In eukaryotic cells, tens of thousands of genes are packed in a small volume of the nucleus. The genome is organized in chromosomes, which occupy specific nuclear volumes referred to as chromosome territories. This organization is maintained, even though there are no sub-compartments in the nucleus.

The organization of the genome in the nucleus is crucial for cellular functions such as gene regulation. Therefore, understanding the organizational mechanisms and the role of specific proteins is extremely important. The dynamics of the nucleus content is fundamental for understanding its appropriate function, and the nuclear structure is strongly related to the dynamic properties.

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 of different genomic regions across several time orders, and implement Continuous Photobleaching (CP) measurements which provide crucial information on the mobility and binding properties of the proteins. Through CP, we compare the effect of specific nuclear structural protein on chromatin dynamics.

We found lately that chromatin diffusion in normal cells is slow and anomalous and that depletion of lamin A protein results in faster, normal diffusion dynamics. . In contrast, the depletion of LAP2α slows the chromatin dynamics and reduces the fraction of bound lamin A. These observations strongly suggest that the dynamic structure of the chromatin in the nucleus is mediated by different structural proteins.

We continue the study by mapping more other proteins that may be responsible for chromatin organization, including lamin B1, lamin B2 and BAF. Thus, through dynamic fluorescence measurements we can map the regulating networks of chromatin motion.