PDF(Pubmed)
Abstract：
Error correction is central to many biological systems and is critical for protein function and cell health. During mitosis, error correction is required for the faithful inheritance of genetic material. When functioning properly, the mitotic spindle segregates an equal number of chromosomes to daughter cells with high fidelity. Over the course of spindle assembly, many initially erroneous attachments between kinetochores and microtubules are fixed through the process of error correction. Despite the importance of chromosome segregation errors in cancer and other diseases, there is a lack of methods to characterize the dynamics of error correction and how it can go wrong. Here, we present an experimental method and analysis framework to quantify chromosome segregation error correction in human tissue culture cells with live cell confocal imaging, timed premature anaphase, and automated counting of kinetochores after cell division. We find that errors decrease exponentially over time during spindle assembly. A coarse-grained model, in which errors are corrected in a chromosome-autonomous manner at a constant rate, can quantitatively explain both the measured error correction dynamics and the distribution of anaphase onset times. We further validated our model using perturbations that destabilized microtubules and changed the initial configuration of chromosomal attachments. Taken together, this work provides a quantitative framework for understanding the dynamics of mitotic error correction.
摘要：
纠错是许多生物系统的核心，对蛋白质功能和细胞健康至关重要。在有丝分裂期间，遗传物质的忠实遗传需要纠错。当功能正常时，有丝分裂纺锤体以高保真度将相等数量的染色体分离到子细胞。在主轴装配过程中，动静脉和微管之间的许多最初错误的附件是通过纠错过程固定的。尽管染色体分离错误在癌症和其他疾病中很重要，缺乏描述纠错动态以及它如何出错的方法。这里,我们提出了一种实验方法和分析框架，以量化人组织培养细胞中的染色体分离误差校正与活细胞共聚焦成像，定时早搏后期，细胞分裂后动静脉的自动计数。我们发现，在主轴装配过程中，误差会随着时间的推移而呈指数级下降。一个粗粒度的模型，其中错误以恒定的速率以染色体自主的方式得到纠正，可以定量解释测量的误差校正动态和后期开始时间的分布。我们使用扰动进一步验证了我们的模型，这些扰动使微管不稳定并改变了染色体附件的初始配置。一起来看,这项工作为理解有丝分裂误差校正的动力学提供了一个定量框架。
