Stepwise requirements for polymerases δ and θ in theta-mediated end joining.

Autor: Stroik S; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Carvajal-Garcia J; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA., Gupta D; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA., Edwards A; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Luthman A; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Wyatt DW; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Dannenberg RL; Department of Chemistry, The Pennsylvania State University, University Park, PA, USA., Feng W; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Kunkel TA; Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA., Gupta GP; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.; Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA., Hedglin M; Department of Chemistry, The Pennsylvania State University, University Park, PA, USA., Wood R; Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center and The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA., Doublié S; Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA., Rothenberg E; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA., Ramsden DA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. Dale_ramsden@med.unc.edu.; Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. Dale_ramsden@med.unc.edu.; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. Dale_ramsden@med.unc.edu.
Jazyk: angličtina
Zdroj: Nature [Nature] 2023 Nov; Vol. 623 (7988), pp. 836-841. Date of Electronic Publication: 2023 Nov 15.
DOI: 10.1038/s41586-023-06729-7
Abstrakt: Timely repair of chromosomal double-strand breaks is required for genome integrity and cellular viability. The polymerase theta-mediated end joining pathway has an important role in resolving these breaks and is essential in cancers defective in other DNA repair pathways, thus making it an emerging therapeutic target 1 . It requires annealing of 2-6 nucleotides of complementary sequence, microhomologies, that are adjacent to the broken ends, followed by initiation of end-bridging DNA synthesis by polymerase θ. However, the other pathway steps remain inadequately defined, and the enzymes required for them are unknown. Here we demonstrate requirements for exonucleolytic digestion of unpaired 3' tails before polymerase θ can initiate synthesis, then a switch to a more accurate, processive and strand-displacing polymerase to complete repair. We show the replicative polymerase, polymerase δ, is required for both steps; its 3' to 5' exonuclease activity for flap trimming, then its polymerase activity for extension and completion of repair. The enzymatic steps that are essential and specific to this pathway are mediated by two separate, sequential engagements of the two polymerases. The requisite coupling of these steps together is likely to be facilitated by physical association of the two polymerases. This pairing of polymerase δ with a polymerase capable of end-bridging synthesis, polymerase θ, may help to explain why the normally high-fidelity polymerase δ participates in genome destabilizing processes such as mitotic DNA synthesis 2 and microhomology-mediated break-induced replication 3 .
(© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)
Databáze: MEDLINE
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