FIGURE 4: Expression of full-length NSR1 is required to greatly exacerbate G4-induced recombination in TOP1Y727F nsr1Δ and TOP1Y740Stop nsr1Δ strains. (A-D) Recombination rates of top1Δ nsr1Δ (A), TOP1S733E nsr1Δ (B), TOP1Y727F nsr1Δ (C), or TOP1Y740STOP nsr1Δ (D) yeast strains expressing the indicated Nsr1 constructs. Rates are listed above their respective bars and are considered statistically significantly different if their 95% confidence intervals (shown as error bars) do not overlap. N-term = pADH1-Nterm Nsr1, C-term = pADH1-Cterm Nsr1, NSR1 FL = pADH1-Nsr1, and vector = pRS426. (E, F) Co-immunoprecipitation (co-IP) experiments conducted with vtc4Δ yeast strains expressing 3XFLAG-tagged Top1 proteins and either 6X-HA-tagged full-length Nsr1 (E) or NsrΔRGG (F). Pull down was carried out with αFLAG antibody-coated agarose beads. Blots were probed with either αFLAG or αHA antibodies. Quantification of binding was calculated by dividing FLAG IP pixel intensities from HA-IP pixel intensities and presented in graphs in Figure S10.