Figure 9

Global DNA replication stress impairs zebrafish embryogenesis

(A) Schematic representation of the experimental workflow. Danio rerio embryos were treated with aphidicolin, a DNA polymerase inhibitor, starting at 6 h postfertilization (hpf) to inhibit embryo-wide DNA replication during S-phase.

(B) Bright-field images of representative embryos collected at 26 hpf, shown with the chorion intact (top) and removed (bottom) (n = 10).

(C) To assess DNA synthesis and cell proliferation under replication stress, dechorionated embryos were immersed in EdU for 1 h during aphidicolin treatment, followed by fixation and OpenEMMU.

(D) Whole-mount imaging of depigmented and optically cleared embryos enabled the high-resolution visualization of proliferative activity (EdU incorporation) across embryonic tissues (n = 10). Confocal z stack images show EdU incorporation, phospho-Histone H3 (Ser10) staining (pHH3) for mitotic cells, and nuclear DNA labeling. Insets (d′–d″) highlight magnified views of the boxed regions. The dotted lines indicate the developing myotomes, which are forming into segmented blocks of muscle.