Expression of Lamin A Mutated in the Carboxyl-Terminal Tail Generates an Aberrant Nuclear Phenotype Similar to That Observed in Cells from Patients with Dunnigan-Type Partial Lipodystrophy and Emery-Dreifuss Muscular Dystrophy

Favreau, Catherine; Dubosclard, Emmanuelle; Östlund, Cecilia; Vigouroux, Corinne; Capeau, Jacqueline; Wehnert, Manfred; Higuet, Dominique; Worman, Howard J.; Courvalin, Jean-Claude; Buendia, Brigitte

doi:10.1006/excr.2002.5669

Cited by 96 publications

(85 citation statements)

References 37 publications

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“…Several studies have already shown that most A-type lamin mutations result in nuclear abnormalities, including frequent blebbing or dherniationsT, large-scale alterations in nuclear shape, increased separation of the inner and outer nuclear membranes, clustering of nuclear pores, loss of some inner nuclear membrane proteins from one pole of the nucleus, and disruption of the underlying electron-dense heterochromatin. These abnormalities can be observed in cells lacking A-type lamins [13,14,41], in cells from patients with A-type lamin mutations [17,42], and in cells transfected with A-type lamin mutants [15,23,24,43]. However, the extent of these alterations seems to be highly variable, especially in cultured cells, in which A-type lamincontaining cells are transfected with mutant forms of Atype lamin constructs.…”

Section: Discussionmentioning

confidence: 99%

“…The R386K mutation is in the rod domain of lamin A/C, while the other two mutations are localized in its tail domain [22]. While the effects of several of these mutations on lamina organization were already studied previously [15][16][17]23,24], these studies did not examine the effect on internally localized lamins. Moreover, this is the first study that examines the feasibility of FLIP to study organization of lamins at the molecular level.…”

Section: Introductionmentioning

confidence: 99%

“…In order to avoid artefacts due to transfection and overexpression, we chose to examine exclusively cell lines stably transfected with GFP-tagged mutant A-type lamins, with GFP-lamin expression levels similar to native A-type lamins. The use of the boldQ temperature-sensitive GFP vector ps65T-C1, permitting a controlled expression of lamin-GFP during only a limited period of time [25], can avoid the occurrence of structural nuclear abnormalities as seen in cells transfected with lamin-EGFP [23].…”

Section: Introductionmentioning

confidence: 99%

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Both lamin A and lamin C mutations cause lamina instability as well as loss of internal nuclear lamin organization

Broers

Kuijpers

Östlund

et al. 2005

Experimental Cell Research

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We have applied the fluorescence loss of intensity after photobleaching (FLIP) technique to study the molecular dynamics and organization of nuclear lamin proteins in cell lines stably transfected with green fluorescent protein (GFP)-tagged A-type lamin cDNA. Normal lamin A and C proteins show abundant decoration of the inner layer of the nuclear membrane, the nuclear lamina, and a generally diffuse localization in the nuclear interior. Bleaching studies revealed that, while the GFP-tagged lamins in the lamina were virtually immobile, the intranuclear fraction of these molecules was partially mobile. Intranuclear lamin C was significantly more mobile than intranuclear lamina A.In search of a structural cause for the variety of inherited diseases caused by A-type lamin mutations, we have studied the molecular organization of GFP-tagged lamin A and lamin C mutants R453W and R386K, found in Emery-Dreifuss muscular dystrophy (EDMD), and lamin A and lamin C mutant R482W, found in patients with Dunnigan-type familial partial lipodystrophy (FPLD). In all mutants, a prominent increase in lamin mobility was observed, indicating loss of structural stability of lamin polymers, both at the perinuclear lamina and in the intranuclear lamin organization. While the lamin rod domain mutant showed overall increased mobility, the tail domain mutants showed mainly intranuclear destabilization, possibly as a result of loss of interaction with chromatin. Decreased stability of lamin mutant polymers was confirmed by flow cytometric analyses and immunoblotting of nuclear extracts.Our findings suggest a loss of function of A-type lamin mutant proteins in the organization of intranuclear chromatin and predict the loss of gene regulatory function in laminopathies.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Both lamin A and lamin C mutations cause lamina instability as well as loss of internal nuclear lamin organization

Broers

Kuijpers

Östlund

et al. 2005

Experimental Cell Research

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“…The nuclei of hMOF depleted cells forms multiple lobules or indentations as visualized by immunofluorescence microscopy of DAPI stained cells (Taipale et al, 2005). Examples of such a polylobulated phenotype have previously been shown to occur in the laminopathy class of diseases (Liu et al, 2000;Favreau et al, 2003;Goldman et al, 2004). Changes in the composition of the nuclear lamins, proteins that help form the framework needed for nuclear membrane shape and stability, are recently emerging as a common event in many aspects of cancer development (Prokocimer et al, 2006).…”

Section: A Link With Cancermentioning

confidence: 99%

Males absent on the first (MOF): from flies to humans

2007

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Histone modifications such as acetylation, methylation and phosphorylation have been implicated in fundamental cellular processes such as epigenetic regulation of gene expression, organization of chromatin structure, chromosome segregation, DNA replication and DNA repair. Males absent on the first (MOF) is responsible for acetylating histone H4 at lysine 16 (H4K16) and is a key component of the MSL complex required for dosage compensation in Drosophila. The human ortholog of MOF (hMOF) has the same substrate specificity and recent purification of the human and Drosophila MOF complexes showed that these complexes were also highly conserved through evolution. Several studies have shown that loss of hMOF in mammalian cells leads to a number of different phenotypes; a G 2 /M cell cycle arrest, nuclear morphological defects, spontaneous chromosomal aberrations, reduced transcription of certain genes and an impaired DNA repair response upon ionizing irradiation. Moreover, hMOF is involved in ATM activation in response to DNA damage and acetylation of p53 by hMOF influences the cell's decision to undergo apoptosis instead of a cell cycle arrest. These data, highlighting hMOF as an important component of many cellular processes, as well as links between hMOF and cancer will be discussed.

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“…For example, their nuclei are frequently abnormally shaped. This shape change is accompanied by alterations in the distribution of nuclear pores, lamin B, nuclear membrane components, and heterochromatin (26)(27)(28)(29). Many of these changes are replicated when human cells are transfected with LMNA cDNAs carrying known mutations (27)(28)(29)(30)(31).…”

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confidence: 99%

Functions and dysfunctions of the nuclear lamin Ig-fold domain in nuclear assembly, growth, and Emery–Dreifuss muscular dystrophy

Shumaker

Lopez‐Soler²,

Adam

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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The non-␣-helical C terminus of Xenopus lamin B3 (LB3T) inhibits the polymerization of lamin B3 in vitro and prevents the assembly of nuclei in Xenopus egg interphase extracts. To more precisely define the functions of LB3T in nuclear assembly, we have expressed subdomains of LB3T and determined their effects on nuclear assembly in Xenopus extracts. The results demonstrate that the Ig-fold motif (LB3T-Ig) is sufficient to inhibit lamin polymerization in vitro. Addition of the LB3T-Ig to egg extracts before the introduction of chromatin prevents chromatin decondensation and the assembly of the lamina, membranes, and pore complexes comprising the nuclear envelope. When added to assembled nuclei, LB3T-Ig prevents the further incorporation of lamin B3 into the endogenous lamina and blocks nuclear growth. The introduction of a point mutation in LB3T-Ig (R454W; LB3T-IgRW), known to cause Emery-Dreifuss muscular dystrophy when present in lamin A, does not inhibit lamin polymerization, chromatin decondensation, or nuclear assembly and growth. These results shed light on the specific alterations in lamin functions attributable to a known muscular dystrophy mutation and provide an experimental framework for revealing the effects of other mutations causing a wide range of laminopathies. ''tail'' domains (3, 4). The crystal structures of three small regions within these domains are known. These structures include coils 1A and 2B of the central rod (5) and the Ig-like fold (Ig-fold) present in the tail (6, 7). The ␣-helical rod domain is required for the formation of coiled-coil lamin dimers, which are the building blocks of higher order lamin structures. The function(s) of the Ig-fold in the nuclear lamins is unknown. In other systems, however, this motif is involved in protein-protein, protein-DNA, and protein-phospholipid interactions (6).Within nuclei, lamins are found throughout the nucleoplasm and are concentrated in the lamina, which forms an interface between the inner nuclear membrane and chromatin (8,9). During the cell cycle, the organization of lamins in interphase nuclei is not static. For example, during S-phase, lamins associate with replication factors such as proliferating cell nuclear antigen and replication factor C (10-12), whereas in mitosis, lamins are phosphorylated by the mitotic kinase cdk1 (13), causing their disassembly during nuclear envelope breakdown (14 -16). Lamins are subsequently dephosphorylated as they repolymerize around chromatin during nuclear assembly in daughter cells (17,18). The process of lamin polymerization is initiated in the anaphase-telophase transition during which B-type lamins begin to assemble on chromosomes and continues into early G 1 (9).Insights into lamin functions have been obtained from studies of the cell-free assembly of nuclei in Xenopus egg interphase extracts (19). For example, addition of the non-␣-helical Cterminal domain of Xenopus lamin B3 (LB3T) inhibits lamin polymerization, chromatin decondensation, and nuclear membrane and pore assembly (20). Other lam...

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Expression of Lamin A Mutated in the Carboxyl-Terminal Tail Generates an Aberrant Nuclear Phenotype Similar to That Observed in Cells from Patients with Dunnigan-Type Partial Lipodystrophy and Emery-Dreifuss Muscular Dystrophy

Cited by 96 publications

References 37 publications

Both lamin A and lamin C mutations cause lamina instability as well as loss of internal nuclear lamin organization

Both lamin A and lamin C mutations cause lamina instability as well as loss of internal nuclear lamin organization

Males absent on the first (MOF): from flies to humans

Functions and dysfunctions of the nuclear lamin Ig-fold domain in nuclear assembly, growth, and Emery–Dreifuss muscular dystrophy

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