TRANSFORMING DOMAINS IN THE IGF-1 RECEPTOR

我们已经从小鼠胚胎中获得了细胞系， 破坏胰岛素样生长因子1型受体（IGF-1 R） 基因（Lui et al.1993，Baker et al.1993）。这些IGF-1的细胞系 R基因敲除小鼠和来自野生型同窝小鼠（分别为R-和W） 不同的是它们的生长和相对容易的转化。R细胞， 与W细胞不同，在无血清培养基中不进行细胞分裂 补充有PDGF、EGF、IGF-1，并且不能被 引入猿猴病毒40（SV 4 O）大T抗原。R细胞 表达SV 40 T抗原（（tsA）R-）的细胞保留了 含血清培养基中的正常成纤维细胞。野外放归 型IGF-1 R进入tsAR-细胞恢复转化能力， SV 40 T抗原。初步数据显示， 由IGF-1 R在细胞内产生的信号，其特异于 DNA合成或增殖（即进入有丝分裂），这些 信号可以与细胞转化所需的信号分开。一 截短的IGF-1 R允许R细胞响应IGF-1而增殖， 不允许在（tsA）R-细胞中转化。为了扩大这些 结果，并检查发散的细胞信号的水平， IGF-1 R我们建议在受体中引入特定突变， 在R-和（tsA）R-细胞中表达这些突变受体。的能力 这些突变受体诱导进入S期，有丝分裂和各种 转化方面;即病灶形成，锚定独立 将测定生长和致瘤性。

We have derived cell lines from mouse embryos homozygous for a targeted disruption of the insulin like growth factor type 1 receptor (IGF-1 R) gene (Lui et al. 1993, Baker et al. 1993). The cell lines from these IGF-1 R knockout mice and from wild type littermates (R- and W respectively) differ in their growth and relative ease of transformation. The R- cells, unlike W cells, do not undergo cell division in serum free medium supplemented with PDGF, EGF, IGF-1, and cannot be transformed by the introduction of the simian virus 40 (SV4O) large T antigen. The R- cells expressing the SV4O T antigen ((tsA)R-) retain the characteristics of normal fibroblasts in serum containing medium. Reintroduction of the wild type IGF-1 R into the tsAR- cells restores the transforming capacity of the SV4O T antigen. Preliminary data indicates that there are distinct signals generated by the IGF-1 R within the cell which are specific for DNA synthesis or proliferation (i.e. entry into mitosis) and that these signals may be separate from those needed for cellular transformation. A truncated IGF-1 R allows R-cells to proliferate in response to IGF-1 but does not allow transformation in (tsA)R- cells. In order to extend these results and to examine divergence of cellular signals at the level of the IGF-1 R we propose to introduce specific mutations in the receptor and to express these mutant receptors in R- and (tsA)R- cells. The ability of these mutant receptors to induce entry into S phase, mitosis and various aspects of transformation; i.e. foci formation, anchorage independent growth, and tumorigenicity, will be determined.