MECHANISM OF ONCOGENE ACTIVATION IN MOUSE LYMPHOMAS

在本申请中，我们将继续研究转化基因 与γ射线诱发的C57 BL/6 J胸腺淋巴瘤相关 小鼠我们已经报道了一个特定的标记染色体， 12例中有5例发生1 ~ 5号染色体易位 γ射线诱发胸腺淋巴瘤。这5个胸腺细胞的DNA 淋巴瘤含有一种新的非ras转化活性， 应用敏感的裸鼠致瘤性试验进行DNA介导的基因转移 小鼠对转化DNA序列的存在进行评分。我们将克隆 新的转化基因，使用裸鼠致瘤性测定 以监测克隆的DNA片段的生物活性。详细 将构建癌基因的限制性内切酶图谱。一 生物活性DNA片段的亚克隆，由单个 拷贝小鼠DNA，将用于Southern和北方印迹分析， 确定小鼠基因组中基因的数量和排列， 基因是否以mRNA表达。为了确定 5例原发性放射性胸腺淋巴瘤的癌基因激活 含有标记染色体、五个致癌基因或相关部分的 将被克隆。如果这5个基因是 同样，精细的详细分析将确定染色体的性质。 导致致癌基因激活的变化。如果这5个基因不同， 然后克隆和DNA序列分析将确定 致癌基因激活的机制。最后，我们将评估 小鼠胸腺细胞中癌基因的激活 辐照处理如果激活的癌基因与 标记染色体的存在，然后聚合酶链反应（PCR） 技术将用于检测染色体断裂点 在疾病的不同阶段。实验动物模型 在深入了解一些步骤方面非常有用， 参与疾病进展。这项研究应该阐明一些 与癌基因激活有关的机制，因为它们与 染色体片段的易位，并有可能 鉴定涉及淋巴恶性肿瘤的新癌基因。

In this application we will continue to study the transforming genes associated with gamma irradiation induced thymic lymphomas in C57BL/6J mice. We have reported a specific marker chromosome consisting of a translocation between chromosomes one and five was observed in 5 of 12 gamma irradiation induced thymic lymphomas. DNA from these 5 thymic lymphomas contains a novel non-ras transforming activity detected by DNA-mediated-gene-transfer using a sensitive tumorigenicity assay in nude mice to score for the presence of transforming DNA sequences. We will clone the novel transforming gene(s), using the nude mouse tumorigenicity assay to monitor the biological activity of the cloned DNA fragments. A detailed restriction endonuclease map of the oncogene(s) will be constructed. A subclone of the biologicallly active DNA fragment, consisting of single copy mouse DNA, will be used in Southern and Northern blot analysis to determine the number and arrangement of the gene(s) in the mouse genome and whether the gene(s) is expressed in mRNA. To determine the mechanism of oncogene activation in the 5 primary radiation-induced thymic lymphomas containing the marker chromosome, the five oncogenes, or relevant portions of the transforming DNA sequences, will be cloned. If the 5 genes are the same, fine detail analysis will determine the nature of the chromosomal change(s) resulting in oncogene activation. If the 5 genes are different, then cloning and DNA sequence analysis will determine the different mechanisms of oncogene activation. Finally, we will assess the timing of oncogene activation in mouse thymocytes at intervals following gamma irradiation treatment. If the activated oncogene is associated with the presence of the marker chromosome, then the polymerase chain reaction (PCR) technique will be used to detect the breakpoint of the chromosome translocation at different stages of disease. Experimental animal models have been extremely useful in gaining insights into some of the steps involved in disease progression. This study should elucidate some of the mechanisms involved in oncogene activation as they are related to the translocation of chromosomal segments, and has the potential for identifying a new oncogene(s) involved in lymphoid malignancies.