报告题目：Chromatinorganization principle of model species revealed by Hi-C data

报告人： 李立 博士

报告时间：2016年4月26日（周二）10:00

报告地点：逸夫楼C座314会议室

摘要：Next generationsequencing(NGS) is an emerging and rapidly developing technique which providesa very powerful tool for biological science. A lot of biological questionswhich are being studied by traditional experiments, now are all subject togenome-wide investigation in high-throughput way. NGS data is accumulating inan explosive way in both data quantity and data diversity, including ChIP-Seq,RNA-Seq, etc. One of the new sequencing technique is the so called Hi-C (High-throughputChromosome Conformation Capture). It aims to catch the chromatin structure byobserving spatial proximal DNA sequence ligation through pair-end sequencing.The resultant data can be represented as a 2-D matrix with entries (i,j) givingnumber of ligations observed between position i and j on the genome. We are oneof the first two groups generating and analyzing Hi-C data in drosophila. Wefound existence of topological associated domains (TADs). We developed a modelbased MCMC method to partition chromosomes into regions to maximize interactionenrichment within each region which is thus a TAD. About 1,100 TADs were foundin fly genome. At TAD borders, there is strong enrichment of gene density,active gene and binding of a lot of insulator proteins, together with activehistone modifications. To further decipher the principle of chromatin in fly,we did Hi-C on heat-shocked fly cell. TAD border becomes weaker globally witharchitectural proteins redistributed from TAD borders to inside TADs. Theincreased inter-TAD interactions are also enriched between promoter andenhancer of silence genes, which recruit polycomb and polycomb bodies innucleolus.

报告人简介：李立，理学博士学位, 博士后。1994年9月至1998年6月就读于武汉大学物理系，获物理学学士学位。1998年9月至2004年6月年就读于中科院高能物理研究所，主要从事宇宙线数据处理和分析工作，获粒子物理与核物理专业博士学位。2004年7月2007年6月在清华大学生物系从事博士后研究，转入生物信息学领域，进行生物网络分析，通过蛋白相互作用网络分析发现网络进化倾向于发生在网络中的稀疏部分。2007年7月至2011年4月就职于华中科技大学物理学院，副教授。2011年5月至2016年4月就职美国Emory University生物统计和生物信息学系，访问学者，博士后，期间和多个生物学实验室合作，围绕染色体结构和和表观遗传学，分析了包括ChIP-Seq, ATAC-Seq, ChIA-PET, RNA-Seq, 4C-seq, HiC-seq, BS-seq在内的大量新一代测序数据，是最早通过分析果蝇HiC数据发现其染色体拓扑结构域的两个课题组之一。迄今在生物信息学，生物学和高能物理等领域国际高水平学术期刊发表论文二十余篇。