Replication origin activity of the Mcm4-Prkdc intergenic region in chicken cells. A. Schematic illustration of the Mcm4-Prkdc intergenic region. The black boxes and the arrows denote the transcriptional start sites of both genes. The positions of primer pairs used in the PCR analysis are shown below. The scale at the top is in kilobases. B. Nascent strand abundance assay. For quantification, real-time PCR was performed using the primer pairs indicated at the bottom. The columns show the average abundance of the corresponding sequences in nascent strand preparations of BM2 (black columns) or HD11 (white columns) cells relative to the sequences amplified with the -0.5 kb primer pair. Error bars mark the standard deviations. C. Nascent strand abundance analysis of the Mcm4 promoter region using wild-type (black columns) or c-myb deficient (white columns) DT40 cells.