Bmp pathway acts transiently on proepicardial cells. Optical section (1 z-plane) of an in vivo time-lapse imaging of an epi:GFP;BRE:KushabiraOrange (KuO) 55 hpf embryo during 5.5 h. GFP-labeled dorsal pericardium (DP) and proepicardial (PE) cells (green) and cells active for the Bmp pathway are in red. Arrowhead in frames 15–22 points to a KuO+ PE cell. HT, heart tube. Scale bar: 50 μm. Shown is a representative movie from ≥ 3 biological and ≥ 2 technical replicates.