Chromatin Charting: Organization and Dynamics of Plant Nuclear DNA in situ

细胞核是亚细胞器，真核细胞内的大部分基因组信息都是在细胞核中组织的。尽管在过去的几年里，在生物体基因组测序方面取得了巨大的进步，但这些海量的遗传信息是如何在动植物的细胞核中存储和物理操作的仍然是一个谜。从使用杂交技术和显微镜工作的研究中，出现了一幅有组织的亚核结构的图景。一个主要的亚核结构是染色体，它包含有机体的基因组。最近，绿色荧光蛋白(GFP)作为染色体物质的活体标记的应用使动物和真菌的活细胞中的染色体可视化成为可能。该项目的目标是利用完整植物中的细胞绘制特定基因在每条染色体上的相对物理位置图，从而扩展GFP技术以了解亚核结构。为了实现可视化和绘制模式植物所有染色体上的基因的目标，拟南芥、GFP和该蛋白的两个不同颜色变体(黄色[YFP]和蓝色[BFP])将被用作转基因植物的活体标签。使用这三个不同的标记，将描述与基因表达和基因动员模式相关的基因组的物理组织。该项目是将这项技术确立为可视化基因组组织和基因表达之间关系的强大工具的第一步。虽然这种方法正在拟南芥模式植物中进行测试，但它应该提供必要的资源和工具，以解决所有植物中关于亚核结构和染色质动力学的基本问题。此外，这项工作的见解应该有助于我们理解全球基因调控以及所有真核生物中的表观遗传现象。

The nucleus is the subcellular organelle in which the bulk of the genomic information within an eukaryotic cell is organized. Although tremendous advances in sequencing genomes of organisms have taken place in the past few years, the way by which this vast amount of genetic information is stored and physically manipulated in the nuclei of plants and animals remains a mystery. From studies using hybridization technologies and microscopy work, a picture of an organized subnuclear structure has emerged. One major subnuclear structure is the chromosomes, which contain the genome of an organism. More recently, the application of the Green Fluorescent Protein (GFP) as an in vivo tag of chromosomal substances has allowed the visualization of chromosomes in live cells of animals and fungi. The goal for this project is to extend the GFP technology to understand subnuclear architecture by charting the relative physical position of specific genes on each of the chromosomes using cells within an intact plant. To achieve the objective of visualizing and charting the genes on all the chromosomes of a model plant, Arabidopsis, GFP and two different color variants (yellow [YFP] and blue [BFP]) of this protein will be used as in vivo tags in transgenic plants. Using the three distinct markers, the physical organization of the genome in relation to gene expression and gene mobilization patterns will be characterized. The project is a first step to establish this technology as a powerful tool to visualize the relationship between the genome organization and gene expression. While it is being tested in a model plant, Arabidopsis, this approach should provide the necessary resources and tools to address fundamental questions about subnuclear architecture and chromatin dynamics in all plants. Further, insights from this work should contribute to our understanding of global gene regulation as well as epigenetic phenomena in all eukaryotic organisms.