MOLECULAR BIOLOGY OF CELLULAR INJURY

这个研究小组的主要重点是研究对 哺乳动物细胞中的遗传毒性应激。这包括克隆和 各种DNA损伤诱导(DDI)基因的特征。 研究涉及哺乳动物基因，如GADD基因， β-聚合酶、金属硫蛋白和泛素。了解角色 DNA损伤反应在确定细胞对 细胞毒剂。如用于癌症治疗，是一个主要目标： 努力包括在耐药肿瘤细胞中表达DDI基因 (前项目Z01 CM 07187-02 LMPH)。对……的重要回应 所有细胞中的遗传毒性应激都是细胞周期进程的延迟， 都是由DNA损伤引起的。这样的拖延可以起到保护作用。 由于缺乏生长抑制反应的突变体对 某些破坏DNA的毒剂。这些延迟是由不同的基因介导的 可能包括既是DDI又是生长停滞的GADD基因 并在本实验室进行了克隆。主要部分 本课题的重点是：1)这些基因的表达研究 并对这五个基因的cDNA克隆进行了鉴定：2) 这些基因的调控，特别是GADD45；3) GADD蛋白的特性及其研究进展 高亲和力抗体；4)试图阐明这些抗体的功能 使用表达载体和反义方法的基因；5)使用 转基因小鼠模型，研究这些基因在体内的作用。的 特别令人感兴趣的是我们最近的发现，人类的诱导 某些DNA损伤剂介导的GADD45基因是由P53肿瘤介导的 抑制者。在M.Kastan和B.Vogelstein的合作下，我们有 发现这种基因只在含有p53基因的细胞中被x射线诱导。 表型。此外。人类和仓鼠的GADD45基因都含有 一个与P53蛋白强结合的保守的P53共有序列。 这些发现是对一种细胞基因的首次证明 激活依赖于P53。这可能会在以下方面产生重要影响 癌症治疗考虑到大约三分之二的人类肿瘤 缺乏正常(Wt)P53功能。

The major focus of this research group is the study of responses to genotoxic stress in mammalian cells. This has included the cloning and characterization of a variety of DNA-damage-inducible (DDI) genes. Studies have involved mammalian genes such as the gadd genes, beta-polymerase, metallothionein, and ubiquitin. Understanding the role of DNA-damage responses in determining the cellular sensitivity to cytotoxic agents. such as used in cancer therapy, is a major objective: efforts include DDI gene expression in drug-resistant tumor cells (formerly project Z01 CM 07187-02 LMPH). An important response to genotoxic stress in all cells are delays in cell cycle progression which are induced by DNA damage. Such delays can have a protective effect since mutants lacking growth arrest responses are hypersensitive to certain DNA-damaging agents. These delays are mediated by various genes and probably include the gadd genes which are both DDI and growth-arrest inducible and which were cloned in this laboratory. The major portions of this project focus on: 1) the study of the expression of these genes and characterization of the cDNA clones for these five genes: 2) the regulation of these genes with particular emphasis on gadd45; 3) the characterization of the gadd proteins with the development of high-affinity antibodies; 4) attempts to elucidate the function of these genes using expression vectors and antisense approaches; 5) the use of a transgenic mouse models to study the roles of these genes in vivo. Of particular interest is our recent finding that the induction of the human GADD45 gene by certain DNA-damaging agents is mediated by the p53 tumor suppressor. In collaboration with M. Kastan and B. Vogelstein, we have found that this gene is only induced by x rays in cells with a p53 wt phenotype. In addition. both the human and hamster gadd45 genes contain a conserved p53 consensus sequence which strongly binds p53 protein. These findings are the first demonstration of a cellular gene whose activation is dependent on p53. This may have important implications in cancer therapy considering that approximately two thirds of human tumors lack normal(wt) p53 function.