Coordination of DNA–PK Activation and Nuclease Processing of DNA Termini in NHEJ

Pawelczak, Katherine S.; Bennett, Sara M; Turchi, John J.

doi:10.1089/ars.2010.3368

Cited by 30 publications

(27 citation statements)

References 92 publications

(104 reference statements)

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“…We also analyzed the phosphorylation of the RPA32 subunit at Thr21, which is mainly catalyzed by DNA-PK (43). DNA-PK is known to be activated following recruitment to the Ku heterodimer at the free ends of a DSB (44). Cells exposed to N-OH-PhIP showed a slight increase of phosphorylated RPA (pRPA), while concomitant inhibition of ATR by VE821 highly stimulated RPA phosphorylation at Thr21 (Figure 4E).…”

Section: Resultsmentioning

confidence: 99%

DNA damage response curtails detrimental replication stress and chromosomal instability induced by the dietary carcinogen PhIP

Mimmler¹,

Schmidt²,

Kraus³

et al. 2016

Nucleic Acids Research

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PhIP is an abundant heterocyclic aromatic amine (HCA) and important dietary carcinogen. Following metabolic activation, PhIP causes bulky DNA lesions at the C8-position of guanine. Although C8-PhIP-dG adducts are mutagenic, their interference with the DNA replication machinery and the elicited DNA damage response (DDR) have not yet been studied. Here, we analyzed PhIP-triggered replicative stress and elucidated the role of the apical DDR kinases ATR, ATM and DNA-PKcs in the cellular defense response. First, we demonstrate that PhIP induced C8-PhIP-dG adducts and DNA strand breaks. This stimulated ATR-CHK1 signaling, phosphorylation of histone 2AX and the formation of RPA foci. In proliferating cells, PhIP treatment increased the frequency of stalled replication forks and reduced fork speed. Inhibition of ATR in the presence of PhIP-induced DNA damage strongly promoted the formation of DNA double-strand breaks, activation of the ATM-CHK2 pathway and hyperphosphorylation of RPA. The abrogation of ATR signaling potentiated the cell death response and enhanced chromosomal aberrations after PhIP treatment, while ATM and DNA-PK inhibition had only marginal effects. These results strongly support the notion that ATR plays a key role in the defense against cancer formation induced by PhIP and related HCAs.

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Section: Resultsmentioning

confidence: 99%

DNA damage response curtails detrimental replication stress and chromosomal instability induced by the dietary carcinogen PhIP

Mimmler¹,

Schmidt²,

Kraus³

et al. 2016

Nucleic Acids Research

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“…Removal of a damaged 3′ nucleoside by TDP1 leaves a 3′ phosphate, which can be removed by PNKP (40, 75–77). An important NHEJ end-processing factors is the Artemis nuclease, which can act alone as a 5′ exonuclease and as part of the DNA-PKcs:Artemis complex as a 5′- or 3′-endonuclease (2, 78). Additionally, APLF possess activities that can trim single-stranded 3′ extensions at a DSB (79, 80).…”

Section: Discussionmentioning

confidence: 99%

TDP1 promotes assembly of non-homologous end joining protein complexes on DNA

Heo

Summerlin

et al. 2015

DNA Repair

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The repair of DNA double-strand breaks (DSB) is central to the maintenance of genomic integrity. In tumor cells, the ability to repair DSBs predicts response to radiation and many cytotoxic anti-cancer drugs. DSB repair pathways include homologous recombination and non-homologous end joining (NHEJ). NHEJ is a template-independent mechanism, yet many NHEJ repair products carry limited genetic changes, which suggests that NHEJ includes mechanisms to minimize error. Proteins required for mammalian NHEJ include Ku70/80, the DNA-dependent protein kinase (DNA-PKcs), XLF/Cernunnos and the XRCC4:DNA ligase IV complex. NHEJ also utilizes accessory proteins that include DNA polymerases, nucleases, and other end-processing factors. In yeast, mutations of tyrosyl-DNA phosphodiesterase (TDP1) reduced NHEJ fidelity. TDP1 plays an important role in repair of topoisomerase-mediated DNA damage and 3′-blocking DNA lesions, and mutation of the human TDP1 gene results in an inherited human neuropathy termed SCAN1. We found that human TDP1 stimulated DNA binding by XLF and physically interacted with XLF to form TDP1:XLF:DNA complexes. TDP1:XLF interactions preferentially stimulated TDP1 activity on dsDNA as compared to ssDNA. TDP1 also promoted DNA binding by Ku70/80 and stimulated DNA-PK activity. Because Ku70/80 and XLF are the first factors recruited to the DSB at the onset of NHEJ, our data suggest a role for TDP1 during the early stages of mammalian NHEJ.

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“…Artemis, in combination with DNA-PK, functions as an endonuclease that processes DNA hairpins formed during V(D)J recombination [51]. This activity is also seen in the trimming of 3´ and 5´ overhangs on DSB ends wherein the 5´ is removed completely while the 3´ is shortened to 4-5 bases and subsequently to 2-3 bases upon prolonged incubation [52,53].…”

Section: Artemismentioning

confidence: 99%

End-processing nucleases and phosphodiesterases: An elite supporting cast for the non-homologous end joining pathway of DNA double-strand break repair

Menon

Povirk

2016

DNA Repair

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Coordination of DNA–PK Activation and Nuclease Processing of DNA Termini in NHEJ

Cited by 30 publications

References 92 publications

DNA damage response curtails detrimental replication stress and chromosomal instability induced by the dietary carcinogen PhIP

DNA damage response curtails detrimental replication stress and chromosomal instability induced by the dietary carcinogen PhIP

TDP1 promotes assembly of non-homologous end joining protein complexes on DNA

End-processing nucleases and phosphodiesterases: An elite supporting cast for the non-homologous end joining pathway of DNA double-strand break repair

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