CHECKPOINT CONTROL OF ENTRY INTO MITOSIS

（部分由NIH GMS 40198支持，C.L.里德尔）。 在这 我们正在使用激光显微手术来确定RAD-9 在脊椎动物体细胞中，检查点是关闭的。 研究 酵母揭示，当染色体受损时， 通过辐射。 然而，我们从实验室的工作中得知， 脊椎动物的体细胞不会以同样的方式反应。 而是在 当染色体被切断时，这些细胞的有丝分裂正常进行 在核膜破裂后进行激光显微手术。 在 目前的研究，我们正在研究局部损伤的影响， DNA和细胞质控制核膜破裂。 我们发现 在中期前期细胞中破坏DNA会使它们回到间期， 但是在晚期前期细胞上的相同实验并不能抑制 进入有丝分裂。 我们还发现照射局部区域 532 nm光照射细胞质的100%，也可引起中期，但不引起晚期 前期细胞返回间期。 这些结果已经 摘要到1997年ASCB会议，并透露，RAD 9 检查点系统在脊椎动物细胞中被废除， 核膜破裂 科尔，R.W.，A.霍贾科夫角科格斯韦尔和 C.L.里德尔。 04 The Dog（1997） 进入前中期可以通过照射 用强绿色激光照射细胞质。 摩尔 生物细胞8：

(Supported in part by NIH GMS 40198 to C.L. Rieder). In this study we are using laser microsurgery to determine when the RAD-9 checkpoint is turned off in vertebrate somatic cells. Studies in yeast reveal that mitosis is arrested when the chromosomes are damaged by irradiation. However, we know from work in our laboratory that vertebrate somatic cells do not respond the same way. Rather, in these cells mitosis proceeds normally when the chromosomes are severed by laser microsurgery after nuclear envelope breakdown. In the current study we are examining the effect of localized damage to the DNA and cytoplasm in controlling nuclear envelope breakdown. We find that damaging DNA in mid prophase cells returns them to interphase, but that the same experiment on late prophase cells does not inhibit entry into mitosis. We also found that irradiating the local regions of the cytoplasm with 532 nm light also caused mid but not late prophase cells to return to interphase. These results have been abstracted to the 1997 ASCB meeting and reveal that the RAD 9 checkpoint system is abrogated in vertebrate cells shortly prior to nuclear envelope breakdown. Cole, R.W., A. Khodjakov, C. Cogswell and C.L. Rieder. (1997) Progression of mid (but not late) prophase cells into prometaphase can be transiently reversed by irradiating the cytoplasm with intense green laser light. Mole. Biol. Cell 8: