Nuclear Envelope Assembly and Disassembly During the Cell Cycle

Xenopus egg extracts treated with the protein kinase inhibitor 6-dimethylaminopurine (6-DMAP) are unable to support the initiation of DNA replication. Nuclei assembled in 6-DMAP extracts behave as though they are in G2, and will not undergo another round of DNA replication until passage through mitosis. 6-DMAP extracts are functionally devoid of a replication factor that modifies chromatin in early G1 before nuclear envelope assembly, but which is itself incapable of crossing the nuclear envelope. This chromatin modification is capable of supporting only a single round of semiconservative replication. The behavior of this replication factor is sufficient to explain why eukaryotic DNA is replicated once and only once in each cell cycle, and conforms to the previous model of a Replication Licensing Factor. Cell cycle analysis shows that this putative Licensing Factor is inactive during metaphase, but becomes rapidly activated on exit from metaphase when it can modify chromatin before nuclear envelope assembly is complete.

Download Full-text

Faculty Opinions recommendation of Role of importin-beta in the control of nuclear envelope assembly by Ran.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1007103.88057 ◽

2002 ◽

Author(s):

Mary Dasso

Keyword(s):

Nuclear Envelope ◽

Importin Beta ◽

Nuclear Envelope Assembly

Download Full-text

OASIS/CREB3L1 is a factor that responds to nuclear envelope stress

Cell Death Discovery ◽

10.1038/s41420-021-00540-x ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Yasunao Kamikawa ◽

Atsushi Saito ◽

Koji Matsuhisa ◽

Masayuki Kaneko ◽

Rie Asada ◽

...

Keyword(s):

Cell Cycle ◽

Endoplasmic Reticulum ◽

Nuclear Envelope ◽

Genome Instability ◽

Nuclear Lamina ◽

Nuclear Deformation ◽

Membrane Domain ◽

Stress Response Pathway ◽

Envelope Stress ◽

Genome Activity

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.

Download Full-text

Mutational analyses of fs(1)Ya, an essential, developmentally regulated, nuclear envelope protein in Drosophila.

Genetics ◽

10.1093/genetics/141.4.1473 ◽

1995 ◽

Vol 141 (4) ◽

pp. 1473-1481 ◽

Cited By ~ 1

Author(s):

J Liu ◽

K Song ◽

M F Wolfner

Keyword(s):

Cell Cycle ◽

Embryonic Development ◽

Nuclear Envelope ◽

Envelope Protein ◽

Chromatin Condensation ◽

Cell Cycle Control ◽

Nuclear Lamina ◽

Mitotic Division ◽

Developmentally Regulated ◽

Egg Maturation

Abstract The fs(1)Ya protein (YA) is an essential, maternally encoded, nuclear lamina protein that is under both developmental and cell cycle control. A strong Ya mutation results in early arrest of embryos. To define the function of YA in the nuclear envelope during early embryonic development, we characterized the phenotypes of four Ya mutants alleles and determined their molecular lesions. Ya mutant embryos arrest with abnormal nuclear envelopes prior to the first mitotic division; a proportion of embryos from two leaky Ya mutants proceed beyond this but arrest after several abnormal divisions. Ya unfertilized eggs contain nuclei of different sizes and condensation states, apparently due to abnormal fusion of the meiotic products immediately after meiosis. Lamin is localized at the periphery of the uncondensed nuclei in these eggs. These results suggest that YA function is required during and after egg maturation to facilitate proper chromatin condensation, rather than to allow a lamin-containing nuclear envelope to form. Two leaky Ya alleles that partially complement have lesions at opposite ends of the YA protein, suggesting that the N- and C-termini are important for YA function and that YA might interact with itself either directly or indirectly.

Download Full-text

The microtubule aster formation and its role in nuclear envelope assembly around the sperm chromatin inXenopus egg extracts

Chinese Science Bulletin ◽

10.1007/bf03183977 ◽

2003 ◽

Vol 48 (18) ◽

pp. 1912-1918

Author(s):

Ning Yang ◽

Zhongcai Chen ◽

Ping Lu ◽

Chuanmao Zhang ◽

Zhonghe Zhai ◽

...

Keyword(s):

Nuclear Envelope ◽

Sperm Chromatin ◽

Egg Extracts ◽

Nuclear Envelope Assembly ◽

Microtubule Aster

Download Full-text

Morphology and behaviour of dinoflagellate chromosomes during the cell cycle and mitosis

Journal of Cell Science ◽

10.1242/jcs.113.7.1231 ◽

2000 ◽

Vol 113 (7) ◽

pp. 1231-1239 ◽

Cited By ~ 3

Author(s):

Y. Bhaud ◽

D. Guillebault ◽

J. Lennon ◽

H. Defacque ◽

M.O. Soyer-Gobillard ◽

...

Keyword(s):

Electron Microscopy ◽

Cell Cycle ◽

Confocal Microscopy ◽

Nuclear Envelope ◽

Chromosome Segregation ◽

Morphological Changes ◽

S Phase ◽

Chromosome Behaviour ◽

Double Number ◽

Do So

The morphology and behaviour of the chromosomes of dinoflagellates during the cell cycle appear to be unique among eukaryotes. We used synchronized and aphidicolin-blocked cultures of the dinoflagellate Crypthecodinium cohnii to describe the successive morphological changes that chromosomes undergo during the cell cycle. The chromosomes in early G(1) phase appeared to be loosely condensed with numerous structures protruding toward the nucleoplasm. They condensed in late G(1), before unwinding in S phase. The chromosomes in cells in G(2) phase were tightly condensed and had a double number of arches, as visualised by electron microscopy. During prophase, chromosomes elongated and split longitudinally, into characteristic V or Y shapes. We also used confocal microscopy to show a metaphase-like alignment of the chromosomes, which has never been described in dinoflagellates. The metaphase-like nucleus appeared flattened and enlarged, and continued to do so into anaphase. Chromosome segregation occurred via binding to the nuclear envelope surrounding the cytoplasmic channels and microtubule bundles. Our findings are summarized in a model of chromosome behaviour during the cell cycle.

Download Full-text

BAF is required for emerin assembly into the reforming nuclear envelope

Journal of Cell Science ◽

10.1242/jcs.114.24.4575 ◽

2001 ◽

Vol 114 (24) ◽

pp. 4575-4585 ◽

Cited By ~ 3

Author(s):

Tokuko Haraguchi ◽

Takako Koujin ◽

Miriam Segura-Totten ◽

Kenneth K. Lee ◽

Yosuke Matsuoka ◽

...

Keyword(s):

Nuclear Envelope ◽

Hela Cells ◽

Core Region ◽

Lamin B ◽

The Core ◽

Double Stranded Dna ◽

Recessive Form ◽

Nuclear Envelope Assembly

Mutations in emerin cause the X-linked recessive form of Emery-Dreifuss muscular dystrophy (EDMD). Emerin localizes at the inner membrane of the nuclear envelope (NE) during interphase, and diffuses into the ER when the NE disassembles during mitosis. We analyzed the recruitment of wildtype and mutant GFP-tagged emerin proteins during nuclear envelope assembly in living HeLa cells. During telophase, emerin accumulates briefly at the ‘core’ region of telophase chromosomes, and later distributes over the entire nuclear rim. Barrier-to-autointegration factor (BAF), a protein that binds nonspecifically to double-stranded DNA in vitro, co-localized with emerin at the ‘core’ region of chromosomes during telophase. An emerin mutant defective for binding to BAF in vitro failed to localize at the ‘core’ in vivo, and subsequently failed to localize at the reformed NE. In HeLa cells that expressed BAF mutant G25E, which did not show ‘core’ localization, the endogenous emerin proteins failed to localize at the ‘core’ region during telophase, and did not assemble into the NE during the subsequent interphase. BAF mutant G25E also dominantly dislocalized LAP2β and lamin A from the NE, but had no effect on the localization of lamin B. We conclude that BAF is required for the assembly of emerin and A-type lamins at the reforming NE during telophase, and may mediate their stability in the subsequent interphase.

Download Full-text

Ran GTPase Cycle and Importins α and β Are Essential for Spindle Formation and Nuclear Envelope Assembly in LivingCaenorhabditis elegans Embryos

Molecular Biology of the Cell ◽

10.1091/mbc.e02-06-0346 ◽

2002 ◽

Vol 13 (12) ◽

pp. 4355-4370 ◽

Cited By ~ 127

Author(s):

Peter Askjaer ◽

Vincent Galy ◽

Eva Hannak ◽

Iain W. Mattaj

Keyword(s):

Nuclear Envelope ◽

Cell Function ◽

Small Gtpase ◽

Spindle Formation ◽

Ran Gtpase ◽

Early Embryos ◽

Nuclear Envelope Assembly ◽

Importin Α ◽

Gtpase Cycle

The small GTPase Ran has been found to play pivotal roles in several aspects of cell function. We have investigated the role of the Ran GTPase cycle in spindle formation and nuclear envelope assembly in dividing Caenorhabditis elegans embryos in real time. We found that Ran and its cofactors RanBP2, RanGAP, and RCC1 are all essential for reformation of the nuclear envelope after cell division. Reducing the expression of any of these components of the Ran GTPase cycle by RNAi leads to strong extranuclear clustering of integral nuclear envelope proteins and nucleoporins. Ran, RanBP2, and RanGAP are also required for building a mitotic spindle, whereas astral microtubules are normal in the absence of these proteins. RCC1(RNAi) embryos have similar abnormalities in the initial phase of spindle formation but eventually recover to form a bipolar spindle. Irregular chromatin structures and chromatin bridges due to spindle failure were frequently observed in embryos where the Ran cycle was perturbed. In addition, connection between the centrosomes and the male pronucleus, and thus centrosome positioning, depends upon the Ran cycle components. Finally, we have demonstrated that both IMA-2 and IMB-1, the homologues of vertebrate importin α and β, are essential for both spindle assembly and nuclear formation in early embryos.

Download Full-text