Enhanced S phase delay and inhibition of replication of an undamaged shuttle vector in UVC-irradiated xeroderma pigmentosum variant

Bullock, Sharon; Cordeiro‐Stone, Marila

doi:10.1093/carcin/22.2.233

Cited by 17 publications

(11 citation statements)

References 59 publications

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“…A previous report suggesting that ATM was involved in the S checkpoint response to low-dose UVC (52) was done with SV40-transformed fibroblasts. Human fibroblasts transformed with the SV40 large T antigen were recently reported to be defective in S checkpoint responses to both IR and UVC (8). SV40-transformed fibroblasts also display defective G 1 and G 2 checkpoint responses to IR (37).…”

Section: Discussionmentioning

confidence: 99%

An ATR- and Chk1-Dependent S Checkpoint Inhibits Replicon Initiation following UVC-Induced DNA Damage

Heffernan

Simpson

Frank

et al. 2002

Molecular and Cellular Biology

232

236

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Inhibition of replicon initiation is a stereotypic DNA damage response mediated through S checkpointmechanisms not yet fully understood. Studies were undertaken to elucidate the function of checkpoint proteins in the inhibition of replicon initiation following irradiation with 254 nm UV light (UVC) of diploid human fibroblasts immortalized by the ectopic expression of telomerase. Velocity sedimentation analysis of nascent DNA molecules revealed a 50% inhibition of replicon initiation when normal human fibroblasts were treated with a low dose of UVC (1 J/m 2 ). Ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), and AT-like disorder fibroblasts, which lack an S checkpoint response when exposed to ionizing radiation, responded normally when exposed to UVC and inhibited replicon initiation. Pretreatment of normal and AT fibroblasts with caffeine or UCN-01, inhibitors of ATR (AT mutated and Rad3 related) and Chk1, respectively, abolished the S checkpoint response to UVC. Moreover, overexpression of kinase-inactive ATR in U2OS cells severely attenuated UVC-induced Chk1 phosphorylation and reversed the UVC-induced inhibition of replicon initiation, as did overexpression of kinase-inactive Chk1. Taken together, these data suggest that the UVC-induced S checkpoint response of inhibition of replicon initiation is mediated by ATR signaling through Chk-1 and is independent of ATM, Nbs1, and Mre11.Accurate replication and segregation of the human genome depends on interactions between cell cycle checkpoints and pathways of DNA repair. Cell cycle checkpoints are biochemical surveillance pathways that slow or arrest progression through the cell cycle, pending completion of essential events and/or repair of DNA damage. DNA damage checkpoints minimize the probability of replicating and segregating damaged DNA and therefore reduce the frequencies of mutations and chromosomal aberrations that are induced by genotoxic stress.

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Section: Discussionmentioning

confidence: 99%

An ATR- and Chk1-Dependent S Checkpoint Inhibits Replicon Initiation following UVC-Induced DNA Damage

Heffernan

Simpson

Frank

et al. 2002

Molecular and Cellular Biology

232

236

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“…The C-Tag cells (POLH-deficient cells), which are SV40-immortalized cells derived from xeroderma pigmentosum-variant patients, were provided generously by Professor William K. Kaufmann (24).…”

Section: Methodsmentioning

confidence: 99%

The Roles of DNA Polymerases κ and ι in the Error-free Bypass of N2-Carboxyalkyl-2′-deoxyguanosine Lesions in Mammalian Cells

Yuan

You²,

Andersen³

et al. 2011

Journal of Biological Chemistry

101

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To counteract the deleterious effects of DNA damage, cells are equipped with specialized polymerases to bypass DNA lesions. Previous biochemical studies revealed that DinB family DNA polymerases, including Escherichia coli DNA polymerase IV and human DNA polymerase , efficiently incorporate the correct nucleotide opposite some N DNA is susceptible to damage by endogenous and exogenous agents (1). To minimize cell death arising from replication blockage and mutations emanating from nucleotide misincorporation opposite the damage site, cells are equipped with several pathways to repair DNA lesions (2). Additionally, cells have evolved two major mechanisms to tolerate unrepaired DNA lesions (3), including homologous recombination and translesion synthesis (TLS) 2 (3). In this regard, synthesis past many DNA lesions requires the replacement of replicative DNA polymerases with one or a few specialized polymerases, most of which belong to the Y-family (4). Along this line, phylogenetic analysis revealed five branches of Y-family polymerases, which include UmuC, DinB, polymerase , polymerase , and REV1 (4, 5). All of these, except for UmuC, are found in eukaryotic cells (4,5). Apart from the Y-family DNA polymerases, some B-family DNA polymerases also participate in TLS. These include DNA polymerase II in Escherichia coli and polymerase , which is composed of the catalytic subunit REV3 and the regulatory subunit REV7, in eukaryotic cells (4, 5). These specialized DNA polymerases are characterized by their relatively low fidelity in replicating undamaged DNA but have the capability to bypass those DNA lesions that normally block DNA synthesis by replicative DNA polymerases (4). It was advocated that specialized DNA polymerases are evolved by nature to copy DNA base damage accurately, but they no longer bear the ability to replicate unmodified DNA with high fidelity (6). The best known example of this is the efficient and accurate bypass of cis,syn-cyclobutane pyrimidine dimers by polymerase (7,8), which is encoded by the xeroderma pigmentosum-variant gene (i.e. POLH) in humans (9). Xeroderma pigmentosum-variant patients exhibit elevated susceptibility to developing skin cancer (10). Several recent studies also demonstrated that DinB DNA polymerase, a Y-family polymerase conserved in all three kingdoms of life (11), can insert the correct dCMP opposite several N 2 -substituted guanine lesions at an efficiency that is similar to or better than opposite an unmodified guanine (12)(13)(14). The x-ray crystal structure of the catalytic core of human DNA polymerase , along with primer/template DNA and an incoming nucleotide, reveals the lack of steric hindrance in the minor groove at the primer-template junction (15), which may account for the tolerance of polymerase toward the minor groove N 2 -dG lesions. By using shuttle vector technology, we also showed that DinB (i.e. polymerase IV) is the major polymerase involved in the accurate bypass of the two diastereomers of N 2 -(1-carboxyethyl)-2Ј-deoxyguanosine (N 2 -CEdG) in ...

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“…We and other have previously shown that resumption of DNA synthesis after UVC irradiation is strongly impaired in the absence of polh [Bullock et al, 2001;Cordeiro-Stone et al, 2002;Despras et al, 2010]. In order to unravel the consequences of UBZ and PIP invalidation on S phase progression, cells were pulse-labeled with BrdU at various times after 7 J/m 2 and analyzed by flow cytometry (Supporting Information Fig.…”

Section: Resumption Of Dna Synthesis After Uvc Is Delayed In Single Mmentioning

confidence: 99%

Regulation of the specialized DNA polymerase eta: Revisiting the biological relevance of its PCNA‐ and ubiquitin‐binding motifs

Despras

Delrieu

Garandeau

et al. 2012

Environ and Mol Mutagen

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During translesion synthesis (TLS), low-fidelity polymerases of the Y-family polymerases bypass DNA damages that block the progression of conventional processive DNA polymerases, thereby allowing the completion of DNA replication. Among the TLS polymerases, DNA polymerase eta (polh) performs nucleotide incorporation past ultraviolet (UV) photoproducts and is deficient in cancer-prone xeroderma pigmentosum variant (XPV) syndrome. Upon UV irradiation, the DNA sliding clamp PCNA is monoubiquitylated on its conserved Lys-164. This event is considered to facilitate the TLS process in vivo since polh preferentially interacts with monoubiquitylated PCNA through its ubiquitin-binding domain (UBZ) as well as its PCNA interacting peptide (PIP)-box. However, recent observations questioned this model. Therefore, in this study, we re-examined the relative contribution of the regulatory UBZ and PIP domains of polh in response to UVC. We show that simultaneous invalidation of both motifs confers sensitivity to UVC, sensitization by low concentrations of caffeine, prolonged inhibition of DNA synthesis and persistent S phase checkpoint activation, all characteristic features of XPV cells. While each domain is essential for efficient accumulation of polh in replication factories, mutational inactivation of UBZ or PIP motif only confers a slight sensitivity to UVC indicating that, although informative, polh focus analysis is not a reliable tool to assess the polh's ability to function in TLS in vivo. Taken together, these data indicate that PIP and UBZ motifs are not required for recruitment but for retention of polh at sites of stalled replication forks. We propose that this is a way to ensure that a sufficient amount of the protein is available for its bypass function. Environ. Mol. Mutagen. 53:752-765, 2012. V V C 2012 Wiley Periodicals, Inc.

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Enhanced S phase delay and inhibition of replication of an undamaged shuttle vector in UVC-irradiated xeroderma pigmentosum variant

Cited by 17 publications

References 59 publications

An ATR- and Chk1-Dependent S Checkpoint Inhibits Replicon Initiation following UVC-Induced DNA Damage

An ATR- and Chk1-Dependent S Checkpoint Inhibits Replicon Initiation following UVC-Induced DNA Damage

The Roles of DNA Polymerases κ and ι in the Error-free Bypass of N2-Carboxyalkyl-2′-deoxyguanosine Lesions in Mammalian Cells

Regulation of the specialized DNA polymerase eta: Revisiting the biological relevance of its PCNA‐ and ubiquitin‐binding motifs

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