Control of Chromosome Segregation by DNA Topoisomerase II

摘要 染色体分离错误导致非整倍体，从而导致出生缺陷和癌症。我们有 在酵母中定义了一种新的有丝分裂Topo II响应控制（TRC），当Topo II 活性不足以进行精确的染色体分离。这种TRC机制在人类中是保守的。 细胞，但尚未被广泛研究。TRC的激活由链中的缺陷触发 Topo II的通道反应，当酶通过其结构构象过渡太慢时。TRC 激活还需要Topo II的催化惰性C-末端结构域，其含有新的蛋白质- 与TRC信号蛋白结合的蛋白质相互作用基序。核心模型是那条异常链 通道可以在结构上从Topo II的催化核心转移到C-末端结构域， 作为信号产生支架来停止细胞周期。人与酵母TRC的保守性 反应提供了独特的机会，以确定TRC组件，并揭示机制， TRC激活。我们的目标是确定TRC激活的细胞/基因组位点，信号分子 参与和TRC激活的Topo II的C-末端结构域的机制。的结果予以 研究将影响转化研究的机会，因为我们将确定新的潜在治疗方法， 目标的我们的研究结果也将影响广泛使用的针对Topo II的治疗药物的使用。 因为我们将获得对Topo II抑制的细胞反应的机制性见解。初步数据 新开发的实验工具使我们处于一个独特的位置，以确定保守的 这一机制很少研究有丝分裂控制。

Abstract Chromosome segregation errors result in aneuploidy which causes birth defects and cancer. We have defined a new mitotic Topo II-responsive control (TRC) in yeast that delays the cell cycle when Topo II activity is insufficient for accurate chromosome segregation. This TRC mechanism is conserved in human cells, but has not been extensively studied. Activation of the TRC is triggered by defects in the strand passage reaction of Topo II, when the enzyme transits too slowly through its structural conformations. TRC activation also requires the catalytically inert C-terminal domain of Topo II, which contains novel protein- protein interaction motifs that bind to TRC signaling proteins. The central model is that aberrant strand passage may structurally transfer from the catalytic core of Topo II to the C-terminal domain which functions as a signal-generating scaffold to halt the cell cycle. The conservation between the human and yeast TRC responses provides unique opportunities to identify the TRC components and to reveal the mechanism of TRC activation. We aim to determine the cellular/genomic sites of TRC activation, the signaling molecules involved and the mechanism of TRC activation by the C-terminal domain of Topo II. The results of these studies will impact opportunities for translational research because we will identify new potential therapeutic targets. Our findings will also impact the use of widely prescribed therapeutic drugs that target Topo II because we will gain mechanistic insight into cellular responses to Topo II inhibition. The preliminary data and newly developed experimental tools place us in a unique position to determine the conserved mechanism of this scarcely studied mitotic control.