THE NUCLEAR-ENVELOPE OF THE YEAST SACCHAROMYCES-CEREVISIAE

This chapter reviews the progress that has been made in identifying the structures, functions, and molecules of the yeast nuclear envelope. Yeast nuclei can be efficiently isolated by a variety of methods based on the enzymatic digestion of a cell wall followed by lysis in a buffer complemented with 18% Ficoll as an osmotic stabilizer. The yeast nuclear envelope does not break down during mitosis. Spindle microtubules emanate from the spindle pole bodies (SPB), which are microtubule-organizing centers (MTOCs) embedded in the nuclear envelope. The nuclear pore complexes (NPCs) in yeast are elaborate, supramolecular assemblies that span the nuclear envelope at sites where the outer and inner membranes are joined. The number of nuclear pores in the envelope can vary depending on the cell type. The overall structure and diameter of an NPC are highly conserved throughout evolution. Nuclear pores are considered the major sites of entry and exit for nucleocytoplasmic transport. Yeast undergoes a closed mitosis, and the nuclear envelope is not disassembled or assembled during mitotic division. © 1992 Academic Press Inc.