有丝分裂中同源染色体正常分离是保证遗传信息正确传递的关键步骤。而中心粒稳定对这一过程有重要意义。INO80/SWR1染色质重塑复合物能通过组蛋白二聚体H2A/H2B和H2A.Z/H2B的置换及其他一系列重塑功能维持中心粒的稳定，从而保证同源染色体正常分离。以前期工作为基础，拟利用单分子技术，在核小体层面研究INO80/SWR1的重塑机制，侧重组蛋白及变体的置换机制。单分子技术在实时原位测量动态生物过程中有着其他技术难以比拟的优势，可以定量地对依赖ATP水解的分子马达的行为进行表征，提供其动力学信息。本项目拟以H2A/H2B和H2A.Z/H2B两种核小体为模板，实时追踪INO80/SWR1复合物在核小体DNA上移动及组蛋白置换的动态过程，深入剖析INO80重要亚基在重塑过程中的功能及参与组蛋白置换的机理。本研究将从分子机制上深入阐释INO80/SWR1在同源染色质分离中的调节作用。

Appropriate chromosome segregation in mitosis is critical to chromosomal stability. Chromosome segregation defects can result in aneuploidy，which is prevalent in cancer cells correlated with poor prognosis. INO80/SWR1 complexes are crucial for maintaining chromatin structure at centromeres by histones replacement between H2A/H2B and H2A.Z/H2B dimers. Based on our previous studies，we will employ single-molecule techniques combining optical tweezers and fluorescence microscopy, to investigate chromatin remodeling mechanism of INO80/SWR1 with emphasis on their histone replacement behaviors. Single-molecule techniques are especially suitable for studying the dynamic processes conducted by ATP-dependent motor proteins. By combining two technologies, we can qualitatively and quantitatively detect the histone variants replacements and at the same time measure the remodelers’ translocation speed, step size, loop size and processivities. We will utilize reconstituted nucleosomal DNA templates, by in trans adding INO80/SWR1 to the system, observe the dynamic interplay between nucleosomes and remodelers in a real-time manner. Furthermore, we will explore the roles of key subunits of INO80 complex in during chromatin remodeling. The study of histones replacements mechanism at single-molecule level will elucidate the regulatory mechanism of INO80/SWR1 complex in chromosome segregation.