Fig. 6

a Schematic illustration of PGC isolation and RNA-seq in sibling and smad1-cKO embryos. b Expression levels of PGC-specific genes in sibling and smad1-cKO PGCs. c Volcano plots showing DEGs between smad1-cKO and sibling PGCs at the indicated stages. Red and blue dots indicated upregulated and downregulated genes, respectively. d Expression of DEGs between the 1 dpf cKO and sibling PGCs at the 75% epiboly and 1 dpf stages (left heatmaps) and functional enrichment of upregulated genes in smad1-cKO PGCs at 1 dpf (right, bubble plot). e Detection of DNA damage in PGCs (Ddx4, green) via γH2A immunostaining (magenta) in sibling and smad1-cKO embryos at the 5-somite stage. Red and white dotted circles indicated γH2A-positive and -negative PGCs, respectively. Right, quantification of nuclear γH2A intensities normalized to cytoplasmic levels. Each dot represented one PGC. f Immunostaining of pChk1 (magenta) in sibling and smad1-cKO embryos at the bud stage. PGCs were labeled by Ddx4 (green). Red and white circles indicated pChk1-positive and -negative PGCs, respectively. Right, quantification of nuclear pChk1 intensities normalized to cytoplasmic levels. Each dot represented one PGC. g Representative images (left) and quantification of PGCs (right) in the gonad regions of sibling and smad1-cKO embryos treated with DMSO or ATR inhibitor (AZ20) from the sphere stage to the 1 or 2 dpf. PGCs were labeled with kop:Eos (green). Each dot represented one embryo. Error bars represented SD with the mean indicated by the center line in (e–g). Statistical significance was determined by a two-sided Student’s t-test. Nc, number of observed PGCs; Ne, number of observed embryos. Source data are provided as a Source Data file.