Dnmt1 depletion leads to reduced self-renewal of the progenitor pool. (A) OPT 3D reconstruction of the Six2-positive nephron progenitor niches and Six2 and pan-cytokeratin confocal images of Six2Cre;Dnmt1 HET and KO kidneys at E15.5. Scale bars, 300 and 50 µm, respectively. (B) OPT 3D reconstruction of the Six2-positive nephron progenitor niches and Six2 and pan-cytokeratin confocal images of HET and KO kidneys at E19.5. Scale bars, 400 and 50 µm, respectively. (C) Total number of niches at E15.5 and E19.5 using OPT analysis (n=8 and n=5, respectively). One-tailed P value. (D) Number of cells per niche, determined by confocal imaging (E15.5, HET: n=7, KO: n=8, and E19.5: n=5). One-tailed P value. (E) Quantification of BrdU-positive Six2Hi cells on E18.5 kidney sections (HET: n=5 and KO: n=4). (F) Quantification of BrdU-positive Six2Lo cells on E18.5 kidney sections (HET: n=5 and KO: n=4). (G) Estimated total progenitor cell number at E15.5 and E19.5 from niche number and cell number per niche (HET: n=7 and KO: n=5). HET, heterozygous; KO, knockout.