THE MOLECULAR MECHANISMS OF ONCOGENE ACTION

分子生物学在上皮细胞研究中的应用进展 癌症导致了对特定基因损伤的识别 导致关键靶基因的激活或失活。这些 被称为癌基因的基因涉及细胞生长的各个方面。 调节，因此在早期致癌过程中起主要作用 “启蒙”与“提升”之分。现在至关重要的是要理解 这些基因发挥作用的精确机制如此分子或 最终可以衍生出药理药物来改变或抑制它们的 效果。 本项目的目的是阐明生物化学和分子生物学。 癌基因转化哺乳动物细胞的机制。为此，我们 对MyC、Jun和MyC成员进行了结构/功能分析 FOS癌基因家族。这些研究揭示了各种结构 这些蛋白质的哪些方面是必要的和充分的 转型。 我们对c-jun癌基因的研究表明，除了DNA 结合和二聚结构域，N-末端反式激活结构域是 是细胞转化所必需的。此外，c-jun的能力 反式激活与其转化细胞的能力相关。因此，c-jun 似乎通过调节基因表达来改变细胞。此外， 详细的c-jun突变分析表明，磷酸化 丝氨酸63/73的cJun导致反式激活增加和 最终转变。这些位点的磷酸化发生在 部分通过ras/RAF依赖的途径提供了一个重要的 这些癌基因之间的生化联系。最近的研究旨在 更详细地分析其他c-jun后翻译标语和 它们的生化和生物学效应及其与c-fos的平行研究 癌基因研究磷酸化与生物学的关系 活动。 我们对myc癌基因的研究主要集中在比较 C-myc和L-myc基因的反式激活和转化活性。 通过外显子改组，我们已经证明了L-myc反式激活和 转换效率比c-myc低得多，这种差异是局部的 到第二个外显子。最近的工作集中在精确的结构上。 这些基因之间的差异及其在细胞凋亡中的作用。

Recent developments in the application of molecular biology to epithelial cancers have led to the identification of specific genetic lesions resulting in either activation or inactivation of key target genes. These genes, called oncogenes, are involved in various aspects of cell growth regulation and as such play major roles in the early carcinogenic processes of "initiation" and "promotion." It is now critical to understand the precise mechanisms by which these genes function so molecular or pharmacologic agents can ultimately be derived to alter or repress their effects. The purpose of this project is to elucidate the biochemical and molecular mechanisms by which oncogenes transform mammalian cells. To this end, we have performed structure/function analysis on members of the myc, jun and fos oncogene families. These studies have revealed various structural aspects of these proteins which are necessary and sufficient for transformation. Our studies of the c-jun oncogene revealed that in addition to the DNA binding and dimerization domains, the N-terminal transactivation domain is required for cellular transformation. In addition, the ability of c-jun to transactivate correlates with its ability to transform cells. Thus, c-jun appears to transform cells by regulating gene expression. Further, detailed mutation analysis of c-jun has demonstrated that phosphorylation of cJun at serines 63/73 results in increased transactivation and ultimately transformation. The phosphorylation of these sites occurs in part through a ras/raf dependent pathway which provides an important biochemical link between these oncogenes. More recent studies are aimed at a more detailed analysis on other c-jun post-translational modications and their biochemical and biologic effects and parallel studies with the c-fos oncogene examining the relationship between phosphorylation and biologic activity. Our studies of the myc oncogene have focused on comparing the transactivating and transforming activities of the c-myc and L-myc genes. By exon shuffking, we have demonstrated that L-myc transactivates and transforms much less ef~ciently than c-myc and this difference is localized to the second exon. More recent work has focused on the precise structural differences between these genes and their role in apotosis.