分析myc小鼠的转基因复本和肿瘤发生

Analysis of transgene copies and tumor development in mice bearing myc genes

目的 :研究带外源myc和ras转基因小鼠的致瘤潜能和肿瘤生物学特性。方法 :斑点杂交、光密度测量和Southrn印迹分析myc小鼠基因组和诱发的肿瘤DNA。肿瘤组织经过显微镜观察和免疫组织化学反应。结果 :在存活一年以上的 3 8只转基因小鼠中有 12只 ( 9myc和 3myc+ras)发生多种肿瘤 ,其组织类型以成淋巴细胞瘤和纤维肉瘤居多。肿瘤组织含有的myc癌蛋白显著高于四周正常组织 ,2 4例myc小鼠基因组DNA含myc基因为三倍体。在 3例myc小鼠肿瘤TDNA中 ,1例为二倍体 ,2例为超四倍体。结论

Objective:To investigate the tumorigenic potential and biological character of tumors in transgenic mice bearing exogenous myc and ras genes. Method:Dot hybridization,photometric determination and Southern blot were used to analyze the genomic DNA of transgenic mice and induced tumors.Microscopic observation and immunohistochemical reaction were performed to study the tumor tissues. Results:Among 38 transgenic mice surviving beyond one year.12(9 myc and 3 myc+ras)mice developed multiple neoplasms.Most tumors were observed as lymphoblastoma and fibrosarcoma in histological types.The Myc oncoprotein in tumor tissue was significantly higher than that in surrounding normal tissue.The myc gene copies in the genome of 24 transgenic mice reached to triploid(3 16N).As for the copies of myc gene in tumor DNA,one sample maintains diploid(1 95N),two samples amplified up to hyper tetraploid(4 21N). Conclusion:The amplification of myc genes and overexpression of Myc oncoprotein may play important role in the tumorigenesis in transgenic mice.