We used various model systems to interrogate the structure and dynamics of chromatin in live cells. For instance, the Wu lab used 3D MFM-PALM/STORM to interrogate the architecture of individual Cse4 histone molecules within the centromere cluster of budding yeast, with nanometer resolution.
3D representation of histone Cse4 distribution in anaphase budding yeast cells (Wisniewski, Hajj et al. 2014).
More globally, we interrogated the statistical properties of chromatin spatial organization in fixed and live cells using various imaging methods. We described the spatial organization of chromatin as well as its mobility dynamics, in order to build a model consistent with known genome folding properties from other techniques. Such a model will constitute an important conceptual tool to understand how Transcription Factors explore the nuclear space, and whether/how do long-range chromatin interactions take place.
Time-Lapse microscopy of a pattern of photoactivated H2B labeled with photoactivatable GFP (PA-GFP) in the nucleus of a U2Os cell. Image acquisition time, 200ms; inter frame time, 45 minutes (Recamier, Izeddin et al. 2014).