scholarly journals Repair of DNA–Protein Cross-links in Mammalian Cells

Cell Cycle ◽  
2006 ◽  
Vol 5 (13) ◽  
pp. 1366-1370 ◽  
Author(s):  
Joyce T. Reardon ◽  
Yuan Cheng ◽  
Aziz Sancar
Keyword(s):  
Mammalian Cells ◽  
Cross Links

DNA-Protein Cross-Links: New Insights into their Formation and Repair in Irradiated Mammalian Cells

1986 ◽  
pp. 181-192 ◽  
Author(s):  
Nancy L. Oleinick ◽  
Song-mao Chiu ◽  
Libby R. Friedman ◽  
Liang-yan Xue ◽  
Narayani Ramakrishnan
Keyword(s):  
Mammalian Cells ◽  
Cross Links

scholarly journals Schizosaccharomyces pombe Checkpoint Response to DNA Interstrand Cross-Links

2003 ◽  
Vol 23 (13) ◽  
pp. 4728-4737 ◽  
Author(s):  
Sarah Lambert ◽  
Sarah J. Mason ◽  
Louise J. Barber ◽  
John A. Hartley ◽  
Jackie A. Pearce ◽  
...  
Keyword(s):  
Dna Damage ◽  
Schizosaccharomyces Pombe ◽  
Mammalian Cells ◽  
Excision Repair ◽  
S Phase ◽  
Repair Gene ◽  
Phase Arrest ◽  
S Phase Arrest ◽  
Interstrand Cross Links ◽  
Cross Links

ABSTRACT Drugs that produce covalent interstrand cross-links (ICLs) in DNA remain central to the treatment of cancer, but the cell cycle checkpoints activated by ICLs have received little attention. We have used the fission yeast, Schizosaccharomyces pombe, to elucidate the checkpoint responses to the ICL-inducing anticancer drugs nitrogen mustard and mitomycin C. First we confirmed that the repair pathways acting on ICLs in this yeast are similar to those in the main organisms studied to date (Escherichia coli, budding yeast, and mammalian cells), principally nucleotide excision repair and homologous recombination. We also identified and disrupted the S. pombe homologue of the Saccharomyces cerevisiae SNM1/PSO2 ICL repair gene and found that this activity is required for normal resistance to cross-linking agents, but not other forms of DNA damage. Survival and biochemical analysis indicated a key role for the “checkpoint Rad” family acting through the chk1-dependent DNA damage checkpoint in the ICL response. Rhp9-dependent phosphorylation of Chk1 correlates with G2 arrest following ICL induction. In cells able to bypass the G2 block, a second-cycle (S-phase) arrest was observed. Only a transient activation of the Cds1 DNA replication checkpoint factor occurs following ICL formation in wild-type cells, but this is increased and persists in G2 arrest-deficient mutants. This likely reflects the fraction of cells escaping the G2 damage checkpoint and arresting in the subsequent S phase due to ICL replication blocks. Disruption of cds1 confers increased resistance to ICLs, suggesting that this second-cycle S-phase arrest might be a lethal event.

scholarly journals The Structure-Specific Endonuclease Ercc1-Xpf Is Required To Resolve DNA Interstrand Cross-Link-Induced Double-Strand Breaks

2004 ◽  
Vol 24 (13) ◽  
pp. 5776-5787 ◽  
Author(s):  
Laura J. Niedernhofer ◽  
Hanny Odijk ◽  
Magda Budzowska ◽  
Ellen van Drunen ◽  
Alex Maas ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Mammalian Cells ◽  
Cell Cycle Progression ◽  
Strand Break ◽  
Sister Chromatid Exchanges ◽  
Wild Type ◽  
Cross Link ◽  
Interstrand Cross Links ◽  
Normal Metabolism ◽  
Cross Links

ABSTRACT Interstrand cross-links (ICLs) are an extremely toxic class of DNA damage incurred during normal metabolism or cancer chemotherapy. ICLs covalently tether both strands of duplex DNA, preventing the strand unwinding that is essential for polymerase access. The mechanism of ICL repair in mammalian cells is poorly understood. However, genetic data implicate the Ercc1-Xpf endonuclease and proteins required for homologous recombination-mediated double-strand break (DSB) repair. To examine the role of Ercc1-Xpf in ICL repair, we monitored the phosphorylation of histone variant H2AX (γ-H2AX). The phosphoprotein accumulates at DSBs, forming foci that can be detected by immunostaining. Treatment of wild-type cells with mitomycin C (MMC) induced γ-H2AX foci and increased the amount of DSBs detected by pulsed-field gel electrophoresis. Surprisingly, γ-H2AX foci were also induced in Ercc1 −/− cells by MMC treatment. Thus, DSBs occur after cross-link damage via an Ercc1-independent mechanism. Instead, ICL-induced DSB formation required cell cycle progression into S phase, suggesting that DSBs are an intermediate of ICL repair that form during DNA replication. In Ercc1 −/− cells, MMC-induced γ-H2AX foci persisted at least 48 h longer than in wild-type cells, demonstrating that Ercc1 is required for the resolution of cross-link-induced DSBs. MMC triggered sister chromatid exchanges in wild-type cells but chromatid fusions in Ercc1 −/− and Xpf mutant cells, indicating that in their absence, repair of DSBs is prevented. Collectively, these data support a role for Ercc1-Xpf in processing ICL-induced DSBs so that these cytotoxic intermediates can be repaired by homologous recombination.

scholarly journals Initiation of DNA interstrand cross-link repair in humans: the nucleotide excision repair system makes dual incisions 5' to the cross-linked base and removes a 22- to 28-nucleotide-long damage-free strand.

1997 ◽  
Vol 17 (12) ◽  
pp. 6822-6830 ◽  
Author(s):  
T Bessho ◽  
D Mu ◽  
A Sancar
Keyword(s):  
Dna Repair ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Repair System ◽  
Cross Link ◽  
Unique Challenge ◽  
Cell Extracts ◽  
Interstrand Cross Links ◽  
Cross Links ◽  
The Cross

Most DNA repair mechanisms rely on the redundant information inherent to the duplex to remove damaged nucleotides and replace them with normal ones, using the complementary strand as a template. Interstrand cross-links pose a unique challenge to the DNA repair machinery because both strands are damaged. To study the repair of interstrand cross-links by mammalian cells, we tested the activities of cell extracts of wild-type or excision repair-defective rodent cell lines and of purified human excision nuclease on a duplex with a site-specific cross-link. We found that in contrast to monoadducts, which are removed by dual incisions bracketing the lesion, the cross-link causes dual incisions, both 5' to the cross-link in one of the two strands. The net result is the generation of a 22- to 28-nucleotide-long gap immediately 5' to the cross-link. This gap may act as a recombinogenic signal to initiate cross-link removal.

scholarly journals Maturation of the Human Papillomavirus 16 Capsid

mBio ◽  
2014 ◽  
Vol 5 (4) ◽  
Author(s):  
Giovanni Cardone ◽  
Adam L. Moyer ◽  
Naiqian Cheng ◽  
Cynthia D. Thompson ◽  
Israel Dvoretzky ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Disulfide Bonds ◽  
Mammalian Cells ◽  
Structural Integrity ◽  
Regular Structure ◽  
Human Papillomaviruses ◽  
Cryo Electron Microscopy ◽  
Cross Links ◽  
Risk Of Cancer

ABSTRACTPapillomaviruses are a family of nonenveloped DNA viruses that infect the skin or mucosa of their vertebrate hosts. The viral life cycle is closely tied to the differentiation of infected keratinocytes. Papillomavirus virions are released into the environment through a process known as desquamation, in which keratinocytes lose structural integrity prior to being shed from the surface of the skin. During this process, virions are exposed to an increasingly oxidative environment, leading to their stabilization through the formation of disulfide cross-links between neighboring molecules of the major capsid protein, L1. We used time-lapse cryo-electron microscopy and image analysis to study the maturation of HPV16 capsids assembled in mammalian cells and exposed to an oxidizing environment after cell lysis. Initially, the virion is a loosely connected procapsid that, underin vitroconditions, condenses over several hours into the more familiar 60-nm-diameter papillomavirus capsid. In this process, the procapsid shrinks by ~5% in diameter, its pentameric capsomers change in structure (most markedly in the axial region), and the interaction surfaces between adjacent capsomers are consolidated. A C175S mutant that cannot achieve normal inter-L1 disulfide cross-links shows maturation-related shrinkage but does not achieve the fully condensed 60-nm form. Pseudoatomic modeling based on a 9-Å resolution reconstruction of fully mature capsids revealed C-terminal disulfide-stabilized “suspended bridges” that form intercapsomeric cross-links. The data suggest a model in which procapsids exist in a range of dynamic intermediates that can be locked into increasingly mature configurations by disulfide cross-linking, possibly through a Brownian ratchet mechanism.IMPORTANCEHuman papillomaviruses (HPVs) cause nearly all cases of cervical cancer, a major fraction of cancers of the penis, vagina/vulva, anus, and tonsils, and genital and nongenital warts. HPV types associated with a high risk of cancer, such as HPV16, are generally transmitted via sexual contact. The nonenveloped virion of HPVs shows a high degree of stability, allowing the virus to persist in an infectious form in environmental fomites. In this study, we used cryo-electron microscopy to elucidate the structure of the HPV16 capsid at different stages of maturation. The fully mature capsid adopts a rigid, highly regular structure stabilized by intermolecular disulfide bonds. The availability of a pseudoatomic model of the fully mature HPV16 virion should help guide understanding of antibody responses elicited by HPV capsid-based vaccines.

scholarly journals Nucleotide Excision Repair Eliminates Unique DNA-Protein Cross-links from Mammalian Cells

2007 ◽  
Vol 282 (31) ◽  
pp. 22592-22604 ◽  
Author(s):  
David J. Baker ◽  
Gerald Wuenschell ◽  
Liqun Xia ◽  
John Termini ◽  
Steven E. Bates ◽  
...  
Keyword(s):  
Nucleotide Excision Repair ◽  
Mammalian Cells ◽  
Excision Repair ◽  
Nucleotide Excision ◽  
Cross Links

Arsenite induces oxidative DNA adducts and DNA-protein cross-links in mammalian cells

2001 ◽  
Vol 31 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Tsu-Shing Wang ◽  
Tsung-Yang Hsu ◽  
Chiao-Hui Chung ◽  
Alexander S.S Wang ◽  
Da-Tian Bau ◽  
...  
Keyword(s):  
Dna Adducts ◽  
Mammalian Cells ◽  
Cross Links
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