Chromatin dynamics governed by a set of nuclear structural proteins

  Anat Vivante  ,  Irena Bronshtein  ,  Yuval Garini  
Physics Department & Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel

In eukaryotic cells, tens of thousands of genes are packed in the small volume of the nucleus. The genome itself is organized in chromosomes that occupy specific volumes referred to as chromosome territories. This organization is preserved throughout the cell cycle, even though there are no sub-compartments in the nucleus itself. This organization, which is still not fully understood, is crucial for a large number of cellular functions such as gene regulation, DNA breakage repair and error-free cell division.

The nuclear structure is strongly related to the dynamic properties. Hence, the dynamics of the nucleus content is fundamental for understanding its appropriate function. Understanding the mechanisms that are responsible for maintaining chromosomes within their territories and the role of specific proteins is extremely important.

We use live imaging methods to characterize the dynamic properties of the chromatin and its organization in living cells. More specifically, we use single particle tracking (SPT) of different genomic regions, and implement Continuous Photobleaching (CP) measurements which provide crucial information on the mobility and binding properties of the proteins.

Through these methods, we analyze the effect of specific nuclear proteins on chromatin dynamics. Finally, we suggest a model of chromatin organization and develop a new type of diagram for mapping and analyzing the regulating networks of chromatin organization.