2. Academic Validation
  3. Fanconi anemia-associated chromosomal radial formation is dependent on POLθ-mediated alternative end joining

Fanconi anemia-associated chromosomal radial formation is dependent on POLθ-mediated alternative end joining

  • Cell Rep. 2023 Apr 21;42(5):112428. doi: 10.1016/j.celrep.2023.112428.
Colette B Rogers 1,  Rachel E Kram 1,  Kevin Lin 2,  Chad L Myers 2,  Alexandra Sobeck 1,  Eric A Hendrickson 3,  Anja-Katrin Bielinsky 4
Affiliations

Affiliations

  • 1 Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA.
  • 2 Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
  • 3 Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: [email protected].
  • 4 Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: [email protected].
PMID: 37086407 DOI: 10.1016/j.celrep.2023.112428
Abstract

Activation of the Fanconi anemia (FA) pathway after treatment with mitomycin C (MMC) is essential for preventing chromosome translocations termed "radials." When replication forks stall at MMC-induced interstrand crosslinks (ICLs), the FA pathway is activated to orchestrate ICL unhooking and repair of the DNA break intermediates. However, in FA-deficient cells, how ICL-associated breaks are resolved in a manner that leads to radials is unclear. Here, we demonstrate that MMC-induced radials are dependent on DNA polymerase theta (POLθ)-mediated alternative end joining (A-EJ). Specifically, we show that radials observed in FANCD2-/- cells are dependent on POLθ and DNA ligase III and occur independently of classical non-homologous end joining. Furthermore, treatment of FANCD2-/- cells with POLθ inhibitors abolishes radials and leads to the accumulation of breaks co-localizing with common fragile sites. Uniformly, these observations implicate A-EJ in radial formation and provide mechanistic insights into the treatment of FA pathway-deficient cancers with POLθ inhibitors.

Keywords

CP: Molecular biology; FANCD2; Fanconi anemia; POLθ; RAD18; alternative end joining; common fragile sites; double-stranded break repair; radial chromosomes.

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