(A) WISH for PE marker wt1 at 40 hpf and 54 hpf. Arrows indicate PE cells with wt1 transcripts.
(B) Lateral view of hearts showing GFP-labeled PE and epicardium in 46-hpf, 52-hpf, and 72-hpf larvae carrying the Tg(tcf21:NLS-EGFP) transgene. White arrow indicates the extracellular matrix bridge between AVC and the pericardial wall.
(C) Ventral view of hearts showing GFP-labeled PE and epicardium in 48-hpf and 72-hpf sibling or tet2/3DM larvae carrying the Tg(tcf21:NLS-EGFP) transgene. White arrows indicate tcf21+ PE and epicardial cells located on the heart. Yellow arrows indicate tcf21+ PE and epicardial cells located on the yolk sac. Graph indicates the total number of PE and epicardial cells in 48-hpf or 72-hpf sibling and tet2/3DM larvae and the number of PE and epicardial cells located on heart or yolk sac at 72-hpf sibling and tet2/3DM larvae.
(D) The PE migration defect is partially rescued by TET2 mRNA injection or 5-aza treatment. GFP-labeled PE and epicardium in 4-dpf sibling, tet2/3DM, and tet2/3DM injected with wild-type hTET2 mRNA, mutant hTET2 mRNA, or tet2/3DM exposed to 75 μM 5-aza larvae carrying the Tg(tcf21:NLS-EGFP) transgene.
Graph indicating the number of epicardial cells located on the heart at 4 dpf is shown. Scale bars: (A) 50 μm; (B–D) 100 μm. **p < 0.01; ***p < 0.001; ns indicates not significant. Data are presented as mean ± SD derived from at least three independent biological replicates.