Replication Stress and Telomere Dysfunction Are Present in Cultured Human Embryonic Stem Cells

Janson, Christine; Nyhan, Kristine C.; Murnane, John P.

doi:10.1159/000441245

Cited by 3 publications

(2 citation statements)

References 31 publications

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“…Thus, we hypothesized that this damage might rather be associated with stalled or stressed DNA replication forks [ 23 ]. One region of particular interest was telomeres [ 58 ], as PARP1 had been identified as a telomere-binding protein, and some previous reports of telomere shortening have been associated with PARP1 inhibition or inactivation [ 41 – 44 ]. To explore this possibility, we — in a blinded fashion — analyzed 50 randomly-selected metaphase spreads from wild type and PARP1 −/− cells for the presence of signal-free ends.…”

Section: Resultsmentioning

confidence: 99%

PARP1 is required for preserving telomeric integrity but is dispensable for A-NHEJ

et al. 2018

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Poly-ADP ribose polymerase 1 (PARP1) is clinically important because of its synthetic lethality with breast cancer allele 1 and 2 mutations, which are causative for inherited breast and ovarian cancers. Biochemically, PARP1 is a single-stranded DNA break repair protein that is needed for preserving genomic integrity. In addition, PARP1 has been implicated in a veritable plethora of additional cellular pathways and thus its precise contribution(s) to human biology has remained obscure. To help address this deficiency, we utilized gene editing to construct genetically-null PARP1 human cancer cells. We found a minor role for PARP1 in an alternative form of DNA double-strand break (DSB) repair, but only when these cells were deficient for the classical form of DSB repair. Despite being proficient for DSB repair, however, cell cycle progression defects and elevated endogenous DNA damage signaling were observed. These deficiencies were instead linked to telomere defects, where PARP1−/− cells had short telomeres that co-localized with markers of endogenous DNA damage and were compromised in their ability to escape a telomere-driven crisis. Our data suggest that while PARP1 does not participate significantly in DNA DSB repair itself, it does prevent the incidence of telomeric DSBs, which, in turn, can drive genomic instability.

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Section: Resultsmentioning

confidence: 99%

PARP1 is required for preserving telomeric integrity but is dispensable for A-NHEJ

et al. 2018

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“…In mammals, TRF1 is involved in replication at telomeres, and TRF1 depletion causes replication fork stalling at telomeres and telomere fragility (Martínez et al, 2009;Sfeir et al, 2009). In human embryonic stem cells, telomeres are highly susceptible to replication stress, which can induce telomere dysfunction, indicated by abnormal telomere structures and TIF formation (Janson et al, 2015).…”

Section: The Response To Dysfunctional Telomeresmentioning

confidence: 99%

The DNA damage response at dysfunctional telomeres, and at interstitial and subtelomeric DNA double-strand breaks

Muraki

Murnane

2017

Genes Genet. Syst.

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In mammals, DNA double-strand breaks (DSBs) are primarily repaired by classical non-homologous end joining (C-NHEJ), although homologous recombination repair and alternative NHEJ (A-NHEJ), which involve DSB processing, can also occur. These pathways are tightly regulated to maintain chromosome integrity. The ends of chromosomes, called telomeres, contain telomeric DNA that forms a cap structure in cooperation with telomeric proteins to prevent the activation of the DNA damage response and chromosome fusion at chromosome termini. Telomeres and subtelomeric regions are poor substrates for DNA replication; therefore, regions near telomeres are prone to replication fork stalling and chromosome breakage. Moreover, DSBs near telomeres are poorly repaired. As a result, when DSBs occur near telomeres in normal cells, the cells stop proliferating, while in cancer cells, subtelomeric DSBs induce rearrangements due to the absence of cell cycle checkpoints. The sensitivity of subtelomeric regions to DSBs is due to the improper regulation of processing, because although C-NHEJ is functional at subtelomeric DSBs, excessive processing results in an increased frequency of large deletions and chromosome rearrangements involving A-NHEJ.

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Common Chemical Inductors of Replication Stress: Focus on Cell‐Based Studies

et al. 2017

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DNA replication is a highly demanding process regarding the energy and material supply and must be precisely regulated, involving multiple cellular feedbacks. The slowing down or stalling of DNA synthesis and/or replication forks is referred to as replication stress (RS). Owing to the complexity and requirements of replication, a plethora of factors may interfere and challenge the genome stability, cell survival or affect the whole organism. This review outlines chemical compounds that are known inducers of RS and commonly used in laboratory research. These compounds act on replication by direct interaction with DNA causing DNA crosslinks and bulky lesions (cisplatin), chemical interference with the metabolism of deoxyribonucleotide triphosphates (hydroxyurea), direct inhibition of the activity of replicative DNA polymerases (aphidicolin) and interference with enzymes dealing with topological DNA stress (camptothecin, etoposide). As a variety of mechanisms can induce RS, the responses of mammalian cells also vary. Here, we review the activity and mechanism of action of these compounds based on recent knowledge, accompanied by examples of induced phenotypes, cellular readouts and commonly used doses.

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Replication Stress and Telomere Dysfunction Are Present in Cultured Human Embryonic Stem Cells

Cited by 3 publications

References 31 publications

PARP1 is required for preserving telomeric integrity but is dispensable for A-NHEJ

PARP1 is required for preserving telomeric integrity but is dispensable for A-NHEJ

The DNA damage response at dysfunctional telomeres, and at interstitial and subtelomeric DNA double-strand breaks

Common Chemical Inductors of Replication Stress: Focus on Cell‐Based Studies

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