Organization of the genome in the nucleus

The nucleus of the eukaryotic cell contains tens of thousands of genes (~23,000 in human) organized on chromosomes. This crowded environment contains packed genetic material in a small volume. The genetic information on the DNA is continously functioning either during the replication of the cell or the on-going transcription to RNA molecules leading to protein translation. These processes depend on the ability of protein factors to locate and interact with specific DNA sequence within this packed nucleus, as well as on the organization and structure of chromatin in the nucleus.Telomeres dynamics Fig1 PRL

Telomeres are the end caps of chromosomes in eukaryotic cells. They are important for maintaining chromosome organization and integrity throughout the cell cycle. They are protected by protein factors that are called shelterin and can bind to other organelles in the nucleus. We are studying the telomere organization and dynamics in the nucleus. It shades light on the role of telomeres in genome organization, and the coordination of physical structures and biological processes in the nucleus.

Lately, we measured the trajectories of telomeres in the nucleus in a very broad time range by combining a few acquisition methods. see late publication (figure reproduced with permission from PRL). We found that the telomere dynamics is subdiffusive at short times and it changes to normal diffusion at longer times. We explained it by the reptation model and the local binding mechanism with a wide but finite distribution of waiting times. These findings have important biological implications with respect to the genome organization in the nucleus.