DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells

Tyler, J. K.; Fowler, F. C.; Peart, C.; Chen, B.-R.; Sleckman, B.; Zolnerowich, N.; Nussenzweig, A.; Pavani, R.; Wu, W.; Paiano, j.

doi:10.1101/2021.10.21.465258

bioRxiv · 10.1101/2021.10.21.465258

DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells

Tyler, J. K.·Fowler, F. C.·Peart, C.·Chen, B.-R.·Sleckman, B.·Zolnerowich, N.·Nussenzweig, A.·Pavani, R.·Wu, W.·Paiano, j.

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Abstract

DNA double-strand break (DSB) repair by homologous recombination is confined to the S and G2 phases of the cell cycle partly due to 53BP1 antagonizing DNA end resection in G1 phase and non-cycling quiescent (G0) cells where DSBs are predominately repaired by non-homologous end joining (NHEJ). Unexpectedly, we uncovered extensive MRE11- and CtIP-dependent DNA end resection at DSBs in G0 mammalian cells. A whole genome CRISPR/Cas9 screen revealed the DNA-dependent kinase (DNA-PK) complex as a key factor in promoting DNA end resection in G0 cells. In agreement, depletion of FBXL12, which promotes ubiquitylation and removal of the KU70/KU80 subunits of DNA-PK from DSBs, promotes even more extensive resection in G0 cells. In contrast, a requirement for DNA-PK in promoting DNA end resection in proliferating cells at the G1 or G2 phase of the cell cycle was not observed. Our findings establish that DNA-PK uniquely promotes DNA end resection in G0, but not in G1 or G2 phase cells, and has important implications for DNA DSB repair in quiescent cells.

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Tyler, J. K., Fowler, F. C., Peart, C., Chen, B.-R., Sleckman, B., Zolnerowich, N., Nussenzweig, A., Pavani, R., Wu, W., Paiano, j.. 2021-10-21. DNA-PK Promotes DNA End Resection at DNA Double Strand Breaks in G0 cells. https://doi.org/10.1101/2021.10.21.465258

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