Cellular Responses to DNA Damage

我们正在努力建立一个体外系统，用于研究人类细胞中DNA损伤反应系统对检查点激活的作用。作为一个模型系统，我们正在研究由DNA错配修复蛋白MutSalpha和MutLalpha介导的检查点激活对几种DNA损伤剂（包括SN1烷基化剂、氟尿嘧啶和顺铂）的反应。针对特定类型DNA损伤的DNA损伤传感器激活ATR和ATM蛋白激酶。这进而激活包括Chk1和Chk2在内的一系列信号激酶，最终导致细胞周期在G2/M边界阻滞。我们正在纯化参与这种损伤反应的重组人蛋白，目的是确定潜在的分子机制。

We are working to establish an in vitro system for the study of checkpoint activation by the DNA damage response systems operating in human cells. As a model system, we are investigating checkpoint activation mediated by the DNA mismatch repair proteins MutSalpha and MutLalpha in response to several DNA damaging agents including SN1 alkylators, fluorouracil, and cisplatin. DNA damage sensors that target specific types of DNA damage activate the ATR and ATM protein kinases. This, in turn, activates a cascade of signaling kinases including Chk1 and Chk2 that ultimately result in cell cycle arrest at the G2/M boundary. We are purifying recombinant human proteins involved in this damage response with the goal of defining the underlying molecular mechanism. We are also studying the oligomerization of a key tumor suppressor, p53. We have identified two amino acids at the C-terminus that affect formation of stable oligomers and are characterizing their effect on various functions of p53 in in vitro assays and in cells.