Proliferation, Differentiation and Apoptosis in Villous Trophoblast at 13–41 Weeks of Gestation (Including Observations on Annulate Lamellae and Nuclear Pore Complexes)

The nuclear pore complex (NPC) and its relationship to the nuclear envelope (NE) was characterized in living cells using POM121–green fluorescent protein (GFP) and GFP-Nup153, and GFP–lamin B1. No independent movement of single pore complexes was found within the plane of the NE in interphase. Only large arrays of NPCs moved slowly and synchronously during global changes in nuclear shape, strongly suggesting mechanical connections which form an NPC network. The nuclear lamina exhibited identical movements. NPC turnover measured by fluorescence recovery after photobleaching of POM121 was less than once per cell cycle. Nup153 association with NPCs was dynamic and turnover of this nucleoporin was three orders of magnitude faster. Overexpression of both nucleoporins induced the formation of annulate lamellae (AL) in the endoplasmic reticulum (ER). Turnover of AL pore complexes was much higher than in the NE (once every 2.5 min). During mitosis, POM121 and Nup153 were completely dispersed and mobile in the ER (POM121) or cytosol (Nup153) in metaphase, and rapidly redistributed to an immobilized pool around chromatin in late anaphase. Assembly and immobilization of both nucleoporins occurred before detectable recruitment of lamin B1, which is thus unlikely to mediate initiation of NPC assembly at the end of mitosis.

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NEGATIVE STAINING AND ADENOSINE TRIPHOSPHATASE ACTIVITY OF ANNULATE LAMELLAE OF NEWT OOCYTES

The Journal of Cell Biology ◽

10.1083/jcb.42.2.519 ◽

1969 ◽

Vol 42 (2) ◽

pp. 519-533 ◽

Cited By ~ 45

Author(s):

Ulrich Scheer ◽

Werner W. Franke

Keyword(s):

Nuclear Envelope ◽

Pore Diameter ◽

Structural Data ◽

Negative Staining ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Triturus Alpestris ◽

Pore Complexes ◽

A Site

Semi-isolated annulate lamellae were prepared from single newt oocytes (Triturus alpestris) by a modified Callan-Tomlin technique. Such preparations were examined with the electron microscope, and the negative staining appearance of the annulate lamellae is described. The annulate lamellae can be detected either adhering to the nuclear envelope or being detached from it. Sometimes they are observed to be connected with slender tubular-like structures interpreted as parts of the endoplasmic reticulum. The results obtained from negative staining are combined with those from sections. Especially, the structural data on the annulate lamellae and the nuclear envelope of the very same cell were compared. Evidence is presented that in the oocytes studied the two kinds of porous cisternae, namely annulate lamellae and nuclear envelope, are markedly distinguished in that the annulate lamellae exhibit a much higher pore frequency (generally about twice that found for the corresponding nuclear envelope) and have also a relative pore area occupying as much as 32% to 55% of the cisternal surface (compared with 13% to 22% in the nuclear envelopes). The pore diameter and all other ultrastructural details of the pore complexes, however, are equivalent in both kinds of porous cisternae. Like the annuli of the nuclear pore complexes of various animal and plant cells, the annuli of the annulate lamellae pores reveal also an eightfold symmetry of their subunits in negatively stained as well as in sectioned material. Furthermore, the annulate lamellae are shown to be a site of activity of the Mg-Na-K-stimulated ATPase.

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Assembly of nuclear pore complexes and annulate lamellae promotes normal pronuclear development in fertilized mammalian oocytes

Journal of Cell Science ◽

10.1242/jcs.111.19.2841 ◽

1998 ◽

Vol 111 (19) ◽

pp. 2841-2854 ◽

Cited By ~ 5

Author(s):

P. Sutovsky ◽

C. Simerly ◽

L. Hewitson ◽

G. Schatten

Keyword(s):

Cell Types ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Oocyte Activation ◽

Nuclear Pores ◽

Microtubule Inhibitor ◽

Cytoplasmic Transport ◽

Oocyte Cytoplasm ◽

Pore Complexes

In addition to functional nuclear pore complexes engaged in nucleo-cytoplasmic transport, the cytoplasmic stacks of pore complexes, called annulate lamellae, exist in numerous cell types. Although both annulate lamellae and nuclear pore complexes are present in fertilized mammalian oocytes, their relative roles in the process of fertilization and preimplantation development are not known. Using epifluorescence and electron microscopy, we explored their fate during bovine fertilization. The assembly of annulate lamellae in bovine oocytes was triggered by sperm-oocyte binding and continued concomitantly with the incorporation of the nuclear pores in the nuclear envelopes of the developing male and female pronuclei. This process was also induced by the parthenogenetic activation of metaphase-II-arrested oocytes. Depletion of Ca2+, previously implicated in oocyte activation and in the insertion of pore complexes into the nuclear envelope, prevented the formation of nuclear pore complexes, but not the assembly of annulate lamellae in oocyte cytoplasm. Injection of the nuclear pore antagonist, wheat germ agglutinin, into the cytoplasm of mature oocytes that were subsequently fertilized caused the arrest of pronuclear development, indicating the requirement of nuclear pore complexes for normal pronuclear development. Treatment of the fertilized oocytes with the microtubule inhibitor, nocodazole, prevented gathering of annulate lamellae around the developing pronuclei, insertion of nuclear pores into their nuclear envelopes, and further pronuclear development. The formation of the male pronuclei was reconstituted in Xenopus egg extracts and reflected the behavior of nuclear pores during natural fertilization. These data suggest that nuclear pore complexes are required for normal pronuclear development from its beginning up until pronuclear apposition. Annulate lamellae may be involved in the turnover of nuclear pore complexes during fertilization, which is in turn facilitated by the reorganization of oocyte microtubules and influx of Ca2+ into oocyte cytoplasm.

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Insertional Mutation of the Drosophila Nuclear Lamin Dm0 Gene Results in Defective Nuclear Envelopes, Clustering of Nuclear Pore Complexes, and Accumulation of Annulate Lamellae

The Journal of Cell Biology ◽

10.1083/jcb.137.5.1001 ◽

1997 ◽

Vol 137 (5) ◽

pp. 1001-1016 ◽

Cited By ~ 145

Author(s):

Bettina Lenz-Böhme ◽

Jasmine Wismar ◽

Silke Fuchs ◽

Rita Reifegerste ◽

Erich Buchner ◽

...

Keyword(s):

P Element ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Severe Phenotype ◽

Nuclear Lamins ◽

First Intron ◽

Nuclear Lamin ◽

The Central Nervous System ◽

Pore Complexes

Nuclear lamins are thought to play an important role in disassembly and reassembly of the nucleus during mitosis. Here, we describe a Drosophila lamin Dm0 mutant resulting from a P element insertion into the first intron of the Dm0 gene. Homozygous mutant animals showed a severe phenotype including retardation in development, reduced viability, sterility, and impaired locomotion. Immunocytochemical and ultrastructural analysis revealed that reduced lamin Dm0 expression caused an enrichment of nuclear pore complexes in cytoplasmic annulate lamellae and in nuclear envelope clusters. In several cells, particularly the densely packed somata of the central nervous system, defective nuclear envelopes were observed in addition. All aspects of the mutant phenotype were rescued upon P element-mediated germline transformation with a lamin Dm0 transgene. These data constitute the first genetic proof that lamins are essential for the structural organization of the cell nucleus.

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Cdk1 and Okadaic Acid-sensitive Phosphatases Control Assembly of Nuclear Pore Complexes in Drosophila Embryos

Molecular Biology of the Cell ◽

10.1091/mbc.e05-07-0642 ◽

2005 ◽

Vol 16 (11) ◽

pp. 5152-5162 ◽

Cited By ~ 52

Author(s):

Evgeny A. Onischenko ◽

Natalia V. Gubanova ◽

Elena V. Kiseleva ◽

Einar Hallberg

Keyword(s):

Okadaic Acid ◽

Dynamic Equilibrium ◽

In Vivo Model ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Pore Complexes ◽

Drosophila Embryos

Disassembly and reassembly of the nuclear pore complexes (NPCs) is one of the major events during open mitosis in higher eukaryotes. However, how this process is controlled by the mitotic machinery is not clear. To investigate this we developed a novel in vivo model system based on syncytial Drosophila embryos. We microinjected different mitotic effectors into the embryonic cytoplasm and monitored the dynamics of disassembly/reassembly of NPCs in live embryos using fluorescently labeled wheat germ agglutinin (WGA) or in fixed embryos using electron microscopy and immunostaining techniques. We found that in live embryos Cdk1 activity was necessary and sufficient to induce disassembly of NPCs as well as their cytoplasmic mimics: annulate lamellae pore complexes (ALPCs). Cdk1 activity was also required for keeping NPCs and ALPCs disassembled during mitosis. In agreement recombinant Cdk1/cyclin B was able to induce phosphorylation and dissociation of nucleoporins from the NPCs in vitro. Conversely, reassembly of NPCs and ALPCs was dependent on the activity of protein phosphatases, sensitive to okadaic acid (OA). Our findings suggest a model where mitotic disassembly/reassembly of the NPCs is regulated by a dynamic equilibrium of Cdk1 and OA-sensitive phosphatase activities and provide evidence that mitotic phosphorylation mediates disassembly of the NPC.

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A biochemical and immunological comparison of nuclear and cytoplasmic pore complexes

Journal of Cell Science ◽

10.1242/jcs.109.7.1813 ◽

1996 ◽

Vol 109 (7) ◽

pp. 1813-1824 ◽

Cited By ~ 2

Author(s):

A. Ewald ◽

U. Kossner ◽

U. Scheer ◽

M.C. Dabauvalle

Keyword(s):

Nuclear Envelope ◽

Nuclear Pore Complex ◽

Transport Processes ◽

Immunogold Electron Microscopy ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Nuclear Surface ◽

Annulate Lamellae ◽

Binding Studies ◽

Pore Complexes

Pore complexes are not confined to the nuclear envelope but can also be found in the cytoplasm of numerous cell types in the form of annulate lamellae (AL). We have induced formation of AL by exposure of rat cells (line RV) to sublethal doses of the antimitotic drug vinblastine sulfate, and compared the distribution of several nuclear pore complex proteins (nucleoporins) in the nuclear envelope and AL by immunocytochemistry, cytochemical lectin binding studies and immunoblot analyses of nuclear and AL-enriched fractions. All the antibodies used yielded punctate nuclear surface staining in immunofluorescence microscopy which is characteristic for nuclear pore complex components. When we applied antibodies against the nucleoporin p62, AL were visualized as numerous cytoplasmic dot-like structures. Immunogold electron microscopy confirmed the correspondence of the cytoplasmic bodies with stacks of AL. Antibodies to constituents of the cytoplasmic (nup180) and nucleoplasmic (nup153) filaments extending from both sides of nuclear pore complexes also stained the AL, indicating that pore complexes are intrinsically asymmetric assemblies independent of their specific intracellular topology. By contrast, AL were negative with five different antibodies against the transmembrane nuclear pore glycoprotein gp210 and the lectin concanavalin A (ConA) known to bind to the oligosaccharide side chains of gp210. Similarly, there was no staining of the AL with antibodies to the other nuclear pore membrane protein so far known in higher eukaryotes, POM121. Immunoblot analyses confirmed the presence of p62, nup180 and nup153 in both the nuclear and AL fractions and the absence of gp210 and POM121 from AL. Our results do not support the generally held view that gp210 and POM121 function in anchoring the pore complex scaffold to the pore membrane. Rather, they point to a role for these proteins in transport processes through the nuclear pore complexes. Since AL are not involved in nucleocytoplasmic transport processes they may lack components of the transport machinery.

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The molecular chaperone DNAJB6 provides surveillance of FG-Nups and is required for interphase nuclear pore complex biogenesis

10.1101/2021.10.26.465890 ◽

2021 ◽

Author(s):

E. F. Elsiena Kuiper ◽

Paola Gallardo ◽

Tessa Bergsma ◽

Muriel Mari ◽

Maiara Kolbe Musskopf ◽

...

Keyword(s):

Molecular Chaperone ◽

Intrinsically Disordered Proteins ◽

Disordered Proteins ◽

Nuclear Pore ◽

Permeability Barrier ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Intrinsically Disordered ◽

Pore Complexes

Biogenesis of nuclear pore complexes (NPCs) includes the formation of the permeability barrier composed of phenylalanine-glycine-rich nucleoporins (FG-Nups) that regulate the selective passage/crossing of biomolecules. The FG-Nups are intrinsically disordered and prone to liquid-liquid phase separate and aggregate when isolated. It has remained largely unclear how FG-Nups are protected from making inappropriate interactions during NPC biogenesis. We found that DNAJB6, a molecular chaperone of the heat shock protein network, formed foci next to NPCs. The number of these foci decreases upon removal of proteins involved in the early steps of interphase NPC biogenesis. Reversely, when this process is stalled in the last steps, the number of DNAJB6-containing foci increases and they could be identified as herniations at the nuclear envelope (NE). Immunoelectron tomography showed that DNAJB6 localizes inside the lumen of the herniations arising at NPC biogenesis intermediates. Interestingly, loss of DNAJB6 results in annulate lamellae, which are structures containing partly assembled NPCs associated with disturbances in NPC biogenesis. We find that DNAJB6 binds to FG-Nups and can prevent the aggregation of the FG-region of several FG-Nups in cells and in vitro. Together, our data show that DNAJB6 provides quality control during NPC biogenesis and is the first molecular chaperone that is involved in the surveillance of native intrinsically disordered proteins, including FG-Nups.

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Abnormal assembly of annulate lamellae and nuclear pore complexes coincides with fertilization arrest at the pronuclear stage of human zygotic development

Human Reproduction ◽

10.1093/humrep/deg114 ◽

2003 ◽

Vol 18 (3) ◽

pp. 576-582 ◽

Cited By ~ 14

Author(s):

V.Y. Rawe

Keyword(s):

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Annulate Lamellae ◽

Pore Complexes

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Nuclear Envelope Dynamics During Mitosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103188 ◽

1988 ◽

Vol 46 ◽

pp. 224-225

Author(s):

Brian Burke

Keyword(s):

Nuclear Envelope ◽

Membrane Vesicles ◽

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Animal Cells ◽

Interphase Chromosome ◽

Lamin B ◽

Chromosome Architecture ◽

Complex Membrane ◽

Pore Complexes

The nuclear envelope is a complex membrane structure that forms the boundary of the nuclear compartment in eukaryotes. It regulates the passage of macromolecules between the two compartments and may be important for organizing interphase chromosome architecture. In interphase animal cells it forms a remarkably stable structure consisting of a double membrane ouerlying a protein meshwork or lamina and penetrated by nuclear pore complexes. The latter form the channels for nucleocytoplasmic exchange of macromolecules, At the onset of mitosis, however, it rapidly disassembles, the membranes fragment to yield small vesicles and the lamina, which is composed of predominantly three polypeptides, lamins R, B and C (MW approx. 74, 68 and 65 kDa respectiuely), breaks down. Lamins B and C are dispersed as monomers throughout the mitotic cytoplasm, while lamin B remains associated with the nuclear membrane vesicles.

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Pore relations: nuclear pore complexes and nucleocytoplasmic exchange

Essays in Biochemistry ◽

10.1042/bse0360075 ◽

2000 ◽

Vol 36 ◽

pp. 75-88 ◽

Cited By ~ 18

Author(s):

Michael P. Rout ◽

John D. Aitchison

Keyword(s):

Nuclear Pore ◽

Nuclear Pore Complexes ◽

Pore Complexes

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