| First Author | Ronson GE | Year | 2023 |
| Journal | Nat Commun | Volume | 14 |
| Issue | 1 | Pages | 7834 |
| PubMed ID | 38030626 | Mgi Jnum | J:343250 |
| Mgi Id | MGI:7563425 | Doi | 10.1038/s41467-023-43677-2 |
| Citation | Ronson GE, et al. (2023) Mechanisms of synthetic lethality between BRCA1/2 and 53BP1 deficiencies and DNA polymerase theta targeting. Nat Commun 14(1):7834 |
| abstractText | A synthetic lethal relationship exists between disruption of polymerase theta (Poltheta), and loss of either 53BP1 or homologous recombination (HR) proteins, including BRCA1; however, the mechanistic basis of these observations are unclear. Here we reveal two distinct mechanisms of Poltheta synthetic lethality, identifying dual influences of 1) whether Poltheta is lost or inhibited, and 2) the underlying susceptible genotype. Firstly, we find that the sensitivity of BRCA1/2- and 53BP1-deficient cells to Poltheta loss, and 53BP1-deficient cells to Poltheta inhibition (ART558) requires RAD52, and appropriate reduction of RAD52 can ameliorate these phenotypes. We show that in the absence of Poltheta, RAD52 accumulations suppress ssDNA gap-filling in G2/M and encourage MRE11 nuclease accumulation. In contrast, the survival of BRCA1-deficient cells treated with Poltheta inhibitor are not restored by RAD52 suppression, and ssDNA gap-filling is prevented by the chemically inhibited polymerase itself. These data define an additional role for Poltheta, reveal the mechanism underlying synthetic lethality between 53BP1, BRCA1/2 and Poltheta loss, and indicate genotype-dependent Poltheta inhibitor mechanisms. |
