Fig. 1

sox32-expressing endoderm progenitors emerge from a population of tbxta/tbx16-positive progenitors

(A) Time series showing maximum intensity projections (MIP) of RNAscope for tbxta, tbx16 and sox32. Dashed white line, embryo margin; arrowhead, dorsal.

(B) Z-reconstruction through the lateral regions of the embryos in (A). Dashed line marks boundary between embryo and YSL. Colors as in (A); nuclei marked with DAPI (gray).

(C) Density scatter plots showing nuclear intensity staining for tbxta and tbx16 for all cells pooled from four embryos for each time point.

(D) As in (C), but showing cells with elevated sox32 expression (defined as log[nuclear sox32 intensity] > 8.5) in the context of all cells (gray). The density scale in (C) and (D) is normalized to a maximum density of 1.0 for each plot.

(E) Scatter plots from (D) colored to show the position of the closest point at the margin of the embryo from dorsal (0 degrees: red) to ventral (180 degrees: blue). Lateral regions on both sides of each embryo are given the same positional value. Nuclei beyond the margin are marked in black.

Populations of cells in (D) and (E) composed predominantly of black cells or red cells are YSL and dorsal forerunner (DFCs), respectively. The remaining cells are endodermal progenitors (Endo). See also Figure S1 Scale bars: 250 μm (A), 100 μm (B).