CAREER: The Biomechanics of Chromosome Movement

这个项目的科学目标是了解、模拟和操纵细胞分裂过程中染色体分离的生物力学。真核细胞的有丝分裂依赖于沿着长圆柱形微管网络移动染色体的分子机器。这一过程必须严格执行和严格监管；缺乏精确度会导致子代细胞之间遗传物质的不均匀分配，可能导致细胞死亡或其他异常。本项目从两个方面探讨这个问题：1)计算模型，以预测染色体和微管之间相互作用的特征、速度和动力学；2)生物物理实验，以测试和完善模型。前一种方法从一个简单的随机热力学模型开始，该模型描述了推动染色体运动的力的起源和协调。在该模型的指导下，后一项活动侧重于染色体运动的起源和物理性质。使用先进的光学梯度陷阱(光镊子)在体外操纵与染色体相互作用的微管，将测量作用力和机械性能。补充实验将通过应用超短激光脉冲在有丝分裂装置中产生有针对性的局部破坏的技术来检查体内的染色体运动。切断染色体结合的微管和染色体片段所引起的变化将与模型预测进行比较，以阐明机械特性。这些实验将量化染色体的机械和力产生特性：1)承受和响应拉伸载荷，以保持与微管的连接；2)沿着微管移动；3)在有丝分裂的不同阶段移动到适当的位置；以及4)形成并维持与有丝分裂纺锤体的连接。教育目标包括将研究和教学相结合，鼓励具有强大量化技能的学生探索细胞生物学问题，并为他们提供严格的跨学科背景，使他们在这一追求中脱颖而出。主要目标是继续发展定量细胞生物学和细胞与分子生物力学的课程，开发与定量细胞生物学配套的实验室部分，并开发新的教学资源。这包括继续开发一套广泛的互联网资源，这些资源将演变为定量细胞生物学新的本科生文本的框架，该框架将与其他研究人员的意见一起构建。这一教育计划将对大学扩大生物医学工程本科培养的努力产生重大影响。一个主要的长期利益将是改善工程和物理方法在细胞生物学和生物技术研究中的转移和应用。

The scientific goal of this project is to understand, model, and manipulate the biomechanics of chromosomal separation during cell division. Eukaryotic mitosis depends on molecular machines that move chromosomes along a network of long cylindrical microtubules. This process must be precisely performed and tightly regulated; lack of precision, leading to unequal distribution of genetic material between daughter cells, can result in cell death or other abnormalities. This project approaches this problem from two fronts: 1) computational modeling to predict the character, speed, and dynamics of interactions between chromosomes and microtubules; and 2) biophysical experimentation to test and refine the models. The former approach starts with a simple stochastic, thermodynamic model that describes the origin and coordination of the forces that move chromosomes. Guided by the model, the latter activities focus on the origin and physical properties of chromosome movements. Using an advanced optical gradient trap (optical tweezers) to manipulate microtubules interacting with chromosomes in vitro, forces and mechanical properties will be measured. Complementary experiments will examine chromosome movement in vivo by applying technology in which an ultra-short laser pulse creates targeted, localized disruptions within the mitotic apparatus. The changes that result from severing chromosome-bound microtubules and fragments of chromosome will be compared with modeling predictions to elucidate mechanical properties. These experiments will quantify mechanical and force generating properties that allow chromosomes to: 1) bear and respond to tensile loads to maintain connections with microtubules; 2) move along microtubules; 3) move to appropriate location during the different phases of mitosis; and 4) form and maintain connections with the mitotic spindle. Educational goals include integrating research and teaching to encourage students with strong quantitative skills to pursue cell biology problems, and to provide them with a rigorous interdisciplinary background so they excel at this pursuit. Principal aims are the continued development of classes in Quantitative Cell Biology and Cellular and Molecular Biomechanics, developing a laboratory segment to accompany Quantitative Cell Biology, and developing new teaching resources. This includes continued development of an extensive set of Internet resources, which will evolve into the framework for a new undergraduate text in Quantitative Cell Biology, which will be constructed with input from other investigators. This educational plan will have a significant impact on universities' efforts to expand undergraduate training in Biomedical Engineering. A major long-term benefit will be improved transfer and application of engineering and physics approaches to cell biology and biotechnology research.