A temperature-sensitive NUP116 null mutant forms a nuclear envelope seal over the yeast nuclear pore complex thereby blocking nucleocytoplasmic traffic.
NUP116 encodes a 116-kD yeast nuclear pore complex (NPC) protein that is not essential but its deletion (nup116 delta) slows cell growth at 23 degrees C and is lethal at 37 degrees C (Wente, S. R., M. P. Rout, and G. Blobel. 1992. J. Cell Biol. 119:705-723). Electron microscopic analysis of nup116 delta cells shifted to growth at 37 degrees C revealed striking perturbations of the nuclear envelope: a double membrane seal that was continuous with the inner and outer nuclear membranes had formed over the cytoplasmic face of the NPCs. Electron-dense material was observed accumulating between the cytoplasmic face of these NPCs and the membrane seal, resulting in "herniations" of the nuclear envelope around individual NPCs. In situ hybridization with poly(dT) probes showed the accumulation of polyadenylated RNA in the nuclei of arrested nup116 delta cells, sometimes in the form of punctate patches at the nuclear periphery. This is consistent with the electron microscopically observed accumulation of electron-dense material within the nuclear envelope herniations. We propose that nup116 delta NPCs remain competent for export, but that the formation of the membrane seals over the NPCs blocks nucleocytoplasmic traffic.
Wente
S R
SR
Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, New York 10021.
Blobel
G
G
D000818:Animals; D002470:Cell Survival / Q000502:physiology; D003593:Cytoplasm / Q000502:physiology* / Q000648:ultrastructure; D017353:Gene Deletion; D017403:In Situ Hybridization; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D008854:Microscopy, Electron; D009154:Mutation; D009685:Nuclear Envelope / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure*; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins / Q000235:genetics* / Q000502:physiology; D012313:RNA / Q000032:analysis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature
D008565:Membrane Proteins; C077730:NUP116 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D012313:RNA