Building a minimal nucleus to understand structure and mechanics of assembly

Alexander Von Appen

MPI of Molecular Cell Biology and Genetics

The nucleus, the largest organelle in human cells, plays a crucial role in protecting, organizing, and regulating our genome. Despite its complexity, it undergoes remarkable dynamics during cell division: as the cell enters mitosis, nuclear organization dissolves, leading to the detachment of the nuclear membrane from chromatin. The nucleoplasm and cytoplasm merge into a single entity, while the spindle distributes chromosomes to form daughter cells. Following this “open” mitosis, the entire organelle reassembles within minutes, prompting the central question: what molecular mechanisms drive nuclear self-assembly?

I will present our latest efforts to reconstitute nuclear self-assembly processes, which we study structurally using cryo-electron tomography and mechanically using optical tweezers. Specifically, I will show how ESCRT proteins assemble to close the nuclear membrane and how DNA is organized at the chromatin–nuclear membrane interface.

About speaker

PhD, EMBL Heidelberg, with Martin Beck, studying the structure of the human nuclear pore complex PostDoc, UCSF San Francisco, with Adam Frost, studying the role of phase separation in ESCRT-mediated nuclear membrane assembly Since 2021, Research Group Leader at the Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany