title: Structural characterization of altered nucleoporin Nup153 expression in human cells by thin-section electron microscopy.
abstract: Nuclear pore complexes (NPCs) span the 2 membranes of the nuclear envelope (NE) and facilitate nucleocytoplasmic exchange of macromolecules. NPCs have a roughly tripartite structural organization with the so-called nuclear basket emanating from the NPC scaffold into the nucleoplasm. The nuclear basket is composed of the 3 nucleoporins Nup153, Nup50, and Tpr, but their specific role for the structural organization of this NPC substructure is, however, not well established. In this study, we have used thin-section transmission electron microscopy to determine the structural consequences of altering the expression of Nup153 in human cells. We show that the assembly and integrity of the nuclear basket is not affected by Nup153 depletion, whereas its integrity is perturbed in cells expressing high concentrations of the zinc-finger domain of Nup153. Moreover, even mild over-expression of Nup153 is coinciding with massive changes in nuclear organization and it is the excess of the zinc-finger domain of Nup153 that is sufficient to induce these rearrangements. Our data indicate a central function of Nup153 in the organization of the nucleus, not only at the periphery, but throughout the entire nuclear interior.
authors.affiliation: a Institute for Molecular Biology and Medicine ; Université Libre de Bruxelles ; Charleroi , Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Duheron
authors.forename: Guillaume
authors.initials: G
authors.lastname: Chatel
authors.forename: Ursula
authors.initials: U
authors.lastname: Sauder
authors.forename: Vesna
authors.initials: V
authors.lastname: Oliveri
authors.forename: Birthe
authors.initials: B
authors.lastname: Fahrenkrog
mesh_terms: D002466:Cell Nucleolus / Q000235:genetics / Q000648:ultrastructure*; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008854:Microscopy, Electron; D022022:Nuclear Pore / Q000235:genetics / Q000648:ultrastructure; D028861:Nuclear Pore Complex Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000648:ultrastructure; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000648:ultrastructure
chemical_list: C079377:NUP153 protein, human; C121702:NUP50 protein, human; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C073597:TPR protein, human
keywords: BIR, baculovirus IAP repeat; DAPI, 4',6-diamidino-2-phenylindole; DMEM, Dulbecco's modified Eagle's medium; EM, electron microscopy; FBS, foetal bovine serum; FG, phenylalanine-glycine; GFP, green fluorescent protein; IAP, inhibitor of apoptosis; MDa, megadalton; MEM, minimal essential medium; Min, minute; NE, nuclear envelope; NPC,nuclear pore complex; Nup, nuclear pore protein, nucleoporin; Nup153; Nup50; PBS, phosphate buffered saline; PVDF, Polyvinylidene difluoride; RT, room temperature; TBS, (Tris(hydroxymethyl)-aminomethan) buffered saline; TEM,transmission electron microscopy; Tpr; Tpr, translocated promoter region; XIAP, X-linked inhibitor of apoptosis; electron microscopy; kDa, kilodalton; nuclear basket; nuclear pore complex; nucleoporin; siRNA, small interfering ribonucleic acid