Extended Data Fig. 4: Disruption of RAD51 filament by PARPi-induced PARP1 retention potentiated by PARPi potency.
From: BRCA2 prevents PARPi-mediated PARP1 retention to protect RAD51 filaments
(a-b) Representative smFRET trajectory and normalized FRET histogram of RAD51 only (first panel), RAD51 with PARP1 + talazoparib (second panel), RAD51 with PARP1 + saruparib (third panel), RAD51 with PARP1 + olaparib (fourth panel) and finally RAD51 with PARP1 + veliparib (fifth panel). All four panels with PARPi show three distinct states (PR + N, IE, E), however, the shift in the population distribution is worth noting where talazoparib and saruparib causes maximum disruption to the RAD51 filament followed by olaparib and then little to no disruption by veliparib. (c) Quantification of the effect of different PARPi to the RAD51 filament stability. Lanes: 1: RAD51 only, 2: talazoparib, 3: saruparib (n = 433), 4: olaparib (n = 460) and 5: veliparib (n = 450). Data shown is mean ± s.d (r = 2). (d) Schematic and western blot showing bead-capture experiment to measure binding of RAD51 to 167 nucleotide 3′ tailed DNA pre-incubated with PARP1 ± NAD+ ± saruparib/olaparib/veliparib. The number of analyzed molecules and replicates are denoted by n and r, respectively. Cartoons were created in BioRender. Lahiri, S. (2025) https://BioRender.com/g65f931. [RAD51] = 0.4 µM | [ATP] = 2 mM [PARP1]smFRET = 0.4 µM | NAD+ = 1 mM | [PARPi] = talazoparib (0.1 µM), saruparib (0.1 µM), olaparib (10 µM) and veliparib (100 µM).
