Genome function occurs within the context of a polymorphic three-dimensional (3D) chromatin landscape, composed of macromolecular structures ranging from tens to hundreds of nanometers in size – below the resolution limit of conventional light microscopy. Super-resolution 3D structured illumination microscopy (3D-SIM) allows multicolor imaging of entire cells with eight-fold increased volumetric resolution, and is uniquely well-suited to study the topological organization of mammalian cell nuclei. In my talk I will explain why 3D-SIM, in comparison to other microcopy techniques with higher spatial resolution, is particularly useful for quantifying spatial relationships within relatively large and densely packed biological objects such as the mammalian cell nucleus. I will also present our recent studies using 3D-SIM, which reveal organizational principles of active versus inactive X chromosomes, and the spatial relationships of both established and novel interactors of the long non-coding Xist RNA, the main effector of X inactivation. Finally, I will introduce our current efforts in systematic analysis of functional chromatin topology on the scale of Mb-sized domains, and the role of the cohesin complex in establishing and maintaining these topologies. These data highlight the power of 3D-SIM to both analyze the spatial and temporal relationships of nuclear factors in single cells, and to map these relationships onto the context of the 3D chromatin landscape.


Wednesday, May 6, 2015, 12:00. Seminar Room

Hosted by Prof. Melike Lakadamyali