Mechanisms to move and steer chromosomes

移动和操纵染色体的机制

基本信息

批准号：
10214634
负责人：
P. TODD STUKENBERG
金额：
$ 32.3万
依托单位：
UNIVERSITY OF VIRGINIA
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10214634
关键词：
Actins Address Anaphase Bacteria Behavior Binding Biological Assay CENP-E protein Cell division Cells Cellular biology Chromatids Chromosomes Complex Coupled Development Drug Targeting Ensure Eukaryota Event Family Feedback Fluorescence Resonance Energy Transfer Future Generations Genetic Materials Genomic Instability Gout Harvest Human Human Chromosomes In Vitro Kinesin Kinetochores Ligation Malignant Neoplasms Measures Mechanics Metaphase Metaphase Plate Methods Microtubule Depolymerization Microtubule Polymerization Microtubules Mitosis Mitotic spindle Modeling Motor Movement Names Nature Pathway interactions Pharmaceutical Preparations Phosphorylation Plasmids Plus End of the Microtubule Polymers Power stroke Process Prometaphase Proteins Regulatory Pathway Relapse Signal Transduction Sister Slide Structure System Testing Therapeutic Tubulin Vinca Alkaloids Work Yeasts arm calponin cancer cell chemotherapy chromosome movement depolymerization dimer experimental study foot fungus in vivo mutant polymerization segregation single molecule taxane tomography

项目摘要

Project Summary/Abstract We will elucidate the mechanisms that power the movements of chromosomes on the mitotic spindle and the mechanisms that control the direction of these movements. Fungi use the ring shaped Dam1 complex, which works with multiple “arm-like” Ndc80 complexes to move chromosomes. This ring can be pushed poleward by a “power stroke” generated when depolymerizing microtubules curve at the plus end to power the movement of chromosomes. However, it is unclear how most eukaryotes, including humans, power chromosome movement since they lack the Dam1 ring complex. We visualized purified human Ndc80 and Ska complexes on microtubules by EM tomography to elucidate the structure of the human kinetochore-microtubule attachment. These new structures orient Ska on microtubules and also suggest Ndc80 complexes oligomerize on microtubules to form a structure we have named the “sliding foot”. This new structure suggests testable mechanisms for how metazoans kinetochores are pushed by the curvature of a depolymerizing microtubule like yeast. We have developed two in vivo assays that allow us to measure the formation of the sliding feet and to measure the chromosome movements that require Ska. In addition, we will employ single molecule assays to measure the requirement of the sliding foot to generate force in vitro. Using these new assays, we will identify the mechanism that powers the movements of human chromosomes on the mitotic spindle. Surprisingly, on most chromosomes only one of the two sister kinetochores has sliding feet. This is exciting because chromosome movements require one sister to actively engage depolymerizing ~20 microtubules to pull chromosomes, while its sister must passively attach to growing microtubules. We will identify the regulatory pathways that generate the asymmetry of sliding foot formation on the two sister kinetochores. We hypothesize that these pathways not only regulate sliding foot formation but can also ensure that one sister has depolymerizing microtubules while the microtubules bound to its sister kinetochore are polymerizing. We will build on these findings to identify the mechanisms that direct chromosome movements either towards or away from poles on the mitotic spindle. It is important to understand these basic mechanisms that lie at the center of the chromatid segregation to determine how cancer cells lower the fidelity of mitosis to generate genomic instability and to increase the efficacy of anti-tubulin chemotherapeutics.

项目摘要/摘要我们将阐明染色体在有丝分裂主轴上的运动和控制这些运动方向的机制。真菌使用环形的DAM1复合物，使用多个“手臂状” NDC80复合物来移动染色体。该戒指可以通过当取代微管曲线在加上末端为移动动力时，产生的“动力冲程”会产生染色体。但是，目前尚不清楚大多数真核生物如何，包括人类，动力染色体运动由于他们缺乏大坝1环复合体。我们在上面看到了纯化的人NDC80和SKA复合体通过EM层析成像的微纤维阐明了人动型微纤维附着的结构。这些新结构在微管上取代SKA，还建议NDC80复合物在微管形成我们称为“滑动脚”的结构。这种新结构建议可测试解聚微管的曲率如何推动后生动物学的机制像酵母一样。我们已经开发了两个体内测定，使我们能够测量滑动脚的形成并测量需要SKA的染色体运动。此外，我们将采用单分子测量滑动脚的需求以在体外产生力。使用这些新测定，我们将确定为人类染色体在有丝分裂纺锤体上运动的机制。令人惊讶的是，在大多数染色体上，两个姐妹Kinetochores中只有一个滑动脚。这是令人兴奋的因为染色体运动要求一个姐姐积极接合约20微管拉染色体，而其姐姐必须被动地与生长的微管相连。我们将确定在两个姐妹动物学上产生滑动脚形成的不对称性的调节途径。我们假设这些途径不仅调节滑动脚的形成，还可以确保一个姐姐具有解聚微管，而与其姊妹动力学结合的微管则是聚合。我们将基于这些发现以确定将染色体运动指向或远离有丝分裂主轴上的极点。重要的是要了解这些基本机制位于染色单体隔离的中心确定癌细胞如何降低有丝分裂的忠诚度产生基因组不稳定性并增加抗微管蛋白化学治疗剂的功效。