ACETYLTRANSFERASES AND ONCOGENESIS

描述：（逐字改编自研究者摘要）该项目 目的是了解涉及的未知分子事件， 肿瘤发生，特别是翻译后乙酰化的作用， 抑癌基因p53蛋白生长停滞反应的破坏， 已知通过p53基因的错义突变的凋亡途径赋予了一种 选择性的优势，肿瘤克隆，并使他们难治性， 几种抗肿瘤治疗这样的冷漠，至少 部分地，由于大多数p53突变体不能 与p53特异性DNA结合位点结合， 生长调节基因直接基因治疗，通过引入正常的p53 已经尝试过将基因导入肿瘤细胞，但没有得出结论性的结果， 可能是由于几种p53突变体固有的显性负活性 proteins.因此，从p53中拯救正常活性的可能性是不确定的。 p53突变体本身似乎是有吸引力的替代方法。研究显示 p53突变体的DNA结合能力可以通过以下方法在体外重建： 抗p53单克隆抗体加入支持了这一观点， 这是p53结构灵活的重要证据。我现在已经 证明了p53的翻译后乙酰化， 乙酰转移酶P/CAF恢复p53突变体的序列特异性DNA结合 与DNA结合功能障碍的蛋白质。此外，委员会认为， 在携带p53突变的转化细胞系中P/CAF的过表达 基因拯救了大多数转化细胞的表型，包括正常的 形态和对遗传毒性剂的反应性，如紫外线照射。 这些发现暗示P/CAF是细胞内 通常阻止肿瘤发生的通路级联。他们还透露， 存在一种新的分子机制，从而使p53乙酰化，和 MICHT可能与其他调节蛋白共同决定肿瘤的敏感性 细胞转化为治疗剂。我在这里提出遗传学和生物化学的方法 研究P/CAF如何发挥其肿瘤抑制活性。

DESCRIPTION: (adapted verbatim from the investigator's abstract) This project aims to develop an understanding of yet unknown molecular events involved in oncogenesis, specifically the role played by post-translational acetylation of the tumor suppressor p53 protein. Disruption of growth-arrest responses and apoptotic pathways by missense mutations of the p53 gene is known to confer a selective advantage to neoplastic clones and to render them refractory to several anti-neoplastic treatments. Such unresponsiveness is, at least partially, sustained by the fact that most of p53 mutants are incapable of binding to p53-specific DNA-binding sites and thus, of activating growth-regulatory genes. Direct gene therapy, by introduction of a normal p53 gene into tumor cells has been attempted but yielded inconclusive results, probably due to dominant negative activity(s) intrinsic to several p53 mutant proteins. Thus, the possibility of rescuing normal activity(s) from a p53 from a p53 mutant per se appears to attractive alternative approach. Studies showing that the DNA binding ability of p53 mutants can be reestablished in vitro by the addition of anti-p53 monoclonal antibodies, support this view and provide valuable evidence that the structure of p53 is flexible. I have now demonstrated that post-translational acetylation of p53 by the acetyl-transferase, P/CAF, restores sequence specific DNA-binding of p53 mutant proteins otherwise dysfunctional for binding to DNA. Furthermore, overexpression of P/CAF in transformed cell lines carrying mutations of the p53 gene rescues most phenotypes of transformed cells, including a normal morphotype and responsiveness to genotoxic agents, such as UV-irradiation. These findings implicate P/CAF as a crucial component of an intracellular pathway cascade which normally prevents oncogenesis. They also reveal the existence of a novel molecular mechanism whereby acetylation of p53, and perhaps of other regulatory proteins, micht determine the sensitivity of tumor cells to therapeutic agents. I propose here genetic and biochemical approaches to examine how P/CAF exerts its tumor-suppressive activity.