Three-dimensional organization of chromatin across the plant cell cycle

染色质作为一种在细胞内以微米为单位包装着大量遗传信息的大分子复合体，世纪以来一直受到人们的广泛关注。关于人类染色体的内部组织及其与基因组功能的关系，最近已经有了明确的认识，但关于染色质折叠沿着细胞周期和物种之间的变化，还有很多东西有待了解。细胞学成像和基因组测定的方法学进展使得以高密度和分辨率询问染色质接触概率和基因组位点之间的三维距离成为可能。我们的初步数据染色质接触频率在大麦有丝分裂染色体的百万倍分辨率表明小麦族物种和哺乳动物之间的中期染色体组织的根本差异。我们建议使用染色体构象捕获测序，超分辨率显微镜，荧光原位杂交和计算聚合物建模来研究大麦细胞周期中的染色质折叠。我们将测试染色质是否采取一个规则的螺线管构象在有丝分裂大麦染色体。这项研究将推导出一个实验验证的大麦染色体组织结构模型，并阐明大型植物和小型哺乳动物染色体之间的构象差异。

As the macromolecule complex that packages meters of genetic information in the micrometer-volume of a cell, chromatin have been under intense investigation for more than a century. Definite knowledge about the internal organization of human chromosomes and its relation to genome function has emerged recently, but much remains to be learned about the variation of chromatin folding along the cell cycle and between species. Methodological advances in cytological imaging and genomic assays have made it possible to interrogate chromatin contact probabilities and three-dimensional distances between genomic loci with high density and resolution. Our preliminary data on chromatin contact frequency at megabase resolution in barley mitotic chromosomes suggest fundamental differences in metaphase chromosome organization between Triticeae species and mammals. We propose to study chromatin folding throughout the cell cycle of barley using chromosome conformation capture sequencing, super-resolution microscopy, fluorescence in situ hybridization and computational polymer modeling. We will test whether chromatin adopts a regular solenoidal conformation in mitotic barley chromosomes. The proposed research will derive a experimentally validated structural model of chromosome organization in barley and elucidate conformational differences between large plant and smaller mammalian chromosomes.