results indicate a partial correlation between the events involved in transcriptional activation and events involved in the proliferation suppression of p53. 143Ala therefore will be of use in dissecting the relationship between the structure of p53 and its different cellular functions.