CELL CYCLE CHECKPOINT CONTROL IN RESPONSE TO DNA DAMAGE

监测基因组完整性的机制的存在 并在DNA损伤的情况下导致细胞周期停滞 被描述为检查点控制。在以下情况下未能阻止细胞周期 DNA受损会导致突变的传播或丢失 染色体材料。而DNA之前的细胞周期停滞现象 复制(G1期停滞)或DNA复制(G2期停滞)很好 建立了与检测相结合的信号转导途径 DNA损伤对细胞周期进程的控制只是 开始被阐明。拟议的项目旨在描述 在有丝分裂反应之前导致细胞周期停滞的检查点 DNA损伤，最初是通过Chk1蛋白的特征 P56chk1在裂殖酵母中的表达。细胞缺乏一个 功能性Chk1基因在有丝分裂之前不能阻止细胞周期 DNA损伤发生时，尝试通过细胞周期 破坏DNA，随后死亡。其他几个基因的产物是 也是细胞周期停止所必需的，以应对DNA损伤；然而， 尽管知道RAD基因产物的初级序列， 人们对它们的功能知之甚少。作为一种蛋白激酶，p56chk1是一种 理想的蛋白质，用来启动机械特性的研究 这条路。确定p56chk1在细胞周期调节中的作用 在DNA损伤后被捕，两个互补的研究方向将是 开展：进行生物化学研究，以确定对 P56chk1的活性和基因筛选以识别与之相关的蛋白质 P56chk1相互作用。 分裂和萌芽酵母已经成功地用作工具 人类基因的识别通过基因的进化控制进展 细胞周期由于所涉及的分子的进化保守所致。 许多信号转导通路的结构都是保守的 也是。因此，依赖p56chk1的细胞周期的特征 逮捕路径应该被证明是一个有用的范例 人细胞周期停滞DNA损伤的通路偶联检测 细胞。关于细胞周期停滞的机制的信息将是 对于设计更有效的覆盖路径的方法至关重要 肿瘤细胞的化疗治疗。

The presence of a mechanism which monitors the integrity of the genome and leads to cell cycle arrest in the event of DNA damage has been described as checkpoint control. Failure to arrest the cell cycle when DNA is damaged can lead to the propagation of mutations or loss of chromosomal material. While the phenomena of cell cycle arrest before DNA replication (G1 arrest) or after DNA replication (G2 arrest) is well- established, the signal transduction pathway which couples the detection of DNA damage to control of progression through the cell cycle is only beginning to be elucidated. The proposed project aims to characterize the checkpoint which leads to cell cycle arrest prior to mitosis in response to DNA damage, initially through the characterization of the chk1 protein kinase (p56chk1) in Schizosaccharomyces pombe. Cells which lack a functional chk1 gene fail to arrest the cell cycle prior to mitosis when DNA damage takes place, attempt to proceed through the cell cycle with damaged DNA and subsequently die. The products of several other genes are also required for cell cycle arrest in response to DNA damage; however, despite knowledge of the primary sequence of the rad gene products, little is known about their function. As a protein kinase, p56chk1 is an ideal protein with which to initiate a mechanistic characterization of this pathway. To determine the role of p56chk1 in mediating cell cycle arrest following DNA damage, two complementary lines of research will be carried out: biochemical studies to characterize the regulation of the activity of p56chk1 and genetic screens to identify proteins with which p56chk1 interacts. The fission and budding yeasts have been used successfully as tools for the identification of human genes which govern progression through the cell cycle due to evolutionary conservation of the molecules involved. The architecture of many signal transduction pathways has been conserved as well. Thus, characterization of the p56chk1 dependent cell cycle arrest pathway should prove to be a useful paradigm for dissecting the pathway coupling detection of DNA damage to cell cycle arrest in human cells. Information regarding the mechanism of cell cycle arrest will be vital for the design of more effective ways of overriding the pathway for chemotherapeutic treatment of tumor cells.