Fig. 5. Replication origin selection in the DHFR locus in CHOC 400 G1 nuclei is independent of Xenopus Mcm proteins. Intact CHOC 400 pre-ODP (2 hours in G1; squares and diamonds) or post-ODP (6 hours in G1; circles and triangles) nuclei were introduced into mock-depleted (A; squares and circles), Mcm3-depleted (A; diamonds and triangles), control untreated (B; squares and circles) or geminin-supplemented (B; diamonds and triangles) Xenopus egg extracts. Specificity of initiation in the DHFR locus was determined by the ELFH assay as described in Materials and Methods.