Nuclear Pore Complex Number and Distribution throughout the Saccharomyces cerevisiae Cell Cycle by Three-Dimensional Reconstruction from Electron Micrographs of Nuclear Envelopes

摘要: The number of nuclear pore complexes (NPCs) in individual nuclei the yeast Saccharomyces cerevisiae was determined by computer-aided reconstruction entire from electron micrographs serially sectioned cells. Nuclei 32 haploid cells at various points cell cycle were modeled and found to contain between 65 182 NPCs. Morphological markers, such as shape shape, used determine stage being examined. NPC correlated with reveal that NPCs increases steadily, beginning G 1 -phase, suggesting assembly occurs continuously throughout cycle. However, accumulation envelope observed during cycle, indicated surface area, is not continuous same rate, density per unit area peaks apparent S-phase Analysis reconstructions also revealed no preferred NPC-to-NPC distance. large clusters over regions envelope. Interestingly, most pronounced early mitotic be associated spindle pole bodies, but functional significance this association unknown.