Chair: Tiago F. Outeiro

Prof. Tom Kirchhausen from the Department of Cell Biology, Harvard Medical School, Boston will talk about “Mitotic formation of nuclear pore complexes”.

Abstract

Frontier optical-imaging modalities exemplified by the lattice light-sheet microscope invented by Eric Betzig sets new visualization standards for analyzing and understanding sub-cellular processes in the complex and dynamic three-dimensional environment of living-cells in isolation and within tissues of an organism. By using ultra-thin sheets of light to rapidly illuminate biological samples with extremely low photon doses, 3D experiments previously limited to seconds or minutes by photo-bleaching or by photo-toxicity, can now be done at diffraction limited resolution and high-temporal precision with unprecedented duration of minutes or hours. We believe this ability to image with minimal perturbations is ideally suited to support hypothesis-generating research geared towards new discoveries. The talk will illustrate how use of lattice light-sheet microscopy allowed us to uncover a templating process mediating the formation of nuclear pores during mitosis. We ‘saw’ incomplete mitotic dissociation of all NPCs in dividing cells yielding reusable building blocks consisting of octameric inner and outer ring nuclear subassemblies; the building blocks remained associated with fenestrated mitotic ER sheets and through telophase templated post-mitotic NPCs assembly during the attachment of the fenestrated ER sheets to decondensed chromatin. Because these building blocks are ‘immortal’ and survive many cycles of cell division, they were able to template assembly of many post-mitotic NPC during subsequent cell cycles.