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Updated: Mar 18, 2026
Visualizing and Quantifying Endonuclease-Based Site-Specific DNA Damage
Published on: August 21, 2021
DNA damage tolerance pathway involving DNA polymerase ι and the tumor suppressor p53 regulates DNA replication fork
Stephanie Hampp1, Tina Kiessling1, Kerstin Buechle1
1Department of Obstetrics and Gynecology, Ulm University, D-89075 Ulm, Germany;
Abstract:
DNA damage tolerance facilitates the progression of replication forks that have encountered obstacles on the template strands. It involves either translesion DNA synthesis initiated by proliferating cell nuclear antigen monoubiquitination or less well-characterized fork reversal and template switch mechanisms. Herein, we characterize a novel tolerance pathway requiring the tumor suppressor p53, the translesion polymerase ι (POLι), the ubiquitin ligase Rad5-related helicase-like transcription factor (HLTF), and the SWI/SNF catalytic subunit (SNF2) translocase zinc finger ran-binding domain containing 3 (ZRANB3). This novel p53 activity is lost in the exonuclease-deficient but transcriptionally active p53(H115N) mutant. Wild-type p53, but not p53(H115N), associates with POLι in vivo. Strikingly, the concerted action of p53 and POLι decelerates nascent DNA elongation and promotes HLTF/ZRANB3-dependent recombination during unperturbed DNA replication. Particularly after cross-linker-induced replication stress, p53 and POLι also act together to promote meiotic recombination enzyme 11 (MRE11)-dependent accumulation of (phospho-)replication protein A (RPA)-coated ssDNA. These results implicate a direct role of p53 in the processing of replication forks encountering obstacles on the template strand. Our findings define an unprecedented function of p53 and POLι in the DNA damage response to endogenous or exogenous replication stress.
Insights
A new DNA damage tolerance pathway involves tumor suppressor p53 and polymerase ι (POLι), aiding replication fork progression. This pathway, crucial for DNA repair, utilizes HLTF/ZRANB3 and MRE11 to manage replication stress.
Area of Science:
- Molecular Biology
- Genetics
- Cellular Biology
Background:
- DNA damage tolerance is essential for replication fork progression when encountering template strand obstacles.
- Known mechanisms include translesion DNA synthesis and fork reversal/template switching.
Purpose of the Study:
- To characterize a novel DNA damage tolerance pathway involving tumor suppressor p53.
- To investigate the roles of p53, polymerase ι (POLι), HLTF, and ZRANB3 in replication fork management.
Main Methods:
- Characterization of a novel p53-dependent DNA tolerance pathway.
- In vivo association studies between wild-type p53 and POLι.
- Analysis of DNA replication dynamics and recombination during replication stress.
Main Results:
- A novel pathway requires p53, POLι, HLTF, and ZRANB3.
- Wild-type p53, but not p53(H115N) mutant, associates with POLι.
- p53 and POLι decelerate DNA elongation and promote HLTF/ZRANB3-dependent recombination.
- p53 and POLι promote MRE11-dependent ssDNA accumulation under replication stress.
Conclusions:
- p53 directly participates in processing replication forks encountering template strand obstacles.
- p53 and POLι have an unprecedented function in the DNA damage response to replication stress.
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