THE MOLECULAR MECHANISMS OF ONCOGENE ACTION

分子生物学在上皮细胞中的应用进展 癌症导致了特定遗传病变的鉴定， 关键靶基因的激活或失活。 这些基因， 称为癌基因，涉及细胞调节的各个方面。 在早期致癌过程中起主要作用 “启蒙”和“提升”的区别。“现在至关重要的是要了解 这些基因发挥作用的精确机制，所以分子或 可以衍生药理学试剂以改变或抑制它们的作用。 这个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。 本 最后，我们进行了结构/功能分析， jun癌基因家族 这项研究揭示了各种结构方面 这些蛋白质是转化所必需的 和转录调控。 我们对c-jun癌基因的研究表明，除了DNA 结合和二聚化结构域，N-末端反式激活结构域 是细胞转化所必需的 此外，c-jun的能力 似乎通过调节基因表达来转化细胞。 此外，本发明还 详细的c-jun突变分析表明磷酸化 在丝氨酸63/73处的c-Jun导致反式激活增加， 最终转型。 这些位点的磷酸化部分是 通过ras/raf依赖性途径， 这些致癌基因之间的生物化学联系。 最近的研究表明 c-jun通过改变细胞周期的特定部分来转化细胞 c-jun实现这一点的机制现在正在被 探讨了 我们在6月B进行了类似的研究。 Jun B是c- jun诱导反式激活。 使用一系列缺失突变体，我们得到 绘制了这种抑制作用的关键区域，包括 亮氨酸拉链、DNA结合结构域和反式阻遏结构域， DNA结合结构域的5'端。 未来的研究旨在确定 这些突变体的生物学功能， 反式阻遏结构域和协同蛋白所需的 Jun B抑制活性。

Recent development in the application of molecular biology to epithelial cancers has 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 in the regulation of cell growth and as such play major roles in the early carcinogenic processes of "initiation" and "promotion." It is now critical to understand the precise mechanism by which these genes function, so molecular or pharmacologic agents can 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 jun oncogene family. This study has revealed various structural aspects of these proteins which are necessary and sufficient for transformation and transcriptional regulation. 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 appears to transform cells by regulating gene expression. Further, detailed mutation analysis of c-jun has demonstrated that phosphorylation of c-Jun at serines 63/73 results in increased transactivation and ultimately transformation. The phosphorylation of these sites is in part through a ras/raf dependent pathway which provides an important biochemical link between these oncogenes. More recent studies suggest that c-jun transforms cells by altering specific portions of the cell cycle The mechanisms by which c-jun accomplishes this are now being explored. We have performed similar studies on Jun B. Jun B is an inhibitor of c- jun induced transactivation. Using a series of deletion mutants, we have mapped the regions critical for this inhibitory action to include the leucine zipper, DNA binding domain and a transrepression domain just 5' of the DNA binding domain. Future studies are aimed at defining the biologic functions of these mutants, the molecular action of the transrepression domain and the collaborating proteins required for the inhibitory activity of Jun B.