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

1992 ◽  
Vol 103 (2) ◽  
pp. 407-414 ◽  
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.

scholarly journals Supramolecular Structures of the Dictyostelium Lamin NE81

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 162
Author(s):  
Marianne Grafe ◽  
Petros Batsios ◽  
Irene Meyer ◽  
Daria Lisin ◽  
Otto Baumann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nuclear Envelope ◽  
Model Organism ◽  
Super Resolution ◽  
Nuclear Lamina ◽  
Stimulated Emission ◽  
Structural Level ◽  
Animal Cells ◽  
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.

scholarly journals A role for nuclear lamins in nuclear envelope assembly

2001 ◽  
Vol 154 (1) ◽  
pp. 61-70 ◽  
Author(s):  
Reynold I. Lopez-Soler ◽  
Robert D. Moir ◽  
Timothy P. Spann ◽  
Reimer Stick ◽  
Robert D. Goldman
Keyword(s):  
Nuclear Envelope ◽  
Molecular Interactions ◽  
Nuclear Membrane ◽  
Nuclear Lamina ◽  
Chromatin Decondensation ◽  
Nuclear Lamins ◽  
Nuclear Membranes ◽  
Terminal Domain ◽  
Nuclear Envelope Assembly

The molecular interactions responsible for nuclear envelope assembly after mitosis are not well understood. In this study, we demonstrate that a peptide consisting of the COOH-terminal domain of Xenopus lamin B3 (LB3T) prevents nuclear envelope assembly in Xenopus interphase extracts. Specifically, LB3T inhibits chromatin decondensation and blocks the formation of both the nuclear lamina–pore complex and nuclear membranes. Under these conditions, some vesicles bind to the peripheral regions of the chromatin. These “nonfusogenic” vesicles lack lamin B3 (LB3) and do not bind LB3T; however, “fusogenic” vesicles containing LB3 can bind LB3T, which blocks their association with chromatin and, subsequently, nuclear membrane assembly. LB3T also binds to chromatin in the absence of interphase extract, but only in the presence of purified LB3. Additionally, we show that LB3T inhibits normal lamin polymerization in vitro. These findings suggest that lamin polymerization is required for both chromatin decondensation and the binding of nuclear membrane precursors during the early stages of normal nuclear envelope assembly.

The structure and function of the nuclear lamins

1995 ◽  
Vol 53 ◽  
pp. 762-763
Author(s):  
R.D. Goldman ◽  
A. Goldman ◽  
S. Khuon ◽  
M. Montag-Lowy ◽  
R. Moir ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Lamina ◽  
Structure And Function ◽  
Supramolecular Organization ◽  
Intermediate Filament Proteins ◽  
Nuclear Envelope Breakdown ◽  
Nuclear Lamins ◽  
Interphase Cells ◽  
Type V ◽  
And Function

The nuclear lamins are the Type V intermediate filament proteins comprising the nuclear lamina. The lamina is located subjacent to the nucleoplasmic face of the nuclear envelope where it interfaces with chromatin. The lamins are major karyoskeletal proteins which are thought to play important roles in the formation and maintenance of nuclear shape and architecture, as well as in the supramolecular organization of chromatin. The lamins have long been thought to be stable polymeric constituents of the interphase nuclear matrix, due to their insolubility in solutions containing detergents and high salt concentrations. During mitosis, however, the nuclear lamins depolymerize during nuclear envelope breakdown. Subsequently, the lamins repolymerize around the decondensing chromosomes as the nuclear envelope reassembles at the end of mitosis. Although there is a significant amount known about the properties and potential functions of the lamins during mitosis, surprisingly little is known about their properties during interphase. In light of this, we have undertaken experiments which are aimed at determining the properties of the lamins in interphase cells.

scholarly journals A Balance Between Intermediate Filaments and Microtubules Maintains Nuclear Architecture in the Cardiomyocyte

2020 ◽  
Vol 126 (3) ◽  
Author(s):  
Julie Heffler ◽  
Parisha P. Shah ◽  
Patrick Robison ◽  
Sai Phyo ◽  
Kimberly Veliz ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Intermediate Filaments ◽  
Genome Organization ◽  
Contractile Function ◽  
Nuclear Architecture ◽  
Super Resolution ◽  
Nuclear Lamina ◽  
Linc Complex ◽  
Spectrin Repeat ◽  
Balance Of Forces

Rationale: Mechanical forces are transduced to nuclear responses via the linkers of the nucleoskeleton and cytoskeleton (LINC) complex, which couples the cytoskeleton to the nuclear lamina and associated chromatin. While disruption of the LINC complex can cause cardiomyopathy, the relevant interactions that bridge the nucleoskeleton to cytoskeleton are poorly understood in the cardiomyocyte, where cytoskeletal organization is unique. Furthermore, while microtubules and desmin intermediate filaments associate closely with cardiomyocyte nuclei, the importance of these interactions is unknown. Objective: Here, we sought to determine how cytoskeletal interactions with the LINC complex regulate nuclear homeostasis in the cardiomyocyte. Methods and Results: To this end, we acutely disrupted the LINC complex, microtubules, actin, and intermediate filaments and assessed the consequences on nuclear morphology and genome organization in rat ventricular cardiomyocytes via a combination of super-resolution imaging, biophysical, and genomic approaches. We find that a balance of dynamic microtubules and desmin intermediate filaments is required to maintain nuclear shape and the fidelity of the nuclear envelope and lamina. Upon depletion of desmin (or nesprin [nuclear envelope spectrin repeat protein]-3, its binding partner in the LINC complex), polymerizing microtubules collapse the nucleus and drive infolding of the nuclear membrane. This results in DNA damage, a loss of genome organization, and broad transcriptional changes. The collapse in nuclear integrity is concomitant with compromised contractile function and may contribute to the pathophysiological changes observed in desmin-related myopathies. Conclusions: Disrupting the tethering of desmin to the nucleus results in a loss of nuclear homeostasis and rapid alterations to cardiomyocyte function. Our data suggest that a balance of forces imposed by intermediate filaments and microtubules is required to maintain nuclear structure and genome organization in the cardiomyocyte.

The Cell's Biological Rods and Ropes

MRS Bulletin ◽  
1999 ◽  
Vol 24 (10) ◽  
pp. 27-31 ◽  
Author(s):  
David Boal
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Chemical Composition ◽  
Intermediate Filaments ◽  
Plant Cells ◽  
Cell Type ◽  
Animal Cells ◽  
Limited Variation ◽  
A Cell ◽  
Mechanical Elements

Despite a variety of shapes and sizes, the generic mechanical structure of cells is remarkably similar from one cell type to the next. All cells are bounded by a plasma membrane, a fluid sheet that controls the passage of materials into and out of the cell. Plant cells and bacteria reinforce this membrane with a cell wall, permitting the cell to operate at an elevated osmotic pressure. Simple cells, such as the bacterium shown in Figure 1a, possess a fairly homogeneous interior containing the cell's genetic blueprint and protein workhorses, but no mechanical elements. In contrast, as can be seen in Figure 1b, plant and animal cells contain internal compartments and a filamentous cytoskeleton—a network of biological ropes, cables, and poles that helps maintain the cell's shape and organize its contents.Four principal types of filaments are found in the cytoskeleton: spectrin, actin, microtubules, and a family of intermediate filaments. Not all filaments are present in all cells. The chemical composition of the filaments shows only limited variation from one cell to another, even in organisms as diverse as humans and yeasts. Membranes have a more variable composition, consisting of a bi-layer of dual-chain lipid molecules in which are embedded various proteins and frequently a moderate concentration of cholesterol. The similarity of the cell's mechanical elements in chemical composition and physical characteristics encourages us to search for universal strategies that have developed in nature for the engineering specifications of the cell. In this article, we concentrate on the cytoskeleton and its filaments.

scholarly journals A lamin-independent pathway for nuclear envelope assembly.

1990 ◽  
Vol 111 (6) ◽  
pp. 2247-2259 ◽  
Author(s):  
J W Newport ◽  
K L Wilson ◽  
W G Dunphy
Keyword(s):  
Nuclear Envelope ◽  
Dna Synthesis ◽  
Structural Integrity ◽  
Nuclear Lamina ◽  
Limited Extent ◽  
Nuclear Pores ◽  
Nuclear Assembly ◽  
Nuclear Envelope Assembly ◽  
A Cell ◽  
Nuclear Envelope Formation

The nuclear envelope is composed of membranes, nuclear pores, and a nuclear lamina. Using a cell-free nuclear assembly extract derived from Xenopus eggs, we have investigated how these three components interact during nuclear assembly. We find that the Xenopus embryonic lamin protein LIII cannot bind directly to chromatin or membranes when each is present alone, but is readily incorporated into nuclei when both of the components are present together in an assembly extract. We find that depleting lamin LIII from an extract does not prevent formation of an envelope consisting of membranes and nuclear pores. However, these lamin-depleted envelopes are extremely fragile and fail to grow beyond a limited extent. This suggests that lamin assembly is not required during the initial steps of nuclear envelope formation, but is required for later growth and for maintaining the structural integrity of the envelope. We also present results showing that lamins may only be incorporated into nuclei after DNA has been encapsulated within an envelope and nuclear transport has been activated. With respect to nuclear function, our results show that the presence of a nuclear lamina is required for DNA synthesis to occur within assembled nuclei.

scholarly journals Chromosome length and gene density contribute to micronuclear membrane stability

2021 ◽  
Author(s):  
Anna Mammel ◽  
Heather Z Huang ◽  
Amanda L Gunn ◽  
Emma Choo ◽  
Emily M Hatch
Keyword(s):  
Nuclear Envelope ◽  
Membrane Integrity ◽  
Nuclear Lamina ◽  
Chromosome Length ◽  
Gene Density ◽  
Membrane Stability ◽  
Nuclear Pore ◽  
Membrane Rupture ◽  
Lamin B1 ◽  
Nuclear Envelope Assembly

Micronuclei are derived from missegregated chromosomes and frequently lose membrane integrity, leading to DNA damage, innate immune activation, and metastatic signaling. Here we demonstrate that two characteristics of the trapped chromosome, length and gene density, are key contributors to micronuclei membrane stability in human cells. Chromosome length is proportional to micronuclei size, and gene density has an additive effect with micronucleus size on membrane stability. We demonstrate that these results are not due to chromosome-specific differences in spindle position or initial nuclear pore complex recruitment during post-mitotic nuclear envelope assembly. We find that chromosome length and micronuclei size strongly correlate with lamin B1 and nuclear pore density in intact micronuclei. Unexpectedly, lamin B1 levels do not predict nuclear lamina organization and membrane stability. Instead, small gene-dense micronuclei have decreased nuclear lamina gaps compared to large micronuclei, despite very low levels of lamin B1. Our data strongly suggest that nuclear envelope composition defects previously correlated with membrane rupture only partly explain membrane stability in micronuclei. We propose that an unknown factor linked to gene density has a separate function that inhibits the appearance of nuclear lamina gaps and delays membrane rupture until late in the cell cycle.

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

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.

scholarly journals Chromosome length and gene density contribute to micronuclear membrane stability

2021 ◽  
Vol 5 (2) ◽  
pp. e202101210
Author(s):  
Anna E Mammel ◽  
Heather Z Huang ◽  
Amanda L Gunn ◽  
Emma Choo ◽  
Emily M Hatch
Keyword(s):  
Nuclear Envelope ◽  
Membrane Integrity ◽  
Nuclear Lamina ◽  
Chromosome Length ◽  
Gene Density ◽  
Membrane Stability ◽  
Nuclear Pore ◽  
Membrane Rupture ◽  
Lamin B1 ◽  
Nuclear Envelope Assembly

Micronuclei are derived from missegregated chromosomes and frequently lose membrane integrity, leading to DNA damage, innate immune activation, and metastatic signaling. Here, we demonstrate that two characteristics of the trapped chromosome, length and gene density, are key contributors to micronuclei membrane stability and determine the timing of micronucleus rupture. We demonstrate that these results are not due to chromosome-specific differences in spindle position or initial protein recruitment during post-mitotic nuclear envelope assembly. Micronucleus size strongly correlates with lamin B1 levels and nuclear pore density in intact micronuclei, but, unexpectedly, lamin B1 levels do not completely predict nuclear lamina organization or membrane stability. Instead, small gene-dense micronuclei have decreased nuclear lamina gaps compared to large micronuclei, despite very low levels of lamin B1. Our data strongly suggest that nuclear envelope composition defects previously correlated with membrane rupture only partly explain membrane stability in micronuclei. We propose that an unknown factor linked to gene density has a separate function that inhibits the appearance of nuclear lamina gaps and delays membrane rupture until late in the cell cycle.

scholarly journals Nuclear lamins and diabetes mellitus

STEMedicine ◽  
2020 ◽  
Vol 2 (5) ◽  
pp. e73
Author(s):  
Wei Xie ◽  
Brian Burke
Keyword(s):  
Diabetes Mellitus ◽  
Association Studies ◽  
Nuclear Lamina ◽  
Major Constituent ◽  
Genome Wide Association Studies ◽  
Intermediate Filament Proteins ◽  
Partial Lipodystrophy ◽  
Nuclear Lamins ◽  
Genes Encoding ◽  
Type V

In metazoans, a thin filamentous network referred to as the nuclear lamina plays an essential role in providing mechanical support to the nucleus. The major constituent of the nuclear lamina is type V intermediate filament proteins that are collectively referred to as lamins. A variety of diseases collectively termed laminopathies have been linked to mutations in genes encoding nuclear envelope proteins, in particular lamins, such as X-linked Emery Dreifus muscular dystrophy, dilated cardiomyopathy, Dunnigan type familial partial lipodystrophy and Hutchinson-Gilford progeria syndrome. Apart from laminopathies, genome-wide association studies have also been implicated nuclear lamins in the pathophysiology of type 2 diabetes mellitus, although little information in terms of the function of lamins in its pathogenesis. Our current review attempts to summarize risk factors of diabetes mellitus that could be attributable to lamin mutations and indirectly linked to lamin-associated factors identified in the last two decades.

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