Fig 1

(A) Schematic representation of transgenic reporter constructs. GFP expression of four and1 reporter lines at 3dpf (B-E), 30dpf (F-I), 60dpf (J-M) and 90dpf (N-Q) showing fluorescent images merged onto bright field images. (B, B’, C, C’) confocal images (note: autofluorescence in the trunk tissue in C). Note: obtaining exactly the same plane of focus in the two transgenic lines is difficult; however, these images are simply to represent both transgenic lines have eGFP-positive ectodermal and mesenchymal cells. (B’, C’) 2x higher magnification on region boxed in red in panels B and C, respectively, showing the more elongated mesenchymal cells (pink arrowheads) in contrast to the hexagonally-shaped ectodermal cells (white arrowheads). (B, F, J, N) Tg(2Pand1:eGFP) (n = 5) expression in the ectoderm and fin ray mesenchyme fades after 30dpf. (C, G, K, O) Tg(2P-EIand1:eGFP) (n = 2) expression in the ectoderm and fin ray mesenchyme persists after 30dpf. (D, H, L, P) Tg(epi.and1-βG:eGFP) (n = 2) expression in the ectoderm is absent at 30dpf and onward; and (E, I, M, Q) Tg(2PΔepi.and1:eGFP) (n = 2) expression in the fin ray mesenchyme persists. Yellow arrowheads indicate fin ray-specific reporter expression. n = # of lines, ~25 fish/line. Scale bars = 200μm.