@article {Shimadae202101138, author = {Kenji Shimada and Monika Tsai-Pflugfelder and Niloofar Davoodi Vijeh Motlagh and Neda Delgoshaie and Jeannette Fuchs and Heinz Gut and Susan M Gasser}, title = {The stabilized Pol31{\textendash}Pol3 interface counteracts Pol32 ablation with differential effects on repair}, volume = {4}, number = {9}, elocation-id = {e202101138}, year = {2021}, doi = {10.26508/lsa.202101138}, publisher = {Life Science Alliance}, abstract = {DNA polymerase δ, which contains the catalytic subunit, Pol3, Pol31, and Pol32, contributes both to DNA replication and repair. The deletion of pol31 is lethal, and compromising the Pol3{\textendash}Pol31 interaction domains confers hypersensitivity to cold, hydroxyurea (HU), and methyl methanesulfonate, phenocopying pol32Δ. We have identified alanine-substitutions in pol31 that suppress these deficiencies in pol32Δ cells. We characterize two mutants, pol31-T415A and pol31-W417A, which map to a solvent-exposed loop that mediates Pol31{\textendash}Pol3 and Pol31{\textendash}Rev3 interactions. The pol31-T415A substitution compromises binding to the Pol3 CysB domain, whereas Pol31-W417A improves it. Importantly, loss of Pol32, such as pol31-T415A, leads to reduced Pol3 and Pol31 protein levels, which are restored by pol31-W417A. The mutations have differential effects on recovery from acute HU, break-induced replication and trans-lesion synthesis repair pathways. Unlike trans-lesion synthesis and growth on HU, the loss of break-induced replication in pol32Δ cells is not restored by pol31-W417A, highlighting pathway-specific roles for Pol32 in fork-related repair. Intriguingly, CHIP analyses of replication forks on HU showed that pol32Δ and pol31-T415A indirectly destabilize DNA pol α and pol ε at stalled forks.}, URL = {https://www.life-science-alliance.org/content/4/9/e202101138}, eprint = {https://www.life-science-alliance.org/content/4/9/e202101138.full.pdf}, journal = {Life Science Alliance} }