ONCOGENES, ONCOGENE PRODUCTS IN RADIATION-INDUCED TUMORS

这个项目的目标是评估癌基因的假设 这种表达是辐射致癌过程中的一个步骤。这种可能性 正在使用一种大鼠甲状腺癌变模型进行评估 甲状腺上皮对致癌作用的敏感度 电离辐射。发现的显性转化癌基因 来自辐射诱导的腺瘤和癌症的细胞基因组正在 与从正常甲状腺组织DNA中分离的DNA序列进行比较 细胞和自发性甲状腺肿瘤的细胞。同样，mRNAs 与所提到的癌基因有关的转录本和蛋白质产物 以上都在分析中。它们的结构和功能 大分子将与那些与已知分子相关的大分子进行比较 逆转录病毒致癌基因。 放射性甲状腺肿瘤和自发性甲状腺肿瘤的细胞DNA 以及来自正常甲状腺细胞的细胞受到限制 利用全长基因进行内切酶酶切和Southern印迹分析 一组尼克翻译的逆转录病毒癌基因探针。 使用从辐射诱导的甲状腺癌中提取的DNA，我们已经 能够识别RASK、MyC和ABL中的突变和DNA重排 致癌基因。该DNA也能在体内转染NIH/3T3细胞。 DNA介导的基因转移实验。目前，分子克隆和 测序技术被用来定位显性转化 致癌基因。一旦受影响的癌基因被分离出来，它们的个体和 协同效应将在转基因试验中测试，使用 重组DNA分子携带这些癌基因的c DNA拷贝 真核表达载体。 Northern杂交分析正在被用来确定 这3种癌基因在正常组织和肿瘤组织中的表达。的cDNA拷贝 受影响的癌基因正被克隆到细菌质粒中，并 癌基因特异性蛋白正在使用特定的抗血清进行表征 反对Myc和RaskProtein产品。这些蛋白质是 在定位、相对分子质量、 蛋白激酶活性、GTP酶活性和GTP结合活性。这些参数 将与已知的逆转录病毒转化蛋白进行比较。

The goal of this project is to evaluate the hypothesis that oncogene expression occurs as a step in radiation carcinogenesis. This possibility is being evaluated using a rat thyroid carcinogenesis model capitolizing on the exquisite sensitivity of thyroid epithelium to the carcinogenic effects of ionizing radiation. Dominant transforming oncogenes identified in the genome of cells from radiation-induced adenomas and carcinomas are being characterized and compared to those isolated from the DNA of normal thyroid cells and cells from spontaneous thyroid tumors. Likewise, the mRNA transcripts and protein products associated with the oncogenes mentioned above are being analyzed. The structure and function of these macromolecules will be compared with those associated with the known retroviral oncogenes. The cellular DNA from radiation-induced and spontaneous thyroid tumors as well as from normal thyroid cells are being subjected to restriction endonuclease digestion and Southern blot analysis utilizing a complete battery of nick translated retroviral oncogene probes. Using DNA isolated from a radiation-induced thyroid carcinoma we have been able to identify mutations and DNA rearrangements in the rask, myc, and abl oncogenes. This DNA is also capable of transfecting NIH/3T3 cells in the DNA mediated gene transfer assays. At present molecular cloning and sequencing techniques are being used to localize the dominant transforming oncogene. Once the effected oncogenes are isolated their individual and collaborative effects will be tested in the transfection assays using recombinant DNA molecules harboring cDNA copies of these oncogenes in eukaryotic expression vectors. Northern blot analysis is being utilized to determine the level of expression of these 3 oncogenes in normal and tumor tissue. cDNA copies of the affected oncogenes are being cloned in bacterial plasmids and oncogene-specific proteins are being characterized using specific antisera against myc and rask protein products. These proteins are being characterized with respect to localization, molecular weight, protein-kinase activity, GTPase and GTP-binding activity. These parameters will be compared with those of known retroviral transforming proteins.