Lamin proteins form an internal nucleoskeleton as well as a peripheral lamina in human cells

1995 ◽  
Vol 108 (2) ◽  
pp. 635-644 ◽  
Author(s):  
P. Hozak ◽  
A.M. Sasseville ◽  
Y. Raymond ◽  
P.R. Cook
Keyword(s):  
Nuclear Membrane ◽  
Intermediate Filament ◽  
Mammalian Cells ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Human Cells ◽  
Lamin A ◽  
Intermediate Filament Proteins ◽  
Form Part ◽  
Dense Chromatin

The nuclear lamina forms a protein mesh that underlies the nuclear membrane. In most mammalian cells it contains the intermediate filament proteins, lamins A, B and C. As their name indicates, lamins are generally thought to be confined to the nuclear periphery. We now show that they also form part of a diffuse skeleton that ramifies throughout the interior of the nucleus. Unlike their peripheral counterparts, these internal lamins are buried in dense chromatin and so are inaccessible to antibodies, but accessibility can be increased by removing chromatin. Knobs and nodes on an internal skeleton can then be immunolabelled using fluorescein- or gold-conjugated anti-lamin A antibodies. These results suggest that the lamins are misnamed as they are also found internally.

A new model for nuclear lamina organization

2008 ◽  
Vol 36 (6) ◽  
pp. 1339-1343 ◽  
Author(s):  
Martin W. Goldberg ◽  
Jindriska Fiserova ◽  
Irm Huttenlauch ◽  
Reimer Stick
Keyword(s):  
Mechanical Strength ◽  
Nuclear Membrane ◽  
Intermediate Filament ◽  
Xenopus Oocytes ◽  
Nuclear Lamina ◽  
Intermediate Filament Proteins ◽  
New Model ◽  
10 Nm Filaments

Lamins are intermediate filament proteins that form a network lining the inner nuclear membrane. They provide mechanical strength to the nuclear envelope, but also appear to have many other functions as reflected in the array of diseases caused by lamin mutations. Unlike other intermediate filament proteins, they do not self-assemble into 10 nm filaments in vitro and their in vivo organization is uncertain. We have recently re-examined the organization of a simple B-type lamina in Xenopus oocytes [Goldberg, Huttenlauch, Hutchison and Stick (2008) J. Cell Sci. 121, 215–225] and shown that it consists of tightly packed 8–10 nm filaments with regular cross-connections, tightly opposed to the membrane. When lamin A is expressed in oocytes, it forms organized bundles on top of the B lamina. This has led to a new model for lamina organization which is discussed in the present paper.

Monoclonal antibodies to plant nuclear matrix reveal intermediate filamentrelated components within the nucleus

1991 ◽  
Vol 98 (3) ◽  
pp. 293-302
Author(s):  
ALISON BEVEN ◽  
YUHONG GUAN ◽  
JAN PEART ◽  
CHRISTINE COOPER ◽  
PETER SHAW
Keyword(s):  
Monoclonal Antibodies ◽  
Nuclear Matrix ◽  
Intermediate Filament ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Protein S ◽  
Intermediate Filament Proteins ◽  
Daucus Carota L ◽  
Culture Cells ◽  
Matrix Fraction

We have prepared a nuclear matrix fraction from purified nuclei of carrot (Daucus carota L.) suspension culture cells, and used this fraction to produce a library of monoclonal antibodies. We report the preliminary characterisation of two antibodies-JIM 62 and JIM 63. The antibodies recognise a polypeptide doublet band at 92xl03Mr, which has been partially purified by differential urea extraction. Other intermediate filament antibodies-ME101, which recognises an epitope conserved among many intermediate filament proteins, and AFB, a monoclonal antibody to plant intermediate filament proteins, and an autoimmune serum directed against human lamina A and C (LSI), also label these bands, suggesting they are related to the intermediate filament/lamin family. IFA, another intermediate filament antibody, labels a band at approximately 60x103Mr, which is also enriched in the urea extracts of nuclear matrices. Immunofluorescence microscopy with JIM 63, ME 101, AFB and LSI shows network-like staining, often extending around the nucleolus. In many cases the staining reveals structures that appear to be bundles of fibres. JIM 63 also shows a weak staining of the nuclear rim in carrot nuclei, which can be greatly enhanced by treatment of the specimen with cold methanol after fixation. JIM 63 cross-reacts with all the other plant species we have tested. Vibratome sections of pea roots, extracted as for nuclear matrix preparation and stained with JIM 63 show a clear, strong nuclear rim labelling. Furthermore, JIM 63 strongly labels the nuclear lamina in rat liver nuclei. We suggest that the 92x103Mr protein(s) are related to intermediate filaments and/or lamins, and are distributed both within the nucleus and at the nuclear periphery.

scholarly journals Expression of nuclear lamins in mammalian somatic cells lacking cytoplasmic intermediate filament proteins

1989 ◽  
Vol 92 (3) ◽  
pp. 361-370 ◽  
Author(s):  
M. Paulin-Levasseur ◽  
A. Scherbarth ◽  
G. Giese ◽  
K. Roser ◽  
W. Bohn ◽  
...  
Keyword(s):  
Cell Lines ◽  
Phorbol Ester ◽  
Intermediate Filament ◽  
Mammalian Cells ◽  
Somatic Cells ◽  
Nuclear Lamina ◽  
Intermediate Filament Proteins ◽  
Inhibition Of Proliferation ◽  
Lamin B ◽  
Nuclear Lamins

Using immunofluorescence and immunoblotting techniques, we have examined the composition of the nuclear lamina in murine plasmacytoma cells, MPC-11, exposed to the phorbol ester TPA as well as in two cell lines devoid of cytoplasmic intermediate filament proteins, the human adrenal cortex carcinoma-derived cells SW-13 and the clone C6-M-D4 derived from the rat glial cell line C6. Our results show that the inhibition of proliferation and the induction of vimentin synthesis observed in TPA-treated MPC-11 populations are not paralleled by changes in the lamin complement of these cells, which contain lamin B but lack lamins A and C. Furthermore, the analysis performed on SW-13 and C6-M-D4 cell lines clearly demonstrates that mammalian somatic cells display considerable variations in lamin expression and indicates that lamin B may be the only lamin species constitutively expressed in mammalian cells.

scholarly journals Lamin C is required to establish genome organization after mitosis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xianrong Wong ◽  
Victoria E. Hoskins ◽  
Ashley J. Melendez-Perez ◽  
Jennifer C. Harr ◽  
Molly Gordon ◽  
...  
Keyword(s):  
Genome Organization ◽  
Mammalian Cells ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Lamin A ◽  
Chromosome Architecture ◽  
3D Genome ◽  
Mouse Cells ◽  
The Individual ◽  
Differential Phosphorylation

Abstract Background The dynamic 3D organization of the genome is central to gene regulation and development. The nuclear lamina influences genome organization through the tethering of lamina-associated domains (LADs) to the nuclear periphery. Evidence suggests that lamins A and C are the predominant lamins involved in the peripheral association of LADs, potentially serving different roles. Results Here, we examine chromosome architecture in mouse cells in which lamin A or lamin C are downregulated. We find that lamin C, and not lamin A, is required for the 3D organization of LADs and overall chromosome organization. Striking differences in localization are present as cells exit mitosis and persist through early G1 and are linked to differential phosphorylation. Whereas lamin A associates with the nascent nuclear envelope (NE) during telophase, lamin C remains in the interior, surrounding globular LAD aggregates enriched on euchromatic regions. Lamin C association with the NE is delayed until several hours into G1 and correlates temporally and spatially with the post-mitotic NE association of LADs. Post-mitotic LAD association with the NE, and global 3D genome organization, is perturbed only in cells depleted of lamin C, and not lamin A. Conclusions Lamin C regulates LAD dynamics during exit from mitosis and is a key regulator of genome organization in mammalian cells. This reveals an unexpectedly central role for lamin C in genome organization, including inter-chromosomal LAD-LAD segregation and LAD scaffolding at the NE, raising intriguing questions about the individual and overlapping roles of lamin A/C in cellular function and disease.

scholarly journals Lamin C regulates genome organization after mitosis

2020 ◽  
Author(s):  
X Wong ◽  
VE Hoskins ◽  
JC Harr ◽  
M Gordon ◽  
KL Reddy
Keyword(s):  
Genome Organization ◽  
Mammalian Cells ◽  
Regulation Of Gene Expression ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Lamin A ◽  
3D Genome ◽  
Cellular Processes ◽  
Genomic Regions ◽  
In Cells

AbstractThe dynamic 3D organization of the genome is central to the regulation of gene expression and developmental progression, with its disruption being implicated in various diseases. The nuclear lamina, a proteinaceous meshwork underlying the nuclear envelope (NE), provides both structural and regulatory influences on genome organization through the tethering of large inactive genomic regions, called Lamina Associated Domains (LADs), to the nuclear periphery. Evidence suggests that the A type lamins, lamins A and C, are the predominant lamins involved in the peripheral association of LADs, with these two isotypes forming distinct networks and potentially involved in different cellular processes. Here we tested whether lamins A and C have distinct roles in genome organization by examining chromosome architecture in cells in which lamin C or lamin A are specifically down-regulated. We find that lamin C (not lamin A) is required for the 3D organization of LADs and overall chromosome organization in the cell nucleus. Striking differences in the localization of lamin A and lamin C are present as cells exit mitosis that persist through early G1. Whereas lamin A associates with the nascent NE during telophase, lamin C remains in the interior surrounding nucleoplasmic LAD clusters. Lamin C association with the NE is delayed until several hours into G1 and correlates temporally and spatially with the post-mitotic NE association of LADs. Post-mitotic LAD association with the NE, and consequently global 3D genome organization, is perturbed only in cells depleted of lamin C, and not in cells depleted of lamin A. We conclude that lamin C regulates LAD dynamics after mitosis and is a key regulator of genome organization in mammalian cells. These findings reveal an unexpectedly central role for lamin C in genome organization, including both inter-chromosomal LAD-LAD segregation and LAD scaffolding at the NE.

Active microrheology using pulsed optical tweezers to probe viscoelasticity of Lamin A

Soft Matter ◽  
2021 ◽  
Author(s):  
Chandrayee Mukherjee ◽  
Avijit Kundu ◽  
Raunak Dey ◽  
Ayan Banerjee ◽  
Kaushik Sengupta
Keyword(s):  
Optical Tweezers ◽  
Intermediate Filament ◽  
Mammalian Cells ◽  
Lamin A ◽  
Intermediate Filament Proteins ◽  
Type V

Lamins are nucleoskeletal proteins of mammalian cells that stabilize the structure and maintain the rigidity of the nucleus. These type V intermediate filament proteins which are predominantly of A and...

scholarly journals Visualization of the Nuclear Lamina in Mouse Anterior Pituitary Cells and Immunocytochemical Detection of Lamin A/C by Quick-freeze Freeze-substitution Electron Microscopy

2005 ◽  
Vol 53 (4) ◽  
pp. 497-507 ◽  
Author(s):  
Takao Senda ◽  
Akiko Iizuka-Kogo ◽  
Atsushi Shimomura
Keyword(s):  
Electron Microscopy ◽  
Nuclear Membrane ◽  
Anterior Pituitary ◽  
Freeze Substitution ◽  
Nuclear Lamina ◽  
Immunogold Electron Microscopy ◽  
Lamin A ◽  
Pituitary Cells ◽  
Inner Nuclear Membrane ◽  
Anterior Pituitary Cells

We examined the nuclear lamina in the quickly frozen anterior pituitary cells by electron microscopic techniques combined with freeze substitution, deep etching, and immunocytochemistry and compared it with that in the chemically fixed cells. By quick-freeze freeze-substitution electron microscopy, an electron-lucent layer, as thick as 20 nm, was revealed just inside the inner nuclear membrane, whereas in the conventionally glutaraldehyde-fixed cells the layer was not seen. By quick-freeze deep-etch electron microscopy, we could not distinguish definitively the layer corresponding to the nuclear lamina in either fresh unfixed or glutaraldehyde-fixed cells. Immunofluorescence microscopy showed that lamin A/C in the nucleus was detected in the acetone-fixed cells and briefly in paraformaldehyde-fixed cells but not in the cells with prolonged paraformaldehyde fixation. Nuclear localization of lamin A/C was revealed by immunogold electron microscopy also in the quickly frozen and freeze-substituted cells, but not in the paraformaldehyde-fixed cells. Lamin A/C was localized mainly in the peripheral nucleoplasm within 60 nm from the inner nuclear membrane, which corresponded to the nuclear lamina. These results suggest that the nuclear lamina can be preserved both ultrastructurally and immunocytochemically by quick-freezing fixation, rather than by conventional chemical fixation.

scholarly journals Colocalization of intranuclear lamin foci with RNA splicing factors

1999 ◽  
Vol 112 (24) ◽  
pp. 4651-4661 ◽  
Author(s):  
G. Jagatheesan ◽  
S. Thanumalayan ◽  
B. Muralikrishna ◽  
N. Rangaraj ◽  
A.A. Karande ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Rna Splicing ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Splicing Factors ◽  
Lamin A ◽  
Lamin B1 ◽  
Differential Reactivity ◽  
Fibrous Network

The lamins form a fibrous network underlying the inner nuclear membrane termed the nuclear lamina. In order to gain insights into the role of lamins in nuclear organization, we have characterized a monoclonal antibody (LA-2H10) raised against recombinant rat lamin A that labels nuclei in a speckled pattern in all cells of unsynchronized populations of HeLa and rat F-111 fibroblast cells, unlike the typical nuclear periphery staining by another monoclonal antibody to lamin A, LA-2B3. In immunolocalization studies the lamin A speckles or foci were found to colocalize with the RNA splicing factors SC-35 and U5-116 kD, but not with p80 coilin found in coiled bodies. Lamin B1 was also associated with these foci. These foci dispersed when cells entered mitosis and reformed during anaphase. The differential reactivity of LA-2H10 and LA-2B3 was retained after nuclei were extracted with detergents, nucleases and salt to disrupt interactions of lamins with chromatin and other nuclear proteins. Using deletion fragments of recombinant lamin A, the epitope recognized by LA-2H10 was located between amino acids 171 and 246. Our findings are consistent with a structural role for lamins in supporting nuclear compartments containing proteins involved in RNA splicing.

Expression patterns of intermediate filament proteins desmin and lamin A in the developing conduction system of early human embryonic hearts

2019 ◽  
Vol 236 (3) ◽  
pp. 540-548
Author(s):  
Hui‐Xia Liu ◽  
Yi‐Xin Jing ◽  
Jing‐Jing Wang ◽  
Yan‐Ping Yang ◽  
Yun‐Xiu Wang ◽  
...  
Keyword(s):  
Intermediate Filament ◽  
Expression Patterns ◽  
Conduction System ◽  
Lamin A ◽  
Intermediate Filament Proteins ◽  
Early Human

scholarly journals Directed targeting of chromatin to the nuclear lamina is mediated by chromatin state and A-type lamins

2015 ◽  
Vol 208 (1) ◽  
pp. 33-52 ◽  
Author(s):  
Jennifer C. Harr ◽  
Teresa Romeo Luperchio ◽  
Xianrong Wong ◽  
Erez Cohen ◽  
Sarah J. Wheelan ◽  
...  
Keyword(s):  
Binding Sites ◽  
Nuclear Organization ◽  
Insertion Site ◽  
Nuclear Periphery ◽  
Histone H3 ◽  
Nuclear Lamina ◽  
Lamin A ◽  
Developmentally Regulated ◽  
Specific Variable ◽  
Endogenous Loci

Nuclear organization has been implicated in regulating gene activity. Recently, large developmentally regulated regions of the genome dynamically associated with the nuclear lamina have been identified. However, little is known about how these lamina-associated domains (LADs) are directed to the nuclear lamina. We use our tagged chromosomal insertion site system to identify small sequences from borders of fibroblast-specific variable LADs that are sufficient to target these ectopic sites to the nuclear periphery. We identify YY1 (Ying-Yang1) binding sites as enriched in relocating sequences. Knockdown of YY1 or lamin A/C, but not lamin A, led to a loss of lamina association. In addition, targeted recruitment of YY1 proteins facilitated ectopic LAD formation dependent on histone H3 lysine 27 trimethylation and histone H3 lysine di- and trimethylation. Our results also reveal that endogenous loci appear to be dependent on lamin A/C, YY1, H3K27me3, and H3K9me2/3 for maintenance of lamina-proximal positioning.

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