Fig. 4: Analysis of the DNA binding and helicase activities exhibited by MCM8-9 and MCM8IP.

a Representative gel of an electrophoretic mobility shift assay with a ssDNA plasmid (M13mp18, 100 ng per reaction) incubated with increasing amounts of recombinant MCM8-9 in the presence or absence of MCM8IP (50 nM). b Graphical representation of the percentage of ssDNA plasmid bound by recombinant MCM8-9 in the presence or absence of MCM8IP in electrophoretic mobility shift assays conducted as in (a). The mean ± SD of three or more independent experiments (n = 3–4) is presented. Statistical analysis was conducted using Student’s t-test (*p < 0.05, **p < 0.01, two-tailed). c Schematics of a DNA unwinding reaction conducted using a ³²P-labeled ssDNA oligo annealed to a ssDNA plasmid (M13mp18) in the presence of the indicated proteins (top panel). Representative autoradiograph of a DNA unwinding reaction conducted using the depicted DNA substrate in the presence or absence of ATP with purified MCM8-9 (100 nM), WT MCM8IP (50 nM), or RPA (222 nM), either alone or in combination (bottom panel). D—boiled DNA substrate control. d Graphical representation of the percentage of DNA unwinding in reactions conducted as in (c). The mean ± SD of three independent experiments is presented. Statistical analysis was conducted using one-way ANOVA (*p < 0.05, ***p < 0.001, ****p < 0.0001). e Representative autoradiograph of the ATP-dependent DNA unwinding reaction shown in (c) conducted with increasing concentrations of MCM8-9 alone (lanes b–d) or at a fixed MCM8-9 concentration (100 nM) in the presence of WT MCM8IP, MBM #1 or MBM #2 proteins (each at 50 nM, lanes e–g). f Graphical representation of the percentage of DNA unwinding in reactions conducted as in (e) in the presence of ATP. The mean ± SD of at least three independent experiments (n = 3–5) is presented. Statistical analysis was conducted as in (d) (****p < 0.0001).