Lung specific expression of a human mutant p53 affects cell proliferation in transgenic mice
Lung specific expression of a human mutant p53 affects cell proliferation in transgenic mice
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DOI：
10.1007/s11248-007-9154-3
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发表时间：
2008-06-01
影响因子：
3
通讯作者：
Villalona-Calero, Miguel A.
中科院分区：
文献类型：
--
作者：
Duan, Wenrui;Gao, Li;Villalona-Calero, Miguel A.
人突变型p53（273 H）在体外已显示出具有显性负性和功能获得性，以及保留部分DNA结合和转录激活功能.我们已经开发了一种转基因小鼠品系，其中人突变型p53（273 H）以肺特异性方式表达（p53（+/+/TG））。将转基因小鼠与p53敲除小鼠杂交，产生了具有各种遗传背景的小鼠。为探讨p53突变体对小鼠肺组织细胞增殖的影响，采用溴脱氧尿苷（BrdU）标记法和增殖细胞核抗原（PCNA）表达法检测了p53突变体对小鼠肺组织细胞增殖的影响。BrdU分析显示，与（p53（-/+））小鼠相比，（p53（-/+/TG））小鼠中BrdU阳性细胞的数量增加了3.7倍，而与p53（-/-）肺相比，在p53（-/-/TG）肺中没有观察到增殖率的差异。经γ射线照射后，p53（-/+/TG）和p53（-/+）小鼠肺中均无BrdU阳性细胞，而p53（-/-/TG）小鼠肺中的细胞增殖率较p53（-/-）小鼠肺中的细胞增殖率降低。真实的时间PCR结果表明，p53（273 H）突变体在转基因小鼠中不保留激活p21（WAF 1/CIP 1）表达的功能。上述结果表明，体内人突变型p53（273 H）的过表达导致基础增殖速率的增加，这需要野生型p53的存在。突变型p53（273 H）可能通过干扰鼠内源性p53功能影响细胞增殖。
The human mutant p53(273H) has been shown in vitro to have both dominant- negative and gain- of- function properties, as well as to retain partial DNA- binding and transcriptional activation functions. We have developed a line of transgenic mice in which the human mutant p53(273H) is expressed in a lung specific manner (p53(+/+/TG)). Crossing of the transgenic mice with p53 knockout mice led to generate mice with various genetic backgrounds. To evaluate the influence of p53 mutants in cell proliferation in mice lung tissue, we analyzed cell proliferation rate by Bromodeoxyuridine (BrdU) labeling and by expression of proliferating cell nuclear antigen (PCNA). BrdU analysis showed a 3.7- fold increase in the number of BrdU positive cells in the (p53(-/+/TG)) mice compared to the (p53(-/+)) mice, whereas no difference was observed in proliferation rate in the p53(-/-/TG) lungs as compared to p53(-/-) lungs. After the mice were treated with gamma-irradiation, BrdU positive cells were absent from both the p53(-/+/TG) and p53(-/+) mice, whereas a decrease in the rate of cell proliferation occurred in p53(-/-/TG) lungs as compared to p53(-/-) lungs. Real time PCR results indicated that the p53(273H) mutant did not retain the function to activate expression of p21(WAF1/CIP1) in the transgenic mice. The above results indicate that overexpression of the human mutant p53(273H) in vivo results in an increase in basal proliferation rate which requires the presence of wild type p53. Mutant p53(273H) may affect cell proliferation by interrupting murine endogenous p53 function.