Fig. 4

Fig. 4

A UMAP plots of cxcl12a, hand2, and pax2a. Cells are colored by scaled expression values using lower and upper 1%-quantiles as boundaries. B, C Snapshots of time-lapse movie (Supplementary Movie 1) showing drl:EGFP with primordial germ cell (PGC) marker mCherry-f′-nos3′UTR, with 3D renderings at 60% epiboly, 1 ss, and 10 ss (B) and maximum intensity Mercator projections for the same time points (C). The PGCs migrate from four different clusters during gastrulation into two bilateral clusters during somitogenesis (boxed regions). Note the sparse (lost) PGCs located within the endoderm (asterisks). Animal side is for 60% epiboly to the top, anterior for 1 ss and 10 ss (B) to the top and (C) to the left. D Imaging of hand2:EGFP with mCherry-f′-nos3′UTR showing a dorsal view at 24 hpf: the PGC clusters fall completely within the hand2:EGFP domain. The outlines of the yolk extension are highlighted. E Segmented 3D rendering of a hand2:EGFP; mCherry-f′-nos3′UTR double-positive embryo stained with anti-Pax2a (yellow) and DAPI (blue) at 28 hpf. F A schematic transverse section of a 24 hpf embryo showing two bilateral PGC clusters (magenta) lateral of the developing gut, ventral-lateral of the Pax2a-positive developing pronephros (yellow) within the cxcl12a-high hand2-positive LPM/coelomic epithelium (green). Scale bar D, E 250 μm.