The APE2 nuclease is essential for DNA double-strand break repair by microhomology-mediated end joining

Fleury, Hubert; MacEachern, Myles K; Stiefel, Clara M; Anand, Roopesh; Sempeck, Colin; Nebenfuehr, Benjamin; Maurer-Alcalá, Kelper; Ball, Kerri A.; Proctor, Bruce; Beláň, Ondrej; Taylor, E. Stewart; Ortega, Raquel; Dodd, Benjamin; Weatherly, Laila; Dansoko, Djelika; Leung, Justin; Boulton, Simon J.; Arnoult, Nausica

doi:10.1016/j.molcel.2023.03.017

Cited by 13 publications

(6 citation statements)

References 107 publications

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“…Our genome-wide screen identified a set of genes that were preferentially depleted in TKO cells, including hits previously reported to be essential for the survival of BRCA2 null cells, such as FEN1, RNaseH2A/B/C (Zimmermann et al, 2018), CIP2A (Adam et al, 2021), and ALC1 (Verma et al, 2021) (Fig. S1E), and known MMEJ factors, including POLQ, HMCES (Shukla et al, 2020), andAPEX2 (Alvarez-Quilon et al, 2020;Fleury et al, 2022;Mengwasser et al, 2019) (Fig. S1F).…”

Section: Crispr/cas9 Synthetic Lethal Screen Uncovers the Full Spectr...mentioning

confidence: 98%

“…In mammalian cells, studies have demonstrated that following the formation of a DSB, short-range DNA end-resection by MRE11 and CtIP exposes flanking microhomologies that promote the annealing of opposite ends of the break (Lee-Theilen et al , 2011; Truong et al , 2013; Xie et al , 2009). When internal homologies are base-paired, they form single-stranded DNA (ssDNA) flaps that are cleaved by APEX2 and FEN1 (Fleury et al , 2022; Mengwasser et al , 2019; Sharma et al , 2015). Annealed intermediates are extended by Polθ (Arana et al , 2008; Chan et al , 2010) and sealed by XRCC1/LIG3 to complete end-joining (Audebert et al ., 2004).…”

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confidence: 99%

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RHINO restricts MMEJ activity to mitosis

Sfeir

Brambati

Sacco

et al. 2023

Preprint

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DNA double-strand breaks (DSBs) are toxic lesions that can lead to genome instability if not properly repaired. Breaks incurred in G1 phase of the cell cycle are predominantly fixed by non-homologous end-joining (NHEJ), while homologous recombination (HR) is the primary repair pathway in S and G2. Microhomology-mediated end-joining (MMEJ) is intrinsically error-prone and considered a backup DSB repair pathway that becomes essential when HR and NHEJ are compromised. In this study, we uncover MMEJ as the major DSB repair pathway in M phase. Using CRISPR/Cas9-based synthetic lethal screens, we identify subunits of the 9-1-1 complex (RAD9A-HUS1-RAD1) and its interacting partner, RHINO, as critical MMEJ factors. Mechanistically, we show that the function of 9-1-1 and RHINO in MMEJ is inconsistent with their well-established role in ATR signaling. Instead, RHINO plays an unexpected and essential role in directing mutagenic repair to M phase by directly binding to Polymerase theta and promoting its recruitment to DSBs in mitosis. In addition, we provide evidence that mitotic MMEJ repairs persistent DNA damage that originates in S phase but is not repaired by HR. The latter findings could explain the synthetic lethal relationship between POLQ and BRCA1/2 and the synergistic effect of PolQ and PARP inhibitors. In summary, our study identifies MMEJ as the primary pathway for repairing DSBs during mitosis and highlights an unanticipated role for RHINO in directing mutagenic repair to M phase.

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Section: Crispr/cas9 Synthetic Lethal Screen Uncovers the Full Spectr...mentioning

confidence: 98%

mentioning

confidence: 99%

RHINO restricts MMEJ activity to mitosis

Sfeir

Brambati

Sacco

et al. 2023

Preprint

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“…In mammalian cells, homologous recombination (HR) and DNA nonhomologous end joining (NHEJ) are the two primary DSB repair pathways. NHEJ predominates in DSB repair following radiation exposure, whereas HR plays a secondary role in DSB repair induced by radiation ( 5 , 8 ).…”

Section: Dna Damage Repairmentioning

confidence: 99%

The research progress on radiation resistance of cervical cancer

Liang,

Sheng,

et al. 2024

Front. Oncol.

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Cervical carcinoma is the most prevalent gynecology malignant tumor and ranks as the fourth most common cancer worldwide, thus posing a significant threat to the lives and health of women. Advanced and early-stage cervical carcinoma patients with high-risk factors require adjuvant treatment following surgery, with radiotherapy being the primary approach. However, the tolerance of cervical cancer to radiotherapy has become a major obstacle in its treatment. Recent studies have demonstrated that radiation resistance in cervical cancer is closely associated with DNA damage repair pathways, the tumor microenvironment, tumor stem cells, hypoxia, cell cycle arrest, and epigenetic mechanisms, among other factors. The development of tumor radiation resistance involves complex interactions between multiple genes, pathways, and mechanisms, wherein each factor interacts through one or more signaling pathways. This paper provides an overview of research progress on an understanding of the mechanism underlying radiation resistance in cervical cancer.

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“…S1, A to D). The synthetic lethal screen identified a set of genes that were preferentially depleted in TKO cells, including hits previously reported to be essential for the survival of BRCA2 -null cells—such as FEN1 ; RNaseH2A , RNaseH2B , and RNaseH2C ( 32 ); CIP2A ( 33 ); and ALC1 ( 34 )—as well as known MMEJ factors, including POLQ , HMCES ( 35 ), and APEX2 ( 14 – 16 , 36 ) (fig. S1, E to G).…”

Section: Resultsmentioning

confidence: 99%

“…In mammalian cells, studies have demonstrated that after DSB formation, short-range DNA end resection by MRE11 and CtIP exposes flanking microhomologies that promote the annealing of opposite ends of the break ( 11 – 13 ). When internal homologies are base paired, the resulting single-stranded DNA (ssDNA) flaps are cleaved by APEX2 and FEN1 ( 14 – 16 ). Annealed intermediates are extended by Polθ ( 17 – 19 ) and sealed by XRCC1 and LIG3 to complete the end joining ( 20 ).…”

mentioning

confidence: 99%

RHINO directs MMEJ to repair DNA breaks in mitosis

Brambati

Sacco

Porcella

et al. 2023

Science

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Non-homologous end-joining (NHEJ) and homologous recombination (HR) are the primary pathways for repairing DNA double-strand breaks (DSBs) during interphase, while microhomology-mediated end-joining (MMEJ) has been regarded as a backup mechanism. Through CRISPR/Cas9-based synthetic lethal screens, we identify subunits of the 9-1-1 complex (RAD9A-HUS1-RAD1) and its interacting partner, RHINO, as crucial MMEJ factors. We uncover an unexpected function for RHINO in restricting MMEJ to mitosis. RHINO accumulates in M phase, undergoes PLK1 phosphorylation, and interacts with polymerase theta (Polθ), enabling its recruitment to DSBs for subsequent repair. Additionally, we provide evidence that MMEJ activity in mitosis repairs persistent DSBs originating in S phase. Our findings offer insights into the synthetic lethal relationship between POLQ and BRCA1/2 and the synergistic effect of Polθ and PARP inhibitors.

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The APE2 nuclease is essential for DNA double-strand break repair by microhomology-mediated end joining

Cited by 13 publications

References 107 publications

RHINO restricts MMEJ activity to mitosis

RHINO restricts MMEJ activity to mitosis

The research progress on radiation resistance of cervical cancer

RHINO directs MMEJ to repair DNA breaks in mitosis

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