scholarly journals Deformation of the nucleus by TGFβ1 via the remodeling of nuclear envelope and histone isoforms

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Ya-Hui Chi ◽  
Wan-Ping Wang ◽  
Ming-Chun Hung ◽  
Gunn-Guang Liou ◽  
Jing-Ya Wang ◽  
...  

AbstractThe cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFβ1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFβ1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, clustering at the nuclear periphery and reintegrating into the nucleoplasm. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFβ1-induced compositional changes in the chromatin and nuclear lamina.

2021 ◽  
Author(s):  
Ya-Hui Chi ◽  
Wan-Ping Wang ◽  
Ming-Chun Hung ◽  
Gunn-Guang Liou ◽  
Jing-Ya Wang ◽  
...  

Abstract The cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFβ1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFβ1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed with no observable indications of DNA damage response. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, shuttling between the nucleus and cytoplasm, and clustering at the nuclear periphery. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFβ1-induced compositional changes in the chromatin and nuclear lamina.


2021 ◽  
Author(s):  
Ya-Hui Chi ◽  
Wan-Ping Wang ◽  
Ming-Chun Hung ◽  
Gunn-Guang Liou ◽  
Jing-Ya Wang ◽  
...  

Abstract The cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFb1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFb1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed with no observable indications of DNA damage response. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, shuttling between the nucleus and cytoplasm, and clustering at the nuclear periphery. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFb1-induced compositional changes in the chromatin and nuclear lamina.


2021 ◽  
Author(s):  
Ya-Hui Chi ◽  
Wan-Ping Wang ◽  
Ming-Chun Hung ◽  
Gunn-Guang Liou ◽  
Jing-Ya Wang ◽  
...  

Abstract The cause of nuclear shape abnormalities which are often seen in pre-neoplastic and malignant tissues is not clear. In this study we report that deformation of the nucleus can be induced by TGFb1 stimulation in several cell lines including Huh7. In our results, the upregulated histone H3.3 expression downstream of SMAD signaling contributed to TGFb1-induced nuclear deformation, a process of which requires incorporation of the nuclear envelope (NE) proteins lamin B1 and SUN1. During this process, the NE constitutively ruptured and reformed with no observable indications of DNA damage response. Contrast to lamin B1 which was relatively stationary around the nucleus, the upregulated lamin A was highly mobile, shuttling between the nucleus and cytoplasm, and clustering at the nuclear periphery. The chromatin regions that lost NE coverage formed a supra-nucleosomal structure characterized by elevated histone H3K27me3 and histone H1, the formation of which depended on the presence of lamin A. These results provide evidence that shape of the nucleus can be modulated through TGFb1-induced compositional changes in the chromatin and nuclear lamina.


1999 ◽  
Vol 112 (24) ◽  
pp. 4651-4661 ◽  
Author(s):  
G. Jagatheesan ◽  
S. Thanumalayan ◽  
B. Muralikrishna ◽  
N. Rangaraj ◽  
A.A. Karande ◽  
...  

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.


2001 ◽  
Vol 114 (14) ◽  
pp. 2577-2590 ◽  
Author(s):  
O. Anthony Vaughan ◽  
Mauricio Alvarez-Reyes ◽  
Joanna M. Bridger ◽  
Jos L. V. Broers ◽  
Frans C. S. Ramaekers ◽  
...  

Physical interactions between lamins and emerin were investigated by co-immunoprecipitation of in vitro translated proteins. Emerin interacted with in vitro translated lamins A, B1 and C in co-immunprecipitation reactions. Competition reactions revealed a clear preference for interactions between emerin and lamin C. Structural associations between lamins and emerin were investigated in four human cell lines displaying abnormal expression and/or localisation of lamins A and C. In each cell line absence of lamins A and C from the nuclear envelope (NE) was correlated with mis-localisation of endogenous and exogenous emerin to the ER. In two cell lines that did not express lamin A but did express lamin C, lamin C as well as emerin was mis-localised. When GFP-lamin A was expressed in SW13 cells (which normally express only very low levels of endogenous lamin A and mis-localise endogenous emerin and lamin C), all three proteins became associated with the NE. When GFP-lamin C was expressed in SW13 cells neither the endogenous nor the exogenous lamin C was localised to the NE and emerin remained in the ER. Finally, lamins A and C were selectively eliminated from the NE of HeLa cells using a dominant negative mutant of lamin B1. Elimination of these lamins from the lamina led to the accumulation of emerin as aggregates within the ER. Our data suggest that lamin A is essential for anchorage of emerin to the inner nuclear membrane and of lamin C to the lamina.


1998 ◽  
Vol 111 (15) ◽  
pp. 2227-2234 ◽  
Author(s):  
M. Alsheimer ◽  
E. Fecher ◽  
R. Benavente

Lamina-associated polypeptide 2 (LAP2) and the thymopoietins (TPs) are a family of proteins described in somatic cells of mammals, which are derived by alternative splicing from a single gene. For one of the members of the family (LAP2 = TPbeta) it has been shown that this integral membrane protein locates to the inner membrane of the nuclear envelope, and that it binds to chromatin and B-type lamins. In the present study, we observed that during the third phase of spermatogenesis (i.e. spermiogenesis), TP-labelling shifted progressively to one half of the nuclear periphery in round spermatids. In the elongating spermatid the signal then becomes restricted to one spot located at the posterior (centriolar) pole of the nucleus. Changes in localization are accompanied by the disappearance, first of TPgamma, and later on of LAP2/TPbeta. TPalpha is the only member of the family detectable in the mature sperm. Concomitantly, lamin B1, the only nuclear lamina protein known to be expressed in mammalian spermatids, showed a similar behaviour, i.e. shifted progressively to the centriolar pole of spermatid nuclei before it became undetectable in fully differentiated mature sperms. These results are the first demonstration that expression and localization patterns of TPs are coordinately and differentially regulated with lamins during a differentiation process.


2021 ◽  
Author(s):  
Laura A Murray-Nerger ◽  
Joshua L Justice ◽  
Pranav Rekapalli ◽  
Josiah E Hutton ◽  
Ileana M Cristea

Abstract The integrity and regulation of the nuclear lamina is essential for nuclear organization and chromatin stability, with its dysregulation being linked to laminopathy diseases and cancer. Although numerous posttranslational modifications have been identified on lamins, few have been ascribed a regulatory function. Here, we establish that lamin B1 (LMNB1) acetylation at K134 is a molecular toggle that controls nuclear periphery stability, cell cycle progression, and DNA repair. LMNB1 acetylation prevents lamina disruption during herpesvirus type 1 (HSV-1) infection, thereby inhibiting virus production. We also demonstrate the broad impact of this site on laminar processes in uninfected cells. LMNB1 acetylation negatively regulates canonical nonhomologous end joining by impairing the recruitment of 53BP1 to damaged DNA. This defect causes a delay in DNA damage resolution and a persistent activation of the G1/S checkpoint. Altogether, we reveal LMNB1 acetylation as a mechanism for controlling DNA repair pathway choice and stabilizing the nuclear periphery.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yasunao Kamikawa ◽  
Atsushi Saito ◽  
Koji Matsuhisa ◽  
Masayuki Kaneko ◽  
Rie Asada ◽  
...  

AbstractThe nuclear envelope (NE) safeguards the genome and is pivotal for regulating genome activity as the structural scaffold of higher-order chromatin organization. NE had been thought as the stable during the interphase of cell cycle. However, recent studies have revealed that the NE can be damaged by various stresses such as mechanical stress and cellular senescence. These types of stresses are called NE stress. It has been proposed that NE stress is closely related to cellular dysfunctions such as genome instability and cell death. Here, we found that an endoplasmic reticulum (ER)-resident transmembrane transcription factor, OASIS, accumulates at damaged NE. Notably, the major components of nuclear lamina, Lamin proteins were depleted at the NE where OASIS accumulates. We previously demonstrated that OASIS is cleaved at the membrane domain in response to ER stress. In contrast, OASIS accumulates as the full-length form to damaged NE in response to NE stress. The accumulation to damaged NE is specific for OASIS among OASIS family members. Intriguingly, OASIS colocalizes with the components of linker of nucleoskeleton and cytoskeleton complexes, SUN2 and Nesprin-2 at the damaged NE. OASIS partially colocalizes with BAF, LEM domain proteins, and a component of ESCRT III, which are involved in the repair of ruptured NE. Furthermore, OASIS suppresses DNA damage induced by NE stress and restores nuclear deformation under NE stress conditions. Our findings reveal a novel NE stress response pathway mediated by OASIS.


2014 ◽  
Vol 25 (8) ◽  
pp. 1287-1297 ◽  
Author(s):  
Yuxuan Guo ◽  
Youngjo Kim ◽  
Takeshi Shimi ◽  
Robert D. Goldman ◽  
Yixian Zheng

The nuclear lamina (NL) consists of lamin polymers and proteins that bind to the polymers. Disruption of NL proteins such as lamin and emerin leads to developmental defects and human diseases. However, the expression of multiple lamins, including lamin-A/C, lamin-B1, and lamin-B2, in mammals has made it difficult to study the assembly and function of the NL. Consequently, it has been unclear whether different lamins depend on one another for proper NL assembly and which NL functions are shared by all lamins or are specific to one lamin. Using mouse cells deleted of all or different combinations of lamins, we demonstrate that the assembly of each lamin into the NL depends primarily on the lamin concentration present in the nucleus. When expressed at sufficiently high levels, each lamin alone can assemble into an evenly organized NL, which is in turn sufficient to ensure the even distribution of the nuclear pore complexes. By contrast, only lamin-A can ensure the localization of emerin within the NL. Thus, when investigating the role of the NL in development and disease, it is critical to determine the protein levels of relevant lamins and the intricate shared or specific lamin functions in the tissue of interest.


2019 ◽  
Vol 28 (23) ◽  
pp. 3982-3996 ◽  
Author(s):  
Vered Shani ◽  
Hazem Safory ◽  
Raymonde Szargel ◽  
Ninghan Wang ◽  
Tsipora Cohen ◽  
...  

Abstract Mutations in LRRK2 cause autosomal dominant and sporadic Parkinson’s disease, but the mechanisms involved in LRRK2 toxicity in PD are yet to be fully understood. We found that LRRK2 translocates to the nucleus by binding to seven in absentia homolog (SIAH-1), and in the nucleus it directly interacts with lamin A/C, independent of its kinase activity. LRRK2 knockdown caused nuclear lamina abnormalities and nuclear disruption. LRRK2 disease mutations mostly abolish the interaction with lamin A/C and, similar to LRRK2 knockdown, cause disorganization of lamin A/C and leakage of nuclear proteins. Dopaminergic neurons of LRRK2 G2019S transgenic and LRRK2 −/− mice display decreased circularity of the nuclear lamina and leakage of the nuclear protein 53BP1 to the cytosol. Dopaminergic nigral and cortical neurons of both LRRK2 G2019S and idiopathic PD patients exhibit abnormalities of the nuclear lamina. Our data indicate that LRRK2 plays an essential role in maintaining nuclear envelope integrity. Disruption of this function by disease mutations suggests a novel phosphorylation-independent loss-of-function mechanism that may synergize with other neurotoxic effects caused by LRRK2 mutations.


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