scholarly journals Replication intermediate architecture reveals the chronology of DNA damage tolerance pathways at UV-stalled replication forks in human cells

2020 ◽  
Author(s):  
Yann Benureau ◽  
Caroline Pouvelle ◽  
Eliana Moreira Tavares ◽  
Pauline Dupaigne ◽  
Emmanuelle Despras ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Replication Fork ◽  
Damage Tolerance ◽  
Dna Lesions ◽  
Human Cells ◽  
Compensatory Mechanism ◽  
Dna Damage Tolerance ◽  
Replication Intermediate

AbstractDNA lesions in S phase threaten genome stability. The DNA damage tolerance (DDT) pathways overcome these obstacles and allow completion of DNA synthesis by the use of specialised translesion (TLS) DNA polymerases or through recombination-related processes. However, how these mechanisms coordinate with each other and with bulk replication remain elusive. To address these issues, we monitored the variation of replication intermediate architecture in response to ultraviolet irradiation using transmission electron microscopy. We show that the TLS polymerase η, able to accurately bypass the major UV lesion and mutated in the skin cancer-prone xeroderma pigmentosum variant (XPV) syndrome, acts at the replication fork to resolve uncoupling and prevent post-replicative gap accumulation. Repriming occurs as a compensatory mechanism when this on-the-fly mechanism cannot operate, and is therefore predominant in XPV cells. Interestingly, our data support a recombination-independent function of RAD51 at the replication fork to sustain repriming. Finally, we provide evidence for the post-replicative commitment of recombination in gap repair and for pioneering observations of in vivo recombination intermediates. Altogether, we propose a chronology of UV damage tolerance in human cells that highlights the key role of polη in shaping this response and ensuring the continuity of DNA synthesis.

scholarly journals RuvAB and RecG Are Not Essential for the Recovery of DNA Synthesis Following UV-Induced DNA Damage in Escherichia coli

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1631-1640 ◽  
Author(s):  
Janet R Donaldson ◽  
Charmain T Courcelle ◽  
Justin Courcelle
Keyword(s):  
Dna Damage ◽  
Dna Synthesis ◽  
Dna Lesions ◽  
Replication Forks ◽  
Wild Type ◽  
Replication Machinery ◽  
Dna Junctions ◽  
Fork Regression

Abstract Ultraviolet light induces DNA lesions that block the progression of the replication machinery. Several models speculate that the resumption of replication following disruption by UV-induced DNA damage requires regression of the nascent DNA or migration of the replication machinery away from the blocking lesion to allow repair or bypass of the lesion to occur. Both RuvAB and RecG catalyze branch migration of three- and four-stranded DNA junctions in vitro and are proposed to catalyze fork regression in vivo. To examine this possibility, we characterized the recovery of DNA synthesis in ruvAB and recG mutants. We found that in the absence of either RecG or RuvAB, arrested replication forks are maintained and DNA synthesis is resumed with kinetics that are similar to those in wild-type cells. The data presented here indicate that RecG- or RuvAB-catalyzed fork regression is not essential for DNA synthesis to resume following arrest by UV-induced DNA damage in vivo.

scholarly journals DNA-damage tolerance mediated by PCNA•Ub fusions in human cells is dependent on Rev1 but not Polη

2013 ◽  
Vol 41 (15) ◽  
pp. 7356-7369 ◽  
Author(s):  
Zhoushuai Qin ◽  
Mengxue Lu ◽  
Xin Xu ◽  
Michelle Hanna ◽  
Naoko Shiomi ◽  
...  
Keyword(s):  
Dna Damage ◽  
Damage Tolerance ◽  
Human Cells ◽  
Dna Damage Tolerance

scholarly journals Elevated Hedgehog activity contributes to attenuated DNA damage responses in aged hematopoietic cells

Leukemia ◽  
2019 ◽  
Vol 34 (4) ◽  
pp. 1125-1134
Author(s):  
Annika Scheffold ◽  
Ali H. Baig ◽  
Zhiyang Chen ◽  
Sarah E. von Löhneysen ◽  
Friedrich Becker ◽  
...  
Keyword(s):  
Dna Damage ◽  
Therapeutic Strategy ◽  
Damage Tolerance ◽  
Dna Lesions ◽  
Hematopoietic Progenitors ◽  
Dna Damage Tolerance ◽  
Hematopoietic System ◽  
Dna Damage Responses ◽  
Underlying Mechanisms ◽  
Bulky Dna Lesions

AbstractAccumulation of DNA damage and myeloid-skewed differentiation characterize aging of the hematopoietic system, yet underlying mechanisms remain incompletely understood. Here, we show that aging hematopoietic progenitor cells particularly of the myeloid branch exhibit enhanced resistance to bulky DNA lesions—a relevant type of DNA damage induced by toxins such as cancer drugs or endogenous aldehydes. We identified aging-associated activation of the Hedgehog (Hh) pathway to be connected to this phenotype. Inhibition of Hh signaling reverts DNA damage tolerance and DNA damage-resistant proliferation in aged hematopoietic progenitors. Vice versa, elevating Hh activity in young hematopoietic progenitors is sufficient to impair DNA damage responses. Altogether, these findings provide experimental evidence for aging-associated increases in Hh activity driving DNA damage tolerance in myeloid progenitors and myeloid-skewed differentiation. Modulation of Hh activity could thus be explored as a therapeutic strategy to prevent DNA damage tolerance, myeloid skewing, and disease development in the aging hematopoietic system.

scholarly journals Monoubiquitylation of histone H2B contributes to the bypass of DNA damage during and after DNA replication

2017 ◽  
Vol 114 (11) ◽  
pp. E2205-E2214 ◽  
Author(s):  
Shih-Hsun Hung ◽  
Ronald P. Wong ◽  
Helle D. Ulrich ◽  
Cheng-Fu Kao
Keyword(s):  
Dna Damage ◽  
Replication Fork ◽  
Dna Lesions ◽  
Template Switching ◽  
Lesion Bypass ◽  
Dna Damage Tolerance ◽  
Cytological Evidence ◽  
Histone H2b ◽  
Chromatin Dynamics ◽  
Dna Lesion

DNA lesion bypass is mediated by DNA damage tolerance (DDT) pathways and homologous recombination (HR). The DDT pathways, which involve translesion synthesis and template switching (TS), are activated by the ubiquitylation (ub) of PCNA through components of the RAD6-RAD18 pathway, whereas the HR pathway is independent of RAD18. However, it is unclear how these processes are coordinated within the context of chromatin. Here we show that Bre1, an ubiquitin ligase specific for histone H2B, is recruited to chromatin in a manner coupled to replication of damaged DNA. In the absence of Bre1 or H2Bub, cells exhibit accumulation of unrepaired DNA lesions. Consequently, the damaged forks become unstable and resistant to repair. We provide physical, genetic, and cytological evidence that H2Bub contributes toward both Rad18-dependent TS and replication fork repair by HR. Using an inducible system of DNA damage bypass, we further show that H2Bub is required for the regulation of DDT after genome duplication. We propose that Bre1-H2Bub facilitates fork recovery and gap-filling repair by controlling chromatin dynamics in response to replicative DNA damage.

scholarly journals Maturation of telomere 3’-overhangs is linked to the replication stress response

2020 ◽  
Author(s):  
Erin E. Henninger ◽  
Pascale Jolivet ◽  
Emilie Fallet ◽  
Mohcen Benmounah ◽  
Zhou Xu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Stress Response ◽  
Ubiquitin Ligase ◽  
Replication Fork ◽  
Damage Tolerance ◽  
Dna Helicase ◽  
Dna Damage Tolerance ◽  
Telomeric Repeats ◽  
Telomere Replication

AbstractPassage of the replication fork through telomeric repeats necessitates additional DNA processing by DNA repair factors, to regenerate the terminal 3’-overhang structure at leading telomeres. These factors are prevented from promoting telomeric recombination or fusion by an uncharacterized mechanism. Here we show that Rad5, a DNA helicase and ubiquitin ligase involved in the DNA damage tolerance pathway, participates in this mechanism. Rad5 is enriched at telomeres during telomere replication. Accelerated senescence seen in the absence of telomerase and Rad5, can be compensated for by a pathway involving the Rad51 recombinase and counteracted by the helicase Srs2. However, this pathway is only active at short telomeres. Instead, the ubiquitous activity of Rad5 during telomere replication is necessary for the proper reconstitution of the telomeric 3’-overhang, indicating that Rad5 is required to coordinate telomere maturation during telomere replication.

scholarly journals DNA damage tolerance in stem cells, ageing, mutagenesis, disease and cancer therapy

2019 ◽  
Vol 47 (14) ◽  
pp. 7163-7181 ◽  
Author(s):  
Bas Pilzecker ◽  
Olimpia Alessandra Buoninfante ◽  
Heinz Jacobs
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Damage Tolerance ◽  
Essential Feature ◽  
Dna Lesions ◽  
Template Switching ◽  
Dna Damage Tolerance ◽  
Response Network ◽  
Damage Response ◽  
Fork Stalling

AbstractThe DNA damage response network guards the stability of the genome from a plethora of exogenous and endogenous insults. An essential feature of the DNA damage response network is its capacity to tolerate DNA damage and structural impediments during DNA synthesis. This capacity, referred to as DNA damage tolerance (DDT), contributes to replication fork progression and stability in the presence of blocking structures or DNA lesions. Defective DDT can lead to a prolonged fork arrest and eventually cumulate in a fork collapse that involves the formation of DNA double strand breaks. Four principal modes of DDT have been distinguished: translesion synthesis, fork reversal, template switching and repriming. All DDT modes warrant continuation of replication through bypassing the fork stalling impediment or repriming downstream of the impediment in combination with filling of the single-stranded DNA gaps. In this way, DDT prevents secondary DNA damage and critically contributes to genome stability and cellular fitness. DDT plays a key role in mutagenesis, stem cell maintenance, ageing and the prevention of cancer. This review provides an overview of the role of DDT in these aspects.

scholarly journals Mechanisms for Maintaining Eukaryotic Replisome Progression in the Presence of DNA Damage

2021 ◽  
Vol 8 ◽  
Author(s):  
Thomas A. Guilliam
Keyword(s):  
Dna Damage ◽  
Single Molecule ◽  
Replication Fork ◽  
Genome Stability ◽  
Genome Duplication ◽  
Damage Tolerance ◽  
Tolerance Mechanisms ◽  
Dna Damage Tolerance ◽  
Replication Fork Progression ◽  
The Impact

The eukaryotic replisome coordinates template unwinding and nascent-strand synthesis to drive DNA replication fork progression and complete efficient genome duplication. During its advancement along the parental template, each replisome may encounter an array of obstacles including damaged and structured DNA that impede its progression and threaten genome stability. A number of mechanisms exist to permit replisomes to overcome such obstacles, maintain their progression, and prevent fork collapse. A combination of recent advances in structural, biochemical, and single-molecule approaches have illuminated the architecture of the replisome during unperturbed replication, rationalised the impact of impediments to fork progression, and enhanced our understanding of DNA damage tolerance mechanisms and their regulation. This review focusses on these studies to provide an updated overview of the mechanisms that support replisomes to maintain their progression on an imperfect template.

scholarly journals PCNA Ubiquitylation: Instructive or Permissive to DNA Damage Tolerance Pathways?

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1543
Author(s):  
Jun Che ◽  
Xin Hong ◽  
Hai Rao
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Damage Tolerance ◽  
Translesion Synthesis ◽  
Dna Lesions ◽  
Template Switching ◽  
Dna Damage Tolerance ◽  
Future Studies ◽  
Dna Lesion ◽  
Replicative Polymerases

DNA lesions escaping from repair often block the DNA replicative polymerases required for DNA replication and are handled during the S/G2 phases by the DNA damage tolerance (DDT) mechanisms, which include the error-prone translesion synthesis (TLS) and the error-free template switching (TS) pathways. Where the mono-ubiquitylation of PCNA K164 is critical for TLS, the poly-ubiquitylation of the same residue is obligatory for TS. However, it is not known how cells divide the labor between TLS and TS. Due to the fact that the type of DNA lesion significantly influences the TLS and TS choice, we propose that, instead of altering the ratio between the mono- and poly-Ub forms of PCNA, the competition between TLS and TS would automatically determine the selection between the two pathways. Future studies, especially the single integrated lesion “i-Damage” system, would elucidate detailed mechanisms governing the choices of specific DDT pathways.

Sign in / Sign up

Export Citation Format

Share Document