关键词: Trp53基因, 基因剔除, 肿瘤发生, 药物致癌性评价

Abstract: Objective To establish Trp53 gene knockout mouse. Methods Using ET cloning, homologous recombination, microinjection technology, the Trp53 gene knockout mouse with the deletion of exons 2 to 11 was established. PCR, RT-PCR and Western blot were used to detect the expression of Trp53 in Trp53^+/+, Trp53^+/- and Trp53^-/- mice. The phenotype of the knockout mice was analyzed by spontaneous tumors observation and histopathological examination. The susceptibility of Trp53 heterozygote (+/-) and wild type (+/+) mice to N-methyl-N-nitrosourea (MNU) was investigated to assess the application of the knockout mouse in carcinogenicity assessment of pharmaceuticals. Results PCR, RT-PCR and Western blot confirmed the deletion of Trp53 gene in the knockout mouse. Trp53^-/- mice appear normal but are highly susceptible to genesis of a variety of tumors at a very early age-13 weeks of age and all have developed tumor and died by 36 weeks of age. These mice developed many deferent types of tumors, but the most frequently observed tumor is malignant lymphoma, occurring in more than 60% of the mice. Mortality from N-methyl-N-nitrosourea (MNU)-induced lymphomas was much greeter in Trp53^+/- group. After a single intraperitoneal injection of MNU at dose of 75mg/kg in twenty male and female Trp53^+/- and Trp53^+/+ mice, eighteen male Trp53^+/-mice or female mice developed tumors, especially the malignant lymphoma of thymus, Trp53^+/- in mice 86%. Twenty Trp53^+/- mice and Trp53^+/+mice per sex receiving a single intraperitoneal injection of citrate buffer appeared normal and no tumor was found. Conclusion The Trp53 gene knockout mice have been established , which can be use in the function study of Trp53 gene and the carcinogenicity assessment of pharmaceuticals.

Key words: Trp53 gene, Gene knockout, Tumorigenesis, Drug carcinogenicity assessment