F. support DNA replication. These findings indicate that Mcm10 is localized to replication initiation sites by directly binding MCM through the Mcm10 C terminus. strains and ?and44was as in Ref. 13. Open in a separate window FIGURE 3. The C terminus of Mcm6 is not required for Mcm10 recruitment, or DNA replication initiation. marks nicked plasmid products that are labeled in a replication-independent manner. Open in a separate window FIGURE 4. Mcm10 is recruited via two modes that require direct binding to MCM. was carried out with extract depleted of endogenous Mcm10 and supplemented with buffer (marks nicked plasmid products that are labeled in a replication-independent manner. were separated by SDS-PAGE and analyzed by Western blotting with antibodies raised against Rad53 or Mcm7 as indicated. Rad53 becomes activated toward the end of S-phase specifically in cells. and and washed once with phosphate-buffered saline before freezing and storage at ?80 C until use. All bacterial cells were lysed in the relevant lysis buffer supplemented with 0.5 mg/ml lysozyme (Sigma) for 30 min on ice, followed by sonication. Lysate was clarified by centrifugation at 23,600 W303 genomic DNA template)BamHIBamHIpMD84pET28afor 10 min at 4 C. To precipitate Mcm10, the supernatant was incubated for 1 h with Ni-NTA beads washed with buffer MCM +500 mm potassium glutamate, with occasional mixing. Beads were washed three times with buffer MCM +500 mm potassium glutamate, and bound proteins were separated by SDS-PAGE and visualized with InstantBlue protein stain (Expedeon). Double Hexamer Binding Assays with Purified Mcm10 MCM was loaded onto 1-kb biotinylated AR305 DNA templates as described (2), washed twice with buffer MCM +300 mm potassium glutamate, and incubated for 10 min at 30 C with purified Mcm10 in a binding mix that contained 25 mm Hepes, 10% glycerol, 5 mm magnesium acetate, 0.02% Nonidet P-40-S, 300 mm potassium glutamate, 1 mm DTT, 1 mm ATP, and 0.2 mg/ml poly(dIdC)poly(dIdC). Binding mixes were washed twice with buffer MCM +300 mm potassium glutamate, and DNA was photocleaved off beads as described (14) and analyzed by SDS-PAGE and silver staining. Subunit Pulldown Assays with Bacterially Expressed Mcm10 Anti-T7 antibody beads (Abcam) were pre-bound to bacterially expressed, purified Mcm10 in buffer MCM + 100 mm potassium glutamate and washed one time with buffer MCM + 500 mm potassium glutamate. Purified MCM subunits were diluted into buffer MCM + 500 mm potassium glutamate and incubated with bead-bound Mcm10, or anti-T7 antibody beads alone, for 1.5 h on ice with occasional mixing. Binding reactions were washed three times with buffer MCM + 500 mm potassium glutamate before bound proteins were separated by SDS-PAGE and visualized with InstantBlue protein stain 3-methoxy Tyramine HCl (Expedeon). Pulldown Assays with Reticulocyte Lysate-expressed Mcm10 100 ng of plasmid DNA was added to 20 l of reticulocyte lysate (Promega) with 10 Ci of [35S]methionine (PerkinElmer) to a final volume of 25 l. Protein was expressed for 1.5 h at 30 C, 100 l of buffer MCM + 500 Rabbit polyclonal to POLDIP2 mm potassium glutamate was added, and the sample was divided between 5 l of amylose resin pre-bound to either MBP-Mcm6C or MBP. Reactions were incubated on ice for 3-methoxy Tyramine HCl 1.5 h before washing 3-methoxy Tyramine HCl three times with buffer MCM + 500 mm potassium glutamate. Bound proteins were separated by SDS-PAGE and visualized by autoradiography. Mcm10 and Cdt1 Competition Assays Stoichiometric MCMCdt1 complexes purified from budding yeast (14) were incubated in buffer MCM +500 mm potassium glutamate, with 2 mm ATPS and varying.