Translesion polymerase kappa-dependent DNA synthesis underlies replication fork recovery

Tonzi, Peter; Yin, Yandong; Lee, Chelsea Wei Ting; Rothenberg, Eli; Huang, Tony T.

doi:10.7554/elife.41426

Cited by 59 publications

(87 citation statements)

References 65 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3E, 3F). Consistent with previous reports (Coquel et al, 2018;Tonzi & Yin, 2018), depletion of SMARCAL1 slightly increased IdU/CldU ratio in control knockdown cells ( Fig. 3E), though the underlying reason is unclear.…”

Section: Nascent Strand Degradation Caused By Cst Deficiency Requiressupporting

confidence: 92%

Human CST complex protects replication fork stability by directly blocking MRE11 degradation of nascent strand DNA

Shiva

et al. 2019

Preprint

View full text Add to dashboard Cite

Degradation and collapse of stalled replication forks are main sources of genome instability, yet the molecular mechanism for protecting forks from degradation/collapse is not well understood. Here, we report that human CST (CTC1-STN1-TEN1), a single-stranded DNA binding protein complex, localizes at stalled forks and protects forks from MRE11 nuclease degradation upon replication perturbation. CST deficiency causes nascent strand degradation, ssDNA accumulation after fork stalling, and delay in replication recovery, leading to cellular sensitivity to fork stalling agents. Purified CST binds to 5' overhangs and directly blocks MRE11 degradation in vitro, and the DNA binding ability of CST is required for blocking MRE11-mediated nascent strand degradation. Finally, we uncover that CST and BRCA2 form non-overlapping foci upon fork stalling, and CST inactivation is synthetic with BRCA2 deficiency in inducing genome instability. Collectively, our findings identify CST as an important fork protector to preserve genome integrity under replication perturbation.

show abstract

Section: Nascent Strand Degradation Caused By Cst Deficiency Requiressupporting

confidence: 92%

Human CST complex protects replication fork stability by directly blocking MRE11 degradation of nascent strand DNA

Shiva

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…We noticed that loss of TLS polymerase Polκ partially phenocopies the fork stability defect in KR cells, suggesting that Polκ is one of the DNA polymerases involved in PCNA ubiquitination-mediated gap filing. However, DNA2 inhibition did not completely rescue the fork protection defect of Polκ-depleted cells, and indeed it was previously shown that loss of this polymerase results in MRE11-mediated fork degradation (Tonzi et al, 2018). This indicates that Polκ also plays a role in fork protection independently of PCNA ubiquitination.…”

Section: Pcna Ubiquitination and The Regulation Of Lagging Strand Repmentioning

confidence: 85%

PCNA ubiquitination protects stalled replication forks from DNA2-mediated degradation by regulating Okazaki fragment maturation and chromatin assembly

Thakar

Leung

Nicolae

et al. 2019

Preprint

View full text Add to dashboard Cite

Upon genotoxic stress, PCNA ubiquitination allows for replication of damaged DNA by recruiting lesion-bypass DNA polymerases. However, PCNA is also ubiquitinated during normal S-phase progression. By employing ubiquitination-deficient 293T and RPE1 cells generated through CRISPR/Cas9 genome editing, we show that this modification promotes cellular proliferation and suppression of genomic instability under normal growth conditions. Loss of PCNA-ubiquitination results in DNA2-mediated but MRE11independent nucleolytic degradation of nascent DNA at stalled replication forks. This degradation is linked to defective gap-filling in the wake of the replication fork, and incomplete Okazaki fragment synthesis and maturation, thus interfering with efficient PCNA unloading by ATAD5 and subsequent nucleosomal deposition by CAF-1.Moreover, concomitant loss of PCNA-ubiquitination and BRCA2 results in a synergistic increase in nascent DNA degradation and sensitivity to PARP-inhibitors. In conclusion, we show that by ensuring efficient Okazaki fragment maturation, PCNA-ubiquitination protects fork integrity and promotes the resistance of BRCA-deficient cells to PARPinhibitors.

show abstract

“…Nbs1-dependent phosphorylation of RPA2 recruits the MRN complex to DNA and involves extensive end-resection. A recent study found that hpol k protects stalled forks from Mre11 exonuclease activity to promote fork recovery (76). It is possible TDO inhibition in glioma cells leads to down-regulation of hpol k, which then results in both (a) diminished Chk1 activation and (b) increased resection by the MRN complex.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of tryptophan 2,3-dioxygenase impairs DNA damage tolerance and repair in glioma cells

Reed

Maddukuri

Ketkar

et al. 2020

Preprint

View full text Add to dashboard Cite

Aberrant expression of tryptophan 2,3-dioxygenase (TDO) is a determinant of malignancy and immune response in gliomas in part through kynurenine (KYN)-mediated activation of the aryl hydrocarbon receptor (AhR). In the current study, we investigated the hypothesis that TDO activation in gliomas has a broad impact upon genome maintenance -promoting tolerance of replication stress (RS) and repair of DNA damage. We report that inhibition of TDO activity attenuated recovery from hydroxyurea (HU)-induced RS and increased the genotoxic effects of bis-chloroethylnitrosourea (BCNU), as fork progress was impeded when TDO-deficient glioma cells were treated with BCNU. Activation of the Chk1 arm of the replication stress response (RSR) was reduced when TDO activity was blocked prior to treatment with BCNU, whereas phosphorylation of serine 33 (pS33) on replication protein A (RPA) was enhanced -indicative of increased fork collapse. Restoration of KYN levels protected against some replication-associated effects of BCNU. Inhibition of TDO activity had a strong anti-proliferative effect on glioma-derived cells -enhancing the cytotoxic effects of BCNU. Analysis of results obtained using quantitative proteomics revealed TDOdependent changes in several signaling pathways -including down-regulation of DNA repair factors and sirtuin signaling. Consistent with these observations, inhibition of TDO diminished SIRT7 recruitment to chromatin, which increased histone H3K18 acetylation -a key mark involved in 53BP1 recruitment to sites of DNA damage. Cells lacking TDO activity exhibited defective recruitment of 53BP1 to gH2AX foci, which corresponded with delayed repair of BCNU-induced DNA breaks. Addition of exogenous KYN increased the rate of break repair. The discovery that TDO activity modulates sensitivity to DNA damage by fueling SIRT7/53BP1 localization to chromatin and repair of BCNU-induced DNA damage highlights the potential for tumor-specific metabolic changes to influence genome stability and may have implications for glioma biology and treatment strategies.

show abstract

Translesion polymerase kappa-dependent DNA synthesis underlies replication fork recovery

Cited by 59 publications

References 65 publications

Human CST complex protects replication fork stability by directly blocking MRE11 degradation of nascent strand DNA

Human CST complex protects replication fork stability by directly blocking MRE11 degradation of nascent strand DNA

PCNA ubiquitination protects stalled replication forks from DNA2-mediated degradation by regulating Okazaki fragment maturation and chromatin assembly

Inhibition of tryptophan 2,3-dioxygenase impairs DNA damage tolerance and repair in glioma cells

Contact Info

Product

Resources

About