| 报告题目： |
Studies on the dynamics and regulation of 30-nm chromatin fiber by single molecule force spectroscopy |
| 报告人： |
李伟 副研究员 |
| 报告人单位： |
中科院物理所 |
| 报告时间： |
5月31日（周五）上午10点 |
| 报告地点： |
科技楼北410 |
| 报告人简介： |
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李伟，中科院物理所副研究员，博士生导师。2006年获得中科院物理所博士学位。目前，主要从事生物物理交叉学科的研究，利用磁镊单分子力谱技术，并结合冷冻电镜、原子力显微镜等手段，跟踪生物大分子（DNA和蛋白质）的动态结构，分析其在生命活动中的分子机制及功能。在JACS、 PRL、Molecular Cell、Genes & Development、PRE等刊物上发表学术论文30余篇。最近在染色质动态结构和调控方面取得一系列进展，相关工作被引述为Nature Reviews封面。2017获得中科院前沿重点项目资助，2018年获得北京市科学技术进步二等奖。 |
| 报告摘要： |
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In eukaryotes, the packaging of genomic DNA into chromatin plays a critical role in gene regulation. However, the dynamic organization of chromatin fibers and its regulatory mechanisms remain poorly understood. Using single molecule magnetic tweezers, we reveal that the tetranucleosomes-on-a-string appears as a stable secondary structure which is attenuated by histone chaperone FACT. Furthermore, we reveal that FACT’s subunit SSRP1 is responsible for maintenance of the nucleosome integrity by holding H3/H4 tetramer on DNA. In contrast, the large subunit SPT16 destabilizes the nucleosome structure by displacing H2A/H2B dimers. Our findings provide mechanistic insights by which the two subunits of FACT coordinate with each other to fulfill its functions. To trace the details of chromatin folding and unfolding dynamics and to reveal the spatial relationship between DNA and histones, we are developing a new method of combing single molecule magnetic tweezers and single molecule FRET. |
