scholarly journals Etoposide Induces the Dispersal of DNA Ligase I from Replication Factories

2001 ◽  
Vol 12 (7) ◽  
pp. 2109-2118 ◽  
Author(s):  
Alessandra Montecucco ◽  
Rossella Rossi ◽  
Giovanni Ferrari ◽  
A. Ivana Scovassi ◽  
Ennio Prosperi ◽  
...  
Keyword(s):  
Dna Replication ◽  
Ataxia Telangiectasia ◽  
Topoisomerase Ii ◽  
Molecular Mechanisms ◽  
Kinase Inhibitor ◽  
Protein A ◽  
S Phase ◽  
Nuclear Antigen ◽  
Dna Ligase ◽  
Dna Ligase I

In eukaryotic cells DNA replication occurs in specific nuclear compartments, called replication factories, that undergo complex rearrangements during S-phase. The molecular mechanisms underlying the dynamics of replication factories are still poorly defined. Here we show that etoposide, an anticancer drug that induces double-strand breaks, triggers the redistribution of DNA ligase I and proliferating cell nuclear antigen from replicative patterns and the ensuing dephosphorylation of DNA ligase I. Moreover, etoposide triggers the formation of RPA foci, distinct from replication factories. The effect of etoposide on DNA ligase I localization is prevented by aphidicolin, an inhibitor of DNA replication, and by staurosporine, a protein kinase inhibitor and checkpoints' abrogator. We suggest that dispersal of DNA ligase I is triggered by an intra-S-phase checkpoint activated when replicative forks meet topoisomerase II-DNA–cleavable complexes. However, etoposide treatment of ataxia telangiectasia cells demonstrated that ataxia-telangiectasia-mutated activity is not required for the disassembly of replication factories and the formation of replication protein A foci.

scholarly journals ATAD5 regulates the lifespan of DNA replication factories by modulating PCNA level on the chromatin

2012 ◽  
Vol 200 (1) ◽  
pp. 31-44 ◽  
Author(s):  
Kyoo-young Lee ◽  
Haiqing Fu ◽  
Mirit I. Aladjem ◽  
Kyungjae Myung
Keyword(s):  
Dna Replication ◽  
Molecular Mechanisms ◽  
S Phase ◽  
Nuclear Antigen ◽  
Spatial Regulation ◽  
Replication Factory ◽  
G2 Phase ◽  
Phase Progression ◽  
Temporal And Spatial ◽  
Proliferating Cell

Temporal and spatial regulation of the replication factory is important for efficient DNA replication. However, the underlying molecular mechanisms are not well understood. Here, we report that ATAD5 regulates the lifespan of replication factories. Reduced expression of ATAD5 extended the lifespan of replication factories by retaining proliferating cell nuclear antigen (PCNA) and other replisome proteins on the chromatin during and even after DNA synthesis. This led to an increase of inactive replication factories with an accumulation of replisome proteins. Consequently, the overall replication rate was decreased, which resulted in the delay of S-phase progression. Prevalent detection of PCNA foci in G2 phase cells after ATAD5 depletion suggests that defects in the disassembly of replication factories persist after S phase is complete. ATAD5-mediated regulation of the replication factory and PCNA required an intact ATAD5 ATPase domain. Taken together, our data imply that ATAD5 regulates the cycle of DNA replication factories, probably through its PCNA-unloading activity.

scholarly journals PCNA-mediated stabilization of E3 ligase RFWD3 at the replication fork is essential for DNA replication

2018 ◽  
Vol 115 (52) ◽  
pp. 13282-13287 ◽  
Author(s):  
Yo-Chuen Lin ◽  
Yating Wang ◽  
Rosaline Hsu ◽  
Sumanprava Giri ◽  
Susan Wopat ◽  
...  
Keyword(s):  
Dna Replication ◽  
Replication Fork ◽  
Protein A ◽  
Ring Finger ◽  
E3 Ligase ◽  
S Phase ◽  
Nuclear Antigen ◽  
Replication Forks ◽  
Interacting Protein ◽  
The Stability

RING finger and WD repeat domain-containing protein 3 (RFWD3) is an E3 ligase known to facilitate homologous recombination by removing replication protein A (RPA) and RAD51 from DNA damage sites. Further, RPA-mediated recruitment of RFWD3 to stalled replication forks is essential for interstrand cross-link repair. Here, we report that in unperturbed human cells, RFWD3 localizes at replication forks and associates with proliferating cell nuclear antigen (PCNA) via its PCNA-interacting protein (PIP) motif. PCNA association is critical for the stability of RFWD3 and for DNA replication. Cells lacking RFWD3 show slower fork progression, a prolonged S phase, and an increase in the loading of several replication-fork components on the chromatin. These findings all point to increased frequency of stalled forks in the absence of RFWD3. The S-phase defect is rescued by WT RFWD3, but not by the PIP mutant, suggesting that the interaction of RFWD3 with PCNA is critical for DNA replication. Finally, we observe reduced ubiquitination of RPA in cells lacking RFWD3. We conclude that the stabilization of RFWD3 by PCNA at the replication fork enables the polyubiquitination of RPA and its subsequent degradation for proper DNA replication.

scholarly journals Phosphorylation of Human DNA Ligase I Regulates Its Interaction with Replication Factor C and Its Participation in DNA Replication and DNA Repair

2009 ◽  
Vol 29 (8) ◽  
pp. 2042-2052 ◽  
Author(s):  
Sangeetha Vijayakumar ◽  
Barbara Dziegielewska ◽  
David S. Levin ◽  
Wei Song ◽  
Jinhu Yin ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Nuclear Antigen ◽  
Dna Ligase ◽  
Replication Factor C ◽  
Phase Form ◽  
Replication Factor ◽  
Human Dna ◽  
Dna Ligase I ◽  
Factor C

ABSTRACT Human DNA ligase I (hLigI) participates in DNA replication and excision repair via an interaction with proliferating cell nuclear antigen (PCNA), a DNA sliding clamp. In addition, hLigI interacts with and is inhibited by replication factor C (RFC), the clamp loader complex that loads PCNA onto DNA. Here we show that a mutant version of hLigI, which mimics the hyperphosphorylated M-phase form of hLigI, does not interact with and is not inhibited by RFC, demonstrating that inhibition of ligation is dependent upon the interaction between hLigI and RFC. To examine the biological relevance of hLigI phosphorylation, we isolated derivatives of the hLigI-deficient cell line 46BR.1G1 that stably express mutant versions of hLigI in which four serine residues phosphorylated in vivo were replaced with either alanine or aspartic acid. The cell lines expressing the phosphorylation site mutants of hLigI exhibited a dramatic reduction in proliferation and DNA synthesis and were also hypersensitive to DNA damage. The dominant-negative effects of the hLigI phosphomutants on replication and repair are due to the activation of cellular senescence, presumably because of DNA damage arising from replication abnormalities. Thus, appropriate phosphorylation of hLigI is critical for its participation in DNA replication and repair.

scholarly journals Mapping and Use of a Sequence that Targets DNA Ligase I to Sites of DNA Replication In Vivo

1997 ◽  
Vol 139 (3) ◽  
pp. 579-587 ◽  
Author(s):  
M. Cristina Cardoso ◽  
Cuthbert Joseph ◽  
Hans-Peter Rahn ◽  
Regina Reusch ◽  
Bernardo Nadal-Ginard ◽  
...  
Keyword(s):  
Dna Replication ◽  
Mammalian Cells ◽  
Fluorescent Protein ◽  
Functional Organization ◽  
S Phase ◽  
Dna Ligase ◽  
Chimeric Proteins ◽  
Dna Ligase I ◽  
Replication Foci

The mammalian nucleus is highly organized, and nuclear processes such as DNA replication occur in discrete nuclear foci, a phenomenon often termed “functional organization” of the nucleus. We describe the identification and characterization of a bipartite targeting sequence (amino acids 1–28 and 111–179) that is necessary and sufficient to direct DNA ligase I to nuclear replication foci during S phase. This targeting sequence is located within the regulatory, NH2-terminal domain of the protein and is dispensable for enzyme activity in vitro but is required in vivo. The targeting domain functions position independently at either the NH2 or the COOH termini of heterologous proteins. We used the targeting sequence of DNA ligase I to visualize replication foci in vivo. Chimeric proteins with DNA ligase I and the green fluorescent protein localized at replication foci in living mammalian cells and thus show that these subnuclear functional domains, previously observed in fixed cells, exist in vivo. The characteristic redistribution of these chimeric proteins makes them unique markers for cell cycle studies to directly monitor entry into S phase in living cells.

scholarly journals Regulation of DNA Replication Licensing and Re-Replication by Cdt1

2021 ◽  
Vol 22 (10) ◽  
pp. 5195
Author(s):  
Hui Zhang
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Genome Stability ◽  
E3 Ligase ◽  
S Phase ◽  
Replication Initiation ◽  
Nuclear Antigen ◽  
Repair Synthesis ◽  
Ubiquitin E3 Ligase

In eukaryotic cells, DNA replication licensing is precisely regulated to ensure that the initiation of genomic DNA replication in S phase occurs once and only once for each mitotic cell division. A key regulatory mechanism by which DNA re-replication is suppressed is the S phase-dependent proteolysis of Cdt1, an essential replication protein for licensing DNA replication origins by loading the Mcm2-7 replication helicase for DNA duplication in S phase. Cdt1 degradation is mediated by CRL4Cdt2 ubiquitin E3 ligase, which further requires Cdt1 binding to proliferating cell nuclear antigen (PCNA) through a PIP box domain in Cdt1 during DNA synthesis. Recent studies found that Cdt2, the specific subunit of CRL4Cdt2 ubiquitin E3 ligase that targets Cdt1 for degradation, also contains an evolutionarily conserved PIP box-like domain that mediates the interaction with PCNA. These findings suggest that the initiation and elongation of DNA replication or DNA damage-induced repair synthesis provide a novel mechanism by which Cdt1 and CRL4Cdt2 are both recruited onto the trimeric PCNA clamp encircling the replicating DNA strands to promote the interaction between Cdt1 and CRL4Cdt2. The proximity of PCNA-bound Cdt1 to CRL4Cdt2 facilitates the destruction of Cdt1 in response to DNA damage or after DNA replication initiation to prevent DNA re-replication in the cell cycle. CRL4Cdt2 ubiquitin E3 ligase may also regulate the degradation of other PIP box-containing proteins, such as CDK inhibitor p21 and histone methylase Set8, to regulate DNA replication licensing, cell cycle progression, DNA repair, and genome stability by directly interacting with PCNA during DNA replication and repair synthesis.

scholarly journals Periodic Expression of the Cyclin-dependent Kinase Inhibitor p57Kip2 in Trophoblast Giant Cells Defines a G2-like Gap Phase of the Endocycle

2000 ◽  
Vol 11 (3) ◽  
pp. 1037-1045 ◽  
Author(s):  
Naka Hattori ◽  
Tyler C. Davies ◽  
Lynn Anson-Cartwright ◽  
James C. Cross
Keyword(s):  
Dna Replication ◽  
Protein Targeting ◽  
Kinase Inhibitor ◽  
Phosphorylation Site ◽  
Giant Cells ◽  
S Phase ◽  
Stable Form ◽  
Cdk Inhibitor ◽  
Cyclin Dependent Kinase ◽  
Trophoblast Giant Cells

Endoreduplication is an unusual form of cell cycle in which rounds of DNA synthesis repeat in the absence of intervening mitoses. How G1/S cyclin-dependent kinase (Cdk) activity is regulated during the mammalian endocycle is poorly understood. We show here that expression of the G1/S Cdk inhibitor p57Kip2 is induced coincidentally with the transition to the endocycle in trophoblast giant cells.Kip2 mRNA is constitutively expressed during subsequent endocycles, but the protein level fluctuates. In trophoblast giant cells synchronized for the first few endocycles, the p57Kip2 protein accumulates only at the end of S-phase and then rapidly disappears a few hours before the onset of the next S-phase. The protein becomes stabilized by mutation of a C-terminal Cdk phosphorylation site. As a consequence, introduction of this stable form of p57Kip2 into giant cells blocks S-phase entry. These data imply that p57Kip2 is subject to phosphorylation-dependent turnover. Surprisingly, although this occurs in endoreduplicating giant cells, p57Kip2 is stable when ectopically expressed in proliferating trophoblast cells, indicating that these cells lack the mechanism for protein targeting and/or degradation. These data show that the appearance of p57Kip2punctuates the completion of DNA replication, whereas its turnover is subsequently required to initiate the next round of endoreduplication in trophoblast giant cells. Cyclical expression of a Cdk inhibitor, by terminating G1/S Cdk activity, may help promote the resetting of DNA replication machinery.

scholarly journals Proliferating cell nuclear antigen acts as a cytoplasmic platform controlling human neutrophil survival

2010 ◽  
Vol 207 (12) ◽  
pp. 2631-2645 ◽  
Author(s):  
Véronique Witko-Sarsat ◽  
Julie Mocek ◽  
Dikra Bouayad ◽  
Nicola Tamassia ◽  
Jean-Antoine Ribeil ◽  
...  
Keyword(s):  
Proliferating Cell Nuclear Antigen ◽  
Molecular Mechanisms ◽  
Kinase Inhibitor ◽  
Nuclear Antigen ◽  
Neutrophil Apoptosis ◽  
Proliferating Cells ◽  
Rna Transfection ◽  
Neutrophil Survival ◽  
Proliferating Cell

Neutrophil apoptosis is a highly regulated process essential for inflammation resolution, the molecular mechanisms of which are only partially elucidated. In this study, we describe a survival pathway controlled by proliferating cell nuclear antigen (PCNA), a nuclear factor involved in DNA replication and repairing of proliferating cells. We show that mature neutrophils, despite their inability to proliferate, express high levels of PCNA exclusively in their cytosol and constitutively associated with procaspases, presumably to prevent their activation. Notably, cytosolic PCNA abundance decreased during apoptosis, and increased during in vitro and in vivo exposure to the survival factor granulocyte colony-stimulating factor (G-CSF). Peptides derived from the cyclin-dependent kinase inhibitor p21, which compete with procaspases to bind PCNA, triggered neutrophil apoptosis thus demonstrating that specific modification of PCNA protein interactions affects neutrophil survival. Furthermore, PCNA overexpression rendered neutrophil-differentiated PLB985 myeloid cells significantly more resistant to TNF-related apoptosis-inducing ligand– or gliotoxin-induced apoptosis. Conversely, a decrease in PCNA expression after PCNA small interfering RNA transfection sensitized these cells to apoptosis. Finally, a mutation in the PCNA interdomain-connecting loop, the binding site for many partners, significantly decreased the PCNA-mediated antiapoptotic effect. These results identify PCNA as a regulator of neutrophil lifespan, thereby highlighting a novel target to potentially modulate pathological inflammation.

scholarly journals Cellular DNA Ligase I Is Recruited to Cytoplasmic Vaccinia Virus Factories and Masks the Role of the Vaccinia Ligase in Viral DNA Replication

2009 ◽  
Vol 6 (6) ◽  
pp. 563-569 ◽  
Author(s):  
Nir Paran ◽  
Frank S. De Silva ◽  
Tatiana G. Senkevich ◽  
Bernard Moss
Keyword(s):  
Dna Replication ◽  
Vaccinia Virus ◽  
Dna Ligase ◽  
Viral Dna ◽  
Viral Dna Replication ◽  
Dna Ligase I ◽  
Cellular Dna
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