TRANSFORMING POTENTIAL OF CELLULAR ONCOGENES

这些实验的目的是评估细胞的能力 癌基因(c-onc)在体内转化细胞。转型潜力 C-fos和c-mos这两个小鼠c-onc基因。一批 含有这些c-onc基因的DNA构建体结合显性 可选择的标记基因、可诱导启动子和/或LTR增强子区域 都会被制造出来。这些结构将被转移到小鼠胚胎来源的 使用DNA转基因程序的畸胎癌细胞(EK细胞)。克隆性 从单个转基因细胞衍生的细胞系将被鉴定为 确定c-onc基因插入的数量、整合的数量 和c-onc转录活性。转基因的EK细胞将被 引入两个体内测试系统来评估转化 C-fos和c-mos的潜能。在第一个系统中，转基因的EK细胞 将被注射到小鼠的囊胚中，以产生嵌合体小鼠。这个 这些小鼠体内肿瘤的形成和c-onc转录活性 被评估。在第二个系统中，转基因的EK细胞或嵌合体 胚胎(注射了转基因EK细胞的囊胚)将被 移植到成年小鼠体内的异位部位，并由此产生 畸胎样肿瘤将被定性。这些措施的具体目标是 实验将确定：(1)c-onc转录增加是否 足以在小鼠体内诱导肿瘤形成和/或改变 因以下原因而形成的畸胎癌和畸胎瘤的发生率 成人异位移植胚胎或畸胎癌细胞 宿主，或(2)是否需要c-onc基因的改变来激活 它在体内的转化潜力。此外，这些测试的结果 实验将阐明一些因素的影响，包括 遗传背景、组织特异性和整合位点(S)，关于 C-onc基因的转化潜能。对这一概念的理解 这些细胞基因的转化潜力将直接影响到 采用在治疗中使用的策略，并最终在 预防人类癌症。(十)

The purpose of these experiments is to assess the ability of cellular oncogenes (c-onc) to transform cells in vivo. The transforming potential of two mouse c-onc genes, c-fos and c-mos, will be examined. A number of DNA constructs containing these c-onc genes in combination with dominant selectable marker genes, inducible promoters, and/or LTR enhancer regions will be made. These constructs will be transferred to mouse embryo-derived teratocarcinoma cells (EK cells) using DNA transfection procedures. Clonal lines derived from single transfected cells will be characterized to determine the number of inserted c-onc genes, the number of integration sites, and c-onc transcriptional activity. Transfected EK cells will be introduced into two in vivo test systems to assess the transforming potential of c-fos and c-mos. In the first system, transfected EK cells will be injected into mouse blastocysts to produce chimeric mice. The formation of tumors and c-onc transcriptional activity in these mice will be assessed. In the second system, transfected EK cells or chimeric embryos (blastocysts injected with transfected EK cells) will be transplanted to ectopic sites in adult mouse hosts and the resulting teratoid tumors will be characterized. The specific aims of these experiments are to determine whether: (1)\increased c-onc transcription is sufficient to induce tumor formation in a mouse and/or to alter the incidence of teratocarcinomas and teratomas formed as a result of transplanting embryos or teratocarcinoma cells to ectopic sites in adult hosts, or (2)\whether alterations in a c-onc gene are necessary to activate its transforming potential in vivo. Additionally, the results of these experiments will elucidate the effects of a number of factors, including genetic background, tissue specificity, and integration site(s), on the transforming potential of c-onc genes. An understanding of the transforming potential of these cellular genes will directly influence the adoption of strategies used in the treatment and, ultimately, in the prevention of human cancer. (X)