Hartwell L H, Weinert T A
Department of Genetics, University of Washington, Seattle 98195.
Science. 1989 Nov 3;246(4930):629-34. doi: 10.1126/science.2683079.
The events of the cell cycle of most organisms are ordered into dependent pathways in which the initiation of late events is dependent on the completion of early events. In eukaryotes, for example, mitosis is dependent on the completion of DNA synthesis. Some dependencies can be relieved by mutation (mitosis may then occur before completion of DNA synthesis), suggesting that the dependency is due to a control mechanism and not an intrinsic feature of the events themselves. Control mechanisms enforcing dependency in the cell cycle are here called checkpoints. Elimination of checkpoints may result in cell death, infidelity in the distribution of chromosomes or other organelles, or increased susceptibility to environmental perturbations such as DNA damaging agents. It appears that some checkpoints are eliminated during the early embryonic development of some organisms; this fact may pose special problems for the fidelity of embryonic cell division.
大多数生物体细胞周期中的事件被排列成依赖途径，其中晚期事件的启动依赖于早期事件的完成。例如，在真核生物中，有丝分裂依赖于DNA合成的完成。一些依赖关系可以通过突变得到缓解（有丝分裂可能在DNA合成完成之前发生），这表明这种依赖是由于一种控制机制，而不是这些事件本身的内在特征。在细胞周期中强制依赖的控制机制在这里被称为检查点。消除检查点可能导致细胞死亡、染色体或其他细胞器分配的错误，或增加对环境干扰（如DNA损伤剂）的易感性。似乎在一些生物体的早期胚胎发育过程中，一些检查点被消除了；这一事实可能给胚胎细胞分裂的保真度带来特殊问题。
