Nuclear envelope localization of human UNC84A does not require nuclear lamins

Nuclear lamins are nucleus-specific intermediate filaments (IF) found at the inner nuclear membrane (INM) of the nuclear envelope (NE). Together with nuclear envelope transmembrane proteins, they form the nuclear lamina and are crucial for gene regulation and mechanical robustness of the nucleus and the whole cell. Recently, we characterized Dictyostelium NE81 as an evolutionarily conserved lamin-like protein, both on the sequence and functional level. Here, we show on the structural level that the Dictyostelium NE81 is also capable of assembling into filaments, just as metazoan lamin filament assemblies. Using field-emission scanning electron microscopy, we show that NE81 expressed in Xenopous oocytes forms filamentous structures with an overall appearance highly reminiscent of Xenopus lamin B2. The in vitro assembly properties of recombinant His-tagged NE81 purified from Dictyostelium extracts are very similar to those of metazoan lamins. Super-resolution stimulated emission depletion (STED) and expansion microscopy (ExM), as well as transmission electron microscopy of negatively stained purified NE81, demonstrated its capability of forming filamentous structures under low-ionic-strength conditions. These results recommend Dictyostelium as a non-mammalian model organism with a well-characterized nuclear envelope involving all relevant protein components known in animal cells.

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The expression, lamin-dependent localization and RNAi depletion phenotype for emerin inC. elegans

Journal of Cell Science ◽

10.1242/jcs.115.5.923 ◽

2002 ◽

Vol 115 (5) ◽

pp. 923-929 ◽

Cited By ~ 4

Author(s):

Yosef Gruenbaum ◽

Kenneth K. Lee ◽

Jun Liu ◽

Merav Cohen ◽

Katherine L. Wilson

Keyword(s):

Nuclear Envelope ◽

Molecular Mechanisms ◽

Cell Types ◽

Growth Conditions ◽

Rnai Phenotype ◽

Lamin B ◽

C Elegans ◽

Nuclear Lamins ◽

First Time

Emerin belongs to the LEM-domain family of nuclear membrane proteins, which are conserved in metazoans from C. elegans to humans. Loss of emerin in humans causes the X-linked form of Emery-Dreifuss muscular dystrophy(EDMD), but the disease mechanism is not understood. We have begun to address the function of emerin in C. elegans, a genetically tractable nematode. The emerin gene (emr-1) is conserved in C. elegans. We detect Ce-emerin protein in the nuclear envelopes of all cell types except sperm, and find that Ce-emerin co-immunoprecipitates with Ce-lamin from embryo lysates. We show for the first time in any organism that nuclear lamins are essential for the nuclear envelope localization of emerin during early development. We further show that four other types of nuclear envelope proteins, including fellow LEM-domain protein Ce-MAN1, as well as Ce-lamin, UNC-84 and nucleoporins do not depend on Ce-emerin for their localization. This result suggests that emerin is not essential to organize or localize the only lamin (B-type) expressed in C. elegans. We also analyzed the RNAi phenotype resulting from the loss of emerin function in C. elegans under laboratory growth conditions, and found no detectable phenotype throughout development. We propose that C. elegans is an appropriate system in which to study the molecular mechanisms of emerin function in vivo.

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Nuclear Organization in Stress and Aging

Cells ◽

10.3390/cells8070664 ◽

2019 ◽

Vol 8 (7) ◽

pp. 664 ◽

Cited By ~ 11

Author(s):

Romero-Bueno ◽

de la Cruz Ruiz ◽

Artal-Sanz ◽

Askjaer ◽

Dobrzynska

Keyword(s):

Gene Expression ◽

Nuclear Envelope ◽

Nuclear Organization ◽

3 Dimensional ◽

Cellular Processes ◽

Nuclear Lamins ◽

Nuclear Composition ◽

Histone Modifiers ◽

And Function ◽

Gene Expression Alterations

The eukaryotic nucleus controls most cellular processes. It is isolated from the cytoplasm by the nuclear envelope, which plays a prominent role in the structural organization of the cell, including nucleocytoplasmic communication, chromatin positioning, and gene expression. Alterations in nuclear composition and function are eminently pronounced upon stress and during premature and physiological aging. These alterations are often accompanied by epigenetic changes in histone modifications. We review, here, the role of nuclear envelope proteins and histone modifiers in the 3-dimensional organization of the genome and the implications for gene expression. In particular, we focus on the nuclear lamins and the chromatin-associated protein BAF, which are linked to Hutchinson–Gilford and Nestor–Guillermo progeria syndromes, respectively. We also discuss alterations in nuclear organization and the epigenetic landscapes during normal aging and various stress conditions, ranging from yeast to humans.

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Closing the (nuclear) envelope on the genome: How nuclear lamins interact with promoters and modulate gene expression

BioEssays ◽

10.1002/bies.201300138 ◽

2013 ◽

Vol 36 (1) ◽

pp. 75-83 ◽

Cited By ~ 40

Author(s):

Philippe Collas ◽

Eivind G. Lund ◽

Anja R. Oldenburg

Keyword(s):

Gene Expression ◽

Nuclear Envelope ◽

Nuclear Lamins

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Integral Membrane Proteins of the Nuclear Envelope Are Dispersed throughout the Endoplasmic Reticulum during Mitosis

The Journal of Cell Biology ◽

10.1083/jcb.137.6.1199 ◽

1997 ◽

Vol 137 (6) ◽

pp. 1199-1210 ◽

Cited By ~ 160

Author(s):

Li Yang ◽

Tinglu Guan ◽

Larry Gerace

Keyword(s):

Membrane Proteins ◽

Nuclear Envelope ◽

Nuclear Membrane ◽

Mammalian Cells ◽

Polyclonal Antibodies ◽

Integral Membrane Proteins ◽

Immunogold Electron Microscopy ◽

Nuclear Pore ◽

Nuclear Lamins ◽

Nuclear Membranes

We have analyzed the fate of several integral membrane proteins of the nuclear envelope during mitosis in cultured mammalian cells to determine whether nuclear membrane proteins are present in a vesicle population distinct from bulk ER membranes after mitotic nuclear envelope disassembly or are dispersed throughout the ER. Using immunofluorescence staining and confocal microscopy, we compared the localization of two inner nuclear membrane proteins (laminaassociated polypeptides 1 and 2 [LAP1 and LAP2]) and a nuclear pore membrane protein (gp210) to the distribution of bulk ER membranes, which was determined with lipid dyes (DiOC6 and R6) and polyclonal antibodies. We found that at the resolution of this technique, the three nuclear envelope markers become completely dispersed throughout ER membranes during mitosis. In agreement with these results, we detected LAP1 in most membranes containing ER markers by immunogold electron microscopy of metaphase cells. Together, these findings indicate that nuclear membranes lose their identity as a subcompartment of the ER during mitosis. We found that nuclear lamins begin to reassemble around chromosomes at the end of mitosis at the same time as LAP1 and LAP2 and propose that reassembly of the nuclear envelope at the end of mitosis involves sorting of integral membrane proteins to chromosome surfaces by binding interactions with lamins and chromatin.

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DNA from Drosophila melanogaster β-heterochromatin binds specifically to nuclear lamins in vitro and the nuclear envelope in situ

Gene ◽

10.1016/0378-1119(96)00002-9 ◽

1996 ◽

Vol 171 (2) ◽

pp. 171-176 ◽

Cited By ~ 36

Author(s):

Ella A. Baricheva ◽

Miguel Berrios ◽

Sergei S. Bogachev ◽

Igor V. Borisevich ◽

Eugenia R. Lapik ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Nuclear Envelope ◽

Nuclear Lamins

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Nucleoplasmic Lamin C Rapidly Accumulates at Sites of Nuclear Envelope Rupture with BAF and cGAS

10.1101/2022.01.05.475028 ◽

2022 ◽

Author(s):

Yohei Kono ◽

Stephen A. Adam ◽

Karen Reddy ◽

Yixian Zheng ◽

Ohad Medalia ◽

...

Keyword(s):

Nuclear Envelope ◽

Live Cell Imaging ◽

Cell Imaging ◽

Nuclear Lamina ◽

Structural Components ◽

Cell Nuclei ◽

Embryonic Fibroblasts ◽

Nuclear Lamins ◽

Laser Microirradiation

In mammalian cell nuclei, the nuclear lamina (NL) underlies the nuclear envelope (NE) to maintain nuclear structure. The nuclear lamins, the major structural components of the NL, are involved in the protection against NE rupture induced by mechanical stress. However, the specific role of the lamins in repair of NE ruptures has not been fully determined. Our analyses using immunofluorescence and live-cell imaging revealed that lamin C but not the other lamin isoforms rapidly accumulated at sites of NE rupture induced by laser microirradiation in mouse embryonic fibroblasts. The immunoglobulin-like fold domain and the NLS were required for the recruitment from the nucleoplasm to the rupture sites with the Barrier-to-autointegration factor (BAF). The accumulation of nuclear BAF and cytoplasmic cyclic GMP-AMP (cGAMP) synthase (cGAS) at the rupture sites was in part dependent on lamin A/C. These results suggest that nucleoplasmic lamin C, BAF and cGAS concertedly accumulate at sites of NE rupture for repair.

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Nuclear Lamins a and B1

The Journal of Cell Biology ◽

10.1083/jcb.151.6.1155 ◽

2000 ◽

Vol 151 (6) ◽

pp. 1155-1168 ◽

Cited By ~ 253

Author(s):

Robert D. Moir ◽

Miri Yoon ◽

Satya Khuon ◽

Robert D. Goldman

Keyword(s):

Green Fluorescent Protein ◽

Nuclear Envelope ◽

Daughter Cell ◽

Fluorescent Protein ◽

Lamin A ◽

Cell Nuclei ◽

Nuclear Lamins ◽

Daughter Cells ◽

Lamin B1 ◽

Green Fluorescent

At the end of mitosis, the nuclear lamins assemble to form the nuclear lamina during nuclear envelope formation in daughter cells. We have fused A- and B-type nuclear lamins to the green fluorescent protein to study this process in living cells. The results reveal that the A- and B-type lamins exhibit different pathways of assembly. In the early stages of mitosis, both lamins are distributed throughout the cytoplasm in a diffusible (nonpolymerized) state, as demonstrated by fluorescence recovery after photobleaching (FRAP). During the anaphase-telophase transition, lamin B1 begins to become concentrated at the surface of the chromosomes. As the chromosomes reach the spindle poles, virtually all of the detectable lamin B1 has accumulated at their surfaces. Subsequently, this lamin rapidly encloses the entire perimeter of the region containing decondensing chromosomes in each daughter cell. By this time, lamin B1 has assembled into a relatively stable polymer, as indicated by FRAP analyses and insolubility in detergent/high ionic strength solutions. In contrast, the association of lamin A with the nucleus begins only after the major components of the nuclear envelope including pore complexes are assembled in daughter cells. Initially, lamin A is found in an unpolymerized state throughout the nucleoplasm of daughter cell nuclei in early G1 and only gradually becomes incorporated into the peripheral lamina during the first few hours of this stage of the cell cycle. In later stages of G1, FRAP analyses suggest that both green fluorescent protein lamins A and B1 form higher order polymers throughout interphase nuclei.

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Purification and immunological detection of pea nuclear intermediate filaments: evidence for plant nuclear lamins

Journal of Cell Science ◽

10.1242/jcs.103.2.407 ◽

1992 ◽

Vol 103 (2) ◽

pp. 407-414 ◽

Cited By ~ 2

Author(s):

A.K. McNulty ◽

M.J. Saunders

Keyword(s):

Nuclear Envelope ◽

Intermediate Filaments ◽

Plant Cells ◽

Nuclear Lamina ◽

Animal Cells ◽

Nuclear Lamins ◽

Antigenic Characterization ◽

Major Structural Component ◽

Nuclear Envelope Assembly ◽

Type V

A major structural component of the inner face of the nuclear envelope in vertebrates and invertebrates is the nuclear lamina, an array of 1–3 extrinsic membrane proteins, lamins A, B and C. These proteins are highly homologous to intermediate filaments and are classified as type V. We report the first purification, antigenic characterization and immunocytochemical localization of putative plant lamin proteins from pea nuclei. We conclude that plant cells contain this ancestral class of intermediate filaments in their nuclei and that regulation of nuclear envelope assembly/disassembly and mitosis in plants may be similar to that in animal cells.

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Fibroblasts lacking nuclear lamins do not have nuclear blebs or protrusions but nevertheless have frequent nuclear membrane ruptures

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1812622115 ◽

2018 ◽

Vol 115 (40) ◽

pp. 10100-10105 ◽

Cited By ~ 20

Author(s):

Natalie Y. Chen ◽

Paul Kim ◽

Thomas A. Weston ◽

Lovelyn Edillo ◽

Yiping Tu ◽

...

Keyword(s):

Dna Damage ◽

Nuclear Envelope ◽

Nuclear Membrane ◽

Membrane Integrity ◽

Nuclear Lamina ◽

Virtual Absence ◽

Inner Nuclear Membrane ◽

Nuclear Lamins ◽

Transmission Electron ◽

Nuclear Lamin

The nuclear lamina, an intermediate filament meshwork lining the inner nuclear membrane, is formed by the nuclear lamins (lamins A, C, B1, and B2). Defects or deficiencies in individual nuclear lamin proteins have been reported to elicit nuclear blebs (protrusions or outpouchings of the nuclear envelope) and increase susceptibility for nuclear membrane ruptures. It is unclear, however, how a complete absence of nuclear lamins would affect nuclear envelope morphology and nuclear membrane integrity (i.e., whether nuclear membrane blebs or protrusions would occur and, if not, whether cells would be susceptible to nuclear membrane ruptures). To address these issues, we generated mouse embryonic fibroblasts (MEFs) lacking all nuclear lamins. The nuclear lamin-deficient MEFs had irregular nuclear shapes but no nuclear blebs or protrusions. Despite a virtual absence of nuclear blebs, MEFs lacking nuclear lamins had frequent, prolonged, and occasionally nonhealing nuclear membrane ruptures. By transmission electron microscopy, the inner nuclear membrane in nuclear lamin-deficient MEFs have a “wavy” appearance, and there were discrete discontinuities in the inner and outer nuclear membranes. Nuclear membrane ruptures were accompanied by a large increase in DNA damage, as judged by γ-H2AX foci. Mechanical stress increased both nuclear membrane ruptures and DNA damage, whereas minimizing transmission of cytoskeletal forces to the nucleus had the opposite effects.

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