COLL 17 |
| Hans Oberleithner, Institute of Physiology, Institute of Physiology, University of Münster, Robert-Koch-Str. 27a, 48149 Münster, Germany |
| The eukaryotic cell nucleus is wrapped in the nuclear envelope (NE) punctured by nuclear pore complexes (NPCs). NPCs are studied most adequately in NE isolated manually from Xenopus Laevis oocyte nuclei. NE is spread on a flat support and individual NPCs are imaged using atomic force microscopy (AFM). Stimulation with steroid hormones initiates a cascade of changes at single NPC level: 1. Binding of putative receptors (100 kDa) to the cytoplasmic surface of NPCs within 2 minutes after stimulation. 2. Disappearance of the receptors within 10 minutes. 3. Appearance of large (1000 kDa) plugs in NPC central channels, 20 minutes after hormone stimulation. Plugs are most likely ribonucleoproteins containing mRNA. Plugs can be harvested by the AFM tip and used for further analysis. In conclusion, nuclear envelopes could serve as biological nanoarrays in which molecules on the way into and out of the nucleus can be trapped, isolated and studied.
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Nanoscale Imaging of Biological Systems
Division of Colloid and Surface Chemistry |