Structural and functional analysis of chromatin compaction

染色质压实是细胞中的一个关键过程，调节了许多生物反应，如基因表达、染色质与核孔的附着、端粒稳定性和DNA修复。尽管潜在的机制尚不清楚，但人们认为染色质调节因子的结合限制了多种因子对DNA的访问。与染色质压实有关的因素与癌症和神经系统疾病等疾病有关。目前，在Speck实验室的工作一直集中在阐明染色质压实过程中的结构变化及其后果。该博士项目旨在利用重组染色质的低温电镜分析，充分阐明一组特定染色质调节因子对染色质压实的分子机制，并推断这一过程是如何被连接蛋白调节的。生物物理技术将被用来研究染色质的动力学和它的压缩形式。一组疾病相关的染色质压实因子突变将被评估，以研究这些突变如何影响染色质结构。在博士项目的过程中，各种DNA序列将被用作染色质组装的模板，包括在人类基因组的异染色质区域发现的序列，或与疾病相关的序列。这个项目将有助于提供对染色质的结构理解，特别是描述异染色质的构象景观。

Chromatin compaction is a key process in the cell, modulating many biological reactions such as gene expression, chromatin attachment to the nuclear pore, telomere stability and DNA repair. Although the underlying mechanisms are not well known, it is thought that the binding of chromatin regulators restricts access of a variety of factors to DNA. The role of factors involved in chromatin compaction is linked to diseases such as cancer and neurological disorders. Currently, work in the Speck lab has been focussing on elucidating the structural changes during chromatin compaction and their consequences. This PhD project will aim to fully elucidate the molecular mechanisms of chromatin compaction by a specific set of chromatin regulators using cryo-EM analysis of reconstituted chromatin, and to deduce how this process is modulated by linker histones. Biophysical techniques will be employed to investigate the dynamics of chromatin and its compacted form. A cohort of disease-associated mutants of chromatin compaction factors will be assessed in order to investigate how these mutants impact on chromatin architecture. During the course of the PhD project various DNA sequences will be used as a template for chromatin assembly, including sequences found in heterochromatic regions of the human genome, or sequences related to disease. This project will help to provide a structural understanding of chromatin and describe in particular the conformational landscape of hetero-chromatin.