Cells of the cellular immune and hemopoietic system of the mouse lack lamins A/C: distinction versus other somatic cells

1990 ◽  
Vol 95 (4) ◽  
pp. 587-598
Author(s):  
R.A. Rober ◽  
H. Sauter ◽  
K. Weber ◽  
M. Osborn
Keyword(s):  
Adult Mouse ◽  
Somatic Cells ◽  
Nuclear Lamina ◽  
Lamin A ◽  
Monocytic Cells ◽  
Lamin B ◽  
Nuclear Lamins ◽  
Almost All ◽  
Cellular Immune ◽  
Hemopoietic System

Almost all somatic cells in adult murine tissues express all three nuclear lamins (A, B, C). Here we demonstrate that cells of the hemopoietic system of the adult mouse are an exception in that they express only lamin B. Thus T and B lymphocytes as well as granulocytes and monocytic cells directly isolated from spleen, thymus, blood or bone marrow do not express lamin A/C but only lamin B. In agreement with this observation the murine hemopoietic cell lines EL4, BW5147, HK22, 70Z/3, SP2/0 and PAI express only lamin B. In immunoblotting experiments used to confirm the immunofluorescence data no lamin A/C expression was detected. However, we noticed that murine lamin B occurs in two isoforms, which can be distinguished immunologically. These results reinforce the idea that a functional nuclear lamina can be formed from lamin B alone. They also pose the question of whether cells lacking lamin A/C are more plastic in their developmental programs than those that express all three lamins.

scholarly journals Lamin B constitutes an intermediate filament attachment site at the nuclear envelope.

1987 ◽  
Vol 105 (1) ◽  
pp. 117-125 ◽  
Author(s):  
S D Georgatos ◽  
G Blobel
Keyword(s):  
Plasma Membrane ◽  
Specific Binding ◽  
Attachment Site ◽  
Nuclear Lamina ◽  
Membrane Skeleton ◽  
Eukaryotic Cells ◽  
Lamin A ◽  
Lamin B ◽  
Nuclear Lamins

We found that urea extraction of turkey erythrocyte nuclear envelopes abolished their ability to bind exogenous 125I-vimentin, while, at the same time, it removed the nuclear lamins from the membranes. After purification of the lamins from such urea extracts, a specific binding between isolated vimentin and lamin B, or a lamin A + B hetero-oligomer, was detected by affinity chromatography. Similar analysis revealed that the 6.6-kD vimentin tail piece was involved in this interaction. By other approaches (quantitative immunoprecipitation, rate zonal sedimentation, turbidometric assays) a substoichiometric lamin B-vimentin binding was determined under in vitro conditions. It was also observed that anti-lamin B antibodies but not other sera (anti-lamin A, anti-ankyrin, preimmune) were able to block 70% of the binding of 125I-vimentin to native, vimentin-depleted, nuclear envelopes. These data, which were confirmed by using rat liver nuclear lamins, indicate that intermediate filaments may be anchored directly to the nuclear lamina, providing a continuous network connecting the plasma membrane skeleton with the karyoskeleton of eukaryotic cells.

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.

Expression of nuclear lamins during mouse preimplantation development

Development ◽  
1988 ◽  
Vol 102 (2) ◽  
pp. 271-278
Author(s):  
E. Houliston ◽  
M.N. Guilly ◽  
J.C. Courvalin ◽  
B. Maro
Keyword(s):  
Cell Differentiation ◽  
Early Development ◽  
Nuclear Periphery ◽  
Preimplantation Development ◽  
Lamin A ◽  
Positive Staining ◽  
Lamin B ◽  
Nuclear Lamins ◽  
Mouse Cells

The expression of nuclear lamins during mouse preimplantation development was studied by immunofluorescence, immunoblotting and immunoprecipitation. Two sera were used, specific either for lamin B or lamins A and C. Both sera gave a positive staining of the nuclear periphery throughout preimplantation development (fertilized eggs to late blastocysts). Immunoblots revealed that the three lamins were present in eggs and blastocysts. However, lamin A from eggs was found to have a higher apparent Mr than lamin A from blastocysts and other mouse cells. Using immunoprecipitation, synthesis of lamin A was detected in eggs while synthesis of lamin B was detected in 8-cell embryos and blastocysts, indicating that at least some of the lamins used during early development do not come from a store in the egg. These results are discussed in relation to the possible role of lamins during cell differentiation.

scholarly journals Gaussian curvature dilutes the nuclear lamina, favoring nuclear rupture, especially at high strain rate

2021 ◽  
Author(s):  
Charlotte R Pfeifer ◽  
Michael P Tobin ◽  
Sangkyun Cho ◽  
Manasvita Vashisth ◽  
Lawrence J Dooling ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Gaussian Curvature ◽  
Cell Imaging ◽  
High Strain ◽  
Nuclear Lamina ◽  
Lamin A ◽  
Strain Rates ◽  
Lamin B ◽  
Hypotonic Stress ◽  
Nuclear Rupture

Nuclear rupture has long been associated with deficits or defects in lamins, with recent results also indicating a role for actomyosin stress, but key physical determinants of rupture remain unclear. Here, lamin-B stably interacts with the nuclear membrane at sites of low Gaussian curvature yet dilutes at high-curvature to favor rupture, whereas lamin-A depletes similarly but only at high strain-rates. Live cell imaging of lamin-B1 gene-edited cancer cells is complemented by fixed-cell imaging of ruptured nuclei in: iPS-derived cells from progeria patients, cells within beating chick embryo hearts, and cancer cells that develop multiple ruptures in migrating through small pores. Dilution and curvature-dependent rupture fit a parsimonious model of a stiff filament that detaches from a curved surface, suggesting an elastic-type response of lamin-B, but rupture is also modestly suppressed by inhibiting myosin-II and by hypotonic stress, which slow the strain rates. Lamin-A dilution and nuclear rupture likelihood indeed increase above a threshold rate of pulling into small pipettes, suggesting a viscoplastic coupling to the envelope for protection against nuclear rupture.

The role of sequences unique to nuclear intermediate filaments in the targeting and assembly of human lamin B: evidence for lack of interaction of lamin B with its putative receptor

1998 ◽  
Vol 111 (23) ◽  
pp. 3471-3485 ◽  
Author(s):  
T.I. Mical ◽  
M.J. Monteiro
Keyword(s):  
Mammalian Cells ◽  
Nuclear Lamina ◽  
Lamin B ◽  
Nuclear Lamins ◽  
Putative Receptor ◽  
Lamin B Receptor ◽  
Nuclear Lamin ◽  
Efficient Integration ◽  
Caax Motif

The mechanism by which human nuclear lamin B is targeted and assembled has been studied by transfecting into mammalian cells lamin mutants deleted of three sequences unique to lamins. Nuclear lamins contain an extra 42 amino acids (aa) in their rod domains and NLS and CAAX motifs in their tail domains, which distinguishes them from cytoplasmic IF proteins. These three sequences act in concert to ensure correct temporal and spatial assembly of lamin B. Deletion of any one of these three sequences from lamin B did not significantly disrupt nuclear lamina targeting, but when two or more of these sequences were deleted, targeting was severely compromised. The CAAX motif is necessary for the efficient integration of lamin B into an already formed nuclear lamina, since lamin B CAAX- mutants had reduced targeting to the lamina when arrested in S phase of the cell cycle. CAAX-deficient mutant lamin B proteins were soluble and not associated with membranes at mitosis, proving that the CAAX motif is responsible for association of human lamin B with membranes. In addition, CAAX- mutant lamin B proteins fractionated independently of the lamin B-receptor (LBR), indicating that these two proteins do not bind directly to each other.

Dynamics of the nuclear lamina as monitored by GFP-tagged A-type lamins

1999 ◽  
Vol 112 (20) ◽  
pp. 3463-3475 ◽  
Author(s):  
J.L. Broers ◽  
B.M. Machiels ◽  
G.J. van Eys ◽  
H.J. Kuijpers ◽  
E.M. Manders ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Nuclear Lamina ◽  
Time Lapse ◽  
Lamin A ◽  
Tubular Structures ◽  
Vertical Orientation ◽  
Nuclear Lamins ◽  
Low Protein ◽  
Orientation Time ◽  
Green Fluorescent

The behavior of chimeric proteins consisting of A-type lamins and green fluorescent protein (GFP) was studied to investigate the localization and dynamics of nuclear lamins in living cells. Cell line CHO-K1 was transfected with cDNA constructs encoding fusion proteins of lamin A-GFP, lamin Adelta10-GFP, or lamin C-GFP. In the interphase nucleus lamin-GFP fluorescence showed a perinuclear localization and incorporation into the lamina for all three constructs. Our findings show for the first time that the newly discovered lamin A 10 protein is localized to the nuclear membrane. The GFP-tagged lamins were processed and behaved similarly to the endogenous lamin molecules, at least in cells that expressed physiological levels of the GFP-lamins. In addition to the typical perinuclear localization, in the majority of transfected cells each individual A-type lamin-GFP revealed an extensive collection of branching intra- and trans-nuclear tubular structures, which showed a clear preference for a vertical orientation. Time-lapse studies of 3-D reconstructed interphase cells showed a remarkable stability in both number and location of these structures over time, while the lamina showed considerable dynamic movements, consisting of folding and indentation of large parts of the lamina. Fluorescence recovery after bleaching studies revealed a low protein turnover of both tubular and lamina-associated lamins. Repetitive bleaching of intranuclear areas revealed the presence of an insoluble intranuclear fraction of A-type lamins. Time-lapse studies of mitotic cells showed that reformation of the lamina and the tubular structures consisting of A-type lamins did not occur until after cytokinesis was completed.

Nuclear and chromatin composition of mammalian gametes and early embryos

1992 ◽  
Vol 70 (10-11) ◽  
pp. 856-866 ◽  
Author(s):  
Hugh J. Clarke
Keyword(s):  
Topoisomerase Ii ◽  
Somatic Cells ◽  
Nuclear Lamina ◽  
Cell Types ◽  
Histone H1 ◽  
Lamin A ◽  
Dna Topoisomerase Ii ◽  
Cell Stage ◽  
Dna Topoisomerase ◽  
Mammalian Embryogenesis

Changes in nuclear structure and chromatin composition regulate gene activity in many cell types and could play a similar role during early mammalian embryogenesis. Oocytes of the mouse contain the three major lamin species present in somatic cells, although lamin A synthesized by oocytes has a higher molecular mass than the somatic species. Oocyte chromatin contains core histones similar to those of somatic cells, as well as elements that are immunologically related to protamines. In contrast, somatic-type histone H1 is not present. DNA topoisomerase II has not yet been identified in mammalian oocytes, but is abundant in frog oocytes. In contrast to oocytes, sperm do not contain a typical nuclear lamina. DNA topoisomerase II is detectable until late spermiogenesis. Although the DNA of sperm is associated mainly with protamines, some histone may be retained. There is also evidence that the arrangement of the DNA in the nucleus is nonrandom. These results demonstrate differences in nuclear and chromatin composition between oocytes and sperm. After fertilization, the nuclei of cleavage-stage blastomeres undergo programmed modifications. Lamin B is synthesized, whereas lamin A is not. In addition, a set of nuclear proteins is transiently synthesized in mice at the two-cell stage. Changes in embryonic chromatin composition also occur. The relative abundance of transcripts from different core histone genes differs between mouse oocytes and blastocysts. Furthermore, somatic histone H1 becomes detectable beginning at the mid-four-cell stage. As well, during early cleavage stages, expression of plasmid-borne genes becomes dependent on enhancers. Thus, developmentally regulated changes in nuclear and chromatin composition occur during early mammalian embryogenesis, and these may be important for the initiation and regulation of embryonic gene activity.Key words: chromatin, nucleus, embryogenesis, gametogenesis, mammals.

Abstract 508: Nuclear Lamins At Enhancers: A New Hypothesis for Laminopathies

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Kohta Ikegami ◽  
Stefano Secchia ◽  
Omar Almakki ◽  
Alexis V Stutzman ◽  
Sachie Ikegami ◽  
...  
Keyword(s):  
Gene Expression ◽  
Histone Acetylation ◽  
Binding Sites ◽  
Nuclear Periphery ◽  
Nuclear Lamina ◽  
Lamin A ◽  
New Paradigm ◽  
Control Of Gene Expression ◽  
Nuclear Lamins ◽  
Nuclear Interior

The segregation of heterochromatin domains (LADs) at the nuclear periphery by the nuclear lamina, composed by polymerized nuclear Lamin A/C, provides a longstanding paradigm for the control of gene expression and for the mechanisms underlying Lamin-A/C-associated disorders, including progeria and cardiomyopathy. Here, we provide evidence supporting a novel paradigm that Lamin A/C functions as a transcription factor in the nuclear interior. We discovered that Ser22-phosphorylated Lamin A/C (pS22-Lamin A/C), required for lamin depolymerization during mitosis, populated the nuclear interior throughout the cell cycle. pS22-Lamin A/C ChIP-deq demonstrated localization at a large subset of putative active enhancers, not LADs. pS22-Lamin A/C-binding sites were co-occupied by the transcriptional activator c-Jun. In progeria patient-derived fibroblasts, a subset of pS22-Lamin A/C-binding sites were lost whereas new pS22-Lamin A/C-binding sites emerged. New pS22-Lamin A/C binding was accompanied by increased histone acetylation and increased c-Jun binding, whereas loss of pS22-Lamin A/C-binding was accompanied by loss of histone acetylation and c-Jun binding. New pS22-Lamin A/C enhancer binding in progeria was associated with upregulated expression of genes implicated in progeria pathophysiology, including cardiovascular disease. In contrast, alteration of LADs in progeria-patient cells could not explain the observed gene expression changes. These results suggest that Lamin A/C regulates gene expression by enhancer binding in the nuclear interior, independent of its function at the nuclear lamina, providing a new paradigm for the pathogenesis of lamin-associated disorders. pS22-Lamin A/C was also present in the nuclear interior of adult mouse cardiomyocytes. Cardiomyocyte-specific deletion of Lmna encoding Lamin A/C in adult mice caused extensive transcriptional changes in the heart and dilated cardiomyopathy, without apparent reduction of nuclear peripheral Lamin A/C. Disruption of the gene regulatory rather than LAD tethering function of Lamin A/C may underlie the pathogenesis of disorders caused by LMNA mutations, including cardiomyopathy.

scholarly journals Dynamic properties of nuclear lamins: lamin B is associated with sites of DNA replication.

1994 ◽  
Vol 125 (6) ◽  
pp. 1201-1212 ◽  
Author(s):  
R D Moir ◽  
M Montag-Lowy ◽  
R D Goldman
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Dynamic Properties ◽  
Nuclear Lamina ◽  
S Phase ◽  
Nuclear Antigen ◽  
Nuclear Staining ◽  
Lamin B ◽  
Nuclear Lamins ◽  
Proliferating Cell

The nuclear lamins form a fibrous structure, the nuclear lamina, at the periphery of the nucleus. Recent results suggest that lamins are also present as foci or spots in the nucleoplasm at various times during interphase of the cell cycle (Goldman, A. E., R. D. Moir, M. Montag-Lowy, M. Stewart, and R. D. Goldman. 1992. J. Cell Biol. 104:725-732; Bridger, J. M., I. R. Kill, M. O'Farrell, and C. J. Hutchison. 1993. J. Cell Sci. 104:297-306). In this report we demonstrate that during mid-late S-phase, nuclear foci detected with lamin B antibodies are coincident with sites of DNA replication as detected by the colocalization of sites of incorporation of bromodeoxyuridine (BrDU) or proliferating cell nuclear antigen (PCNA). The relationship between lamin B and BrDU is not maintained in the following G1 stage of the cell cycle. Furthermore, the nuclear staining patterns seen with antibodies directed against lamins A and C in mid-late S-phase do not coalign with the lamin B/BrDU-containing structures. These results imply that there is a role for lamin B in the organization of replicating chromatin during S phase.

scholarly journals Chromatin compartment dynamics in a haploinsufficient model of cardiac laminopathy

2019 ◽  
Vol 218 (9) ◽  
pp. 2919-2944 ◽  
Author(s):  
Alessandro Bertero ◽  
Paul A. Fields ◽  
Alec S.T. Smith ◽  
Andrea Leonard ◽  
Kevin Beussman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Induced Pluripotent Stem Cell ◽  
Nuclear Lamina ◽  
Lamin A ◽  
Chromosome Conformation ◽  
Nuclear Lamins ◽  
Genome Wide ◽  
Induced Pluripotent ◽  
Gene Expression Alterations

Mutations in A-type nuclear lamins cause dilated cardiomyopathy, which is postulated to result from dysregulated gene expression due to changes in chromatin organization into active and inactive compartments. To test this, we performed genome-wide chromosome conformation analyses in human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) with a haploinsufficient mutation for lamin A/C. Compared with gene-corrected cells, mutant hiPSC-CMs have marked electrophysiological and contractile alterations, with modest gene expression changes. While large-scale changes in chromosomal topology are evident, differences in chromatin compartmentalization are limited to a few hotspots that escape segregation to the nuclear lamina and inactivation during cardiogenesis. These regions exhibit up-regulation of multiple noncardiac genes including CACNA1A, encoding for neuronal P/Q-type calcium channels. Pharmacological inhibition of the resulting current partially mitigates the electrical alterations. However, chromatin compartment changes do not explain most gene expression alterations in mutant hiPSC-CMs. Thus, global errors in chromosomal compartmentation are not the primary pathogenic mechanism in heart failure due to lamin A/C haploinsufficiency.

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