Figure 5.

NECs utilize more origins than NPs to complete DNA replication

(A) The scheme shows the sequential incorporation of IdU (red) and CldU (green) in a fired origin. Representative images of DNA fiber spreads derived from WT embryos at E10.5 and E14.5 are shown. White arrowheads indicate structures of DNA replication origins activated during the first pulse.

(B and C) Schematic representation of DNA fiber structures showing two adjacent DNA replication origins. The distance between two adjacent origins is marked as the interorigin distance (IOD) (B). Interorigin distances in DNA fibers were quantified and are depicted in the graph (C). Data were obtained from two independent experiments (∼30 pairs of consecutive origins/condition; five embryos per condition in each experiment). Mean ± SEM. ^∗p ≤ 0.05; Mann-Whitney.

(D) Vibratome sections of embryo brains at E10.5 and E14.5 were subjected to a pre-extraction protocol and immunofluorescent staining with antibodies against MCM2 (red) and EdU (green). White arrowheads point to cells in G1 identified as MCM2⁺EdU⁻. DNA was stained with DAPI (blue).

(E) The graph shows the intensity of MCM2 per cell in vibratome sections. The line represents the mean value for each group. Data from one representative experiment are presented in the graph (∼100 cells/condition). ^∗∗p ≤ 0.01; Mann-Whitney. Two more independent experiments were performed and the data are presented in Figure S3C. Scale bars: 10 μm.