Figure 1—figure supplement 1.

TIE:EGFP zebrafish enhancer reporter is inducible and specific.

(A) TIE:EGFP reporter is induced upon electroporation with ubi:caSMAD2 and ubi:caSMAD3 in adult zebrafish flank skin. Ubi:BFP was used as a control for varying electroporation efficiency. TIE:EGFP intensity/BFP area was quantified (right). Two-tailed unpaired Welch’s t-test was used to calculate significance. Representative images shown. n=8 fish per condition. (B) TIE:EGFP embryos treated at 1 day post fertilization for 24 hr with E3 (zebrafish water), DMSO (vehicle control), 50 µM or 100 µM TGFb inhibitor SB431542. TIE:EGFP channel (top) and white light (bottom). Representative images shown. Scale bars represent 500 µm. (C) In situ hybridization (ISH) was performed probing for GFP in embryos treated with DMSO (n=26), 50 µM (n=30), or 100 µM (n=31) TGFb inhibitor SB431542 for 24 hr starting at 1 day post fertilization. Embryos were grouped into three qualitative groups based on GFP intensity: low, medium, and high, and the percentage of embryos in each are graphed below. (D) Representative image of mitfa:mCherry⁺ zebrafish fin melanocytes expressing TIE:EGFP. The uppermost EGFP⁺ region not overlapping with mCherry signal is residual spinal expression of TIE:EGFP. (E) Early melanomas, indicated by arrowheads, do not express TIE:EGFP. The EGFP⁺ region not overlapping with mCherry signal is residual brain expression of TIE:EGFP. Representative images shown. Illustrated fish diagrams in (A, D, E) created with BioRender.com, and published using a CC BY-NC-ND license with permission.