Analysis of Ewing sarcoma using a transgenic mouse

本研究的目的是在尤因肉瘤发生的母体组织中表达癌基因，并分离实验小鼠模型。进一步，确定EWS-FLI融合转录因子控制的靶基因。我们分离了两株携带EWS-FLI癌基因的转基因小鼠。这些小鼠具有生殖潜能，能够在正常条件下繁殖。我们将这些小鼠与神经嵴表达Cre酶的实验小鼠杂交。这使我们能够在体内诱导DNA重组，并在神经嵴源性细胞中激活EWS-FLI致癌基因。由于获得的小鼠数量不够，我们无法判断肉瘤的发生。我们将分离出一种不同的转基因小鼠，并与Cre转基因小鼠再次杂交。在我们引入致癌基因EWS-FLI的细胞系中，我们发现该基因的表达发生了显著改变。通过cDNA阵列分析，我们发现EWS-FLI激活了细胞外基质成分tenascin基因。我们还发现一个融合转录因子激活了与细胞永生相关的端粒酶基因。我们将继续制作Ewing肉瘤模型实验小鼠，并将研究靶基因在肿瘤发展中的作用。

A goal of this study is to express the oncogene in mother tissue for Ewing sarcoma-genesis and to isolate a model laboratory mouse. Furthermore, it is to identify a target gene which the EWS-FLI fusion transcription factor controls. We isolated a transgenic mouse of two strains carrying EWS-FLI oncogene. These mice had reproductive potential and were able to propagate in a normal condition. We crossbred these mice with the laboratory mouse which expresses Cre enzyme in neural crest. This allows us to induce a recombination of DNA in vivo and an activation of EWS-FLI oncogene in neural crest-derived cells. Since mouse was not obtained in enough numbers, we were unable to judge sarcoma-genesis. We are going to isolate a different strain of transgenic mouse and crossbreed it with the Cre transgenic mouse again. In the cell line which we introduced the oncogene EWS-FLI into, we found the gene which expression was significantly altered. We made clear by cDNA array method that the tenascin gene, an extra-cellular matrix component, was activated by EWS-FLI. Also we found that a fusion transcription factor activated telomerase gene which is associated with cellular immortalization. We continue manufacture of model laboratory mouse of Ewing sarcoma and are going to examine a role of target gene in development of the neoplasm.