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.
