Fig. 1: WASp is a DNA stress-response protein.

a Proximity ligation assay (PLA). Confocal immunofluorescence (IF) microscopy showing a representative set of collapsed composite IF images from a z-stack of ~30-40 images acquired per optical field. Shown are the PLA signals between the indicated interacting proteins induced by the indicated genotoxins or no damage control in human T and B cells, along with their corresponding PLA statistics in box-and-whisker plots (whiskers @10–90%, horizontal bar denotes median, “+” denotes mean). In both panels, unpaired, two-tailed, Mann-Whitney nonparametric p values ****<0.0001, n = 150 cells/condition. Scale bar: 3 μm. b In situ analysis of protein interactions at replication forks (SIRF). Right, Representative z-stack collapsed composite confocal IF images showing SIRF signals between 5-ethynyl-2’-deoxyuridine (EdU)-labeled nascent DNA and the indicated protein in steady-state (no damage) or after HU- or CPT-induced DNA perturbation, along with their corresponding statistics (n = 100 cells). Left, representative SIRF images of positive and negative controls (ctrl), under replicative stress or no stress/damage. Statistical details as per a. Scale bar: 2 μm. c Isolation of proteins on nascent DNA (iPOND). Left, schematic of nascent DNA labeling, in which red line denotes DNA labelled with EdU, followed by black line denoting chase into media containing either hydroxyurea (replication stressor) or thymidine (control for true replication proteins that will not enrich in this sample due to EdU displacement). Middle, shows Western blots of input and iPOND purified proteins under indicated conditions, including no EdU sample (no-click negative control). Right, bar graphs depict gel densitometric quantitation of iPOND/Western blot signals normalized to their respective inputs. n = 3, +SEM. Mann-Whitney unpaired two-tailed nonparametric p-value *<0.01. Source data are provided as a Source Data file.