Fig. 3.

Stable 53BP1-chromatin interactions require DYNLL1-dependent and -independent oligomerization modes. a Representative FRAP series. Example shows recovery of WT mC2-f53BP1. Bottom right corner shows magnified region of bleached area. All FRAP experiments were performed in 53BP1^-/- MCF-7 cells stably expressing the indicated mC2-f53BP1 fragments. b Mean recovery from a single FRAP experiment in cells expressing mC2-f53BP1 (n = 8), mC2-f53BP1^LC8m (n = 9), or mC2-f53BP1^ODm (n = 10), mean ± SEM. Data, representative of n = 3 independent experiments. c Time for half-recovery of maximum final fluorescence for IRIF in individual cell expressing mClover2-WT (n = 26), mC2-f53BP1^LC8m (n = 26), or mC2-f53BP1^ODm (n = 25) proteins. Mean ± CI (95%). P-values, Mann–Whitney U test. d Curves of best fit for three aggregated experiments. Data points represent the mean of n ≤ 25 determinations. e Calculated initial rates (dy/dt) for the curves generated in (d). f Purified Smt3-His₆-tagged DYNLL1 was incubated with Smt3-His₆-tagged 53BP1^ODm or 53BP1^LC8m/ODm fragments (a.a. 1131–1292) as indicated. 1 μg of 53BP1 was added to each reaction with increasing concentrations of DYNLL1. Molar ratios of DYNLL1:53BP1 from left to right; 1:4, 1:2, 1:1, 2:1, 4:1. Samples were fractionated by native (8%) or denaturing (12%) PAGE and stained with Coomassie Brilliant Blue. Data, representative of n = 2 independent experiments