A new sub‐pathway of long‐patch base excision repair involving 5′ gap formation |
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| Authors: | Sharon Camacho Swetha Parvathaneni Sujata Choudhury Amrita Cheema Yi Bai Pooja Khatkar Hayriye Verda Erkizan Furqan Sami Yan Su Orlando D Schärer Sudha Sharma Rabindra Roy |
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| Institution: | 1. Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA;2. Department of Biochemistry and Molecular Biology, College of Medicine, Howard University, Washington, DC, USA;3. Department of Pharmacological Sciences & Department of Chemistry, Stony Brook University, Stony Brook, NY, USA |
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| Abstract: | Base excision repair (BER) is one of the most frequently used cellular DNA repair mechanisms and modulates many human pathophysiological conditions related to DNA damage. Through live cell and in vitro reconstitution experiments, we have discovered a major sub‐pathway of conventional long‐patch BER that involves formation of a 9‐nucleotide gap 5′ to the lesion. This new sub‐pathway is mediated by RECQ1 DNA helicase and ERCC1‐XPF endonuclease in cooperation with PARP1 poly(ADP‐ribose) polymerase and RPA. The novel gap formation step is employed during repair of a variety of DNA lesions, including oxidative and alkylation damage. Moreover, RECQ1 regulates PARP1 auto‐(ADP‐ribosyl)ation and the choice between long‐patch and single‐nucleotide BER, thereby modulating cellular sensitivity to DNA damage. Based on these results, we propose a revised model of long‐patch BER and a new key regulation point for pathway choice in BER. |
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| Keywords: | BER pathway switch oxidative damage PARP inhibition RECQ1 XPF‐ERCC1 |
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