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Figure 6
(A) Constructs of etsrp:Cre and −3.5ubb:LOXP-EGFP-LOXP-mCherry (ubi:Switch). (B, C) Quantification of the pancreatic or ectopic β-cells with or without etsrp-positive mesodermal origin in control or etsrp morpholino (MO)-injected larvae at 3 dpf. *p=0.0169, ***p=0.0002, and ****p<0.0001 (Šidák’s multiple comparisons test); n=33 (control) and 30 (etsrp MO). Data are represented as the mean ± SEM. (D–E’’’) Representative confocal images of ectopic β-cells and etsrp-positive lineage-traced cells in control or etsrp MO-injected Tg(ins:Flag-NTR);Tg(ubi:Switch);Tg(etsrp:Cre) zebrafish larvae at 3 dpf after β-cell ablation by MTZ at 1–2 dpf, displaying β-cells in cyan with immunostaining for insulin and lineage-traced cells derived from etsrp-expressing mesodermal cells in red from the Cre-recombined ubi:Switch. The selected area in a dashed square in (E) is magnified in split (E’, E’’) and merged (E’’’) channels, respectively. Arrowheads point to ectopic β-cells derived from the mesoderm (E–E’’’). (F) Constructs of etsrp:Cre and ins:LOXP-mCherry-LOXP-Hsa.HIST1H2BJ-GFP (ins:CSH). (G–G’’’) Representative confocal images of ectopic β-cells derived from the etsrp-expressing lineage in etsrp MO-injected Tg(ins:Flag-NTR);Tg(ins:CSH);Tg(etsrp:Cre) zebrafish larvae at 3 dpf after β-cell ablation by MTZ at 1–2 dpf, displaying β-cells in magenta with immunostaining for insulin and lineage-traced cells derived from etsrp-expressing mesodermal cells in nuclear green from the Cre-recombined ins:CSH. The selected area in a dashed square in (G) is magnified in split (G’ and G’’) and merged (G’’’) channels, respectively. Scale bars = 20 μm (D, E, and G) or 10 μm (E’–E’’’ and G’–G’’’). Anatomical axes: D (dorsal), V (ventral), A (anterior), and P (posterior).
The ectopic β-cells derive from the etsrp-expressing mesodermal lineage in etsrp morphants.