Inhibition of Bmp activity prevents pectoral fin development but does not promote cell apoptosis at earlier stages of pharyngeal cartilage development, related to Figure 4. (A) Effect of inhibition of Bmp signaling on pectoral fin development. Wild-type (WT) embryos treated with 10 M of the Bmp inhibitor dorsomorphin or Tg(hsp70l:dnBmpr-GFP) transgenic embryos heat-shocked for the expression of the dominant negative Bmp receptor showed shorter and smaller pectoral fins (indicated by arrowheads) at 80 hpf. The embryos were dorsally viewed with anterior to the left. The third column showed pectoral fin cartilages stained with Alcian blue. Heat-shocked Tg(hsp70l:dnBmpr-GFP) transgenic embryos exhibited a reduction of endoskeletal disc and cleithrum cartilages with missing of the scapulocoracoid cartilage (indicated by arrowheads). Scale bars, 200 µm for the first two columns and 100 µm for right column. (B) Effect of inhibition of Bmp signaling on cell apoptosis. Tg(fli1:GFP) transgenic embryos treated with 10 M of the Bmp inhibitor dorsomorphin were subjected to TUNEL assay at 42 hpf. Representative confocal microscopic images of TUNEL-positive (red) chondrogenic progenitors (green) in the first and second pharyngeal arches (PA) were shown. Scale bar, 20 µm.
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