Removing the Mcm4 proximal NSD allows advanced firing of late origins in an unperturbed S phase. Yeast cells were synchronized in G1 phase and released into YPD containing 0.5 mM EdU for 25 min at 30°C. (A) Replication profiles of Chromosome IV for WT and Mcm4 NSD mutants. Red arrows indicate late origins that are inactive in the wild-type cells but fire in the triple mutant in HU as in Figure 2. (B) Plots comparing the peak height between duplicate samples of mutant strains (red and orange) to a wild-type reference (blue). Data also presented in Supplemental Figure S2. Peak heights for each sample were scaled so that the 90% quantile is equal to 1.0.
