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Fig. S2
Wnt/β-catenin signaling is active in cells of the distal-most scarcely proliferative blastema, which retain their relative localization during regenerative growth, plus in different domains of the proximal blastema, related to figure 2.
(A) Reporter activity in proximally located blastemal regions is robustly observed in 6xTCF:dGFP transgenic regenerates (big white arrowhead), but is detected in 7xTCF:mCherry transgenic regenerates only in a minority of samples after prolonged staining (big white arrowhead, 1/8 regenerates).
(B) axin2 expression is strongly detected in the distal blastema (arrow) plus weakly in the lateral blastema containing the actinotrichia-forming cells (arrowhead) and the (pre)osteoblasts (asterisk). 7
(C) aldh1a2 (blue) co-localize with mCherry (brown) transcripts in the distal-most blastema in 7xTCF:mCherry transgenic regenerates. Note that samples were stained for mCherry expression only shortly, so that only the strongest expression domain in the distal blastema was detected.
(D) mCherry transcripts (brown) are detected distally to egfp (blue) transcripts in 7xTCF:mCherry; her4.3:EGFP double transgenic regenerates.
(E) mCherry fluorescence is detected distally to the EGFP fluorescence-positive proximal blastema (asterisk) in 7xTCF:mCherry; her4.3:EGFP double transgenic regenerates. Optical section through the center of a whole mount blastema is shown.
(F) 7xTCF:mCherry reporter activity is detected in the Pcna-negative distal-most blastema. Optical section through the center of a whole mount blastema stained for mCherry transcripts (short staining) and Pcna protein is shown.
(G-H) Kaede fluorescence (G) and transcripts (H) in 7xTCF:3xKaede transgenic regenerates.
(I-J) Kaede-positive Wnt-receiving cells located in the distal-most row of mesenchymal cells of a 3 day-old 7xTCF:3xKaede transgenic blastema were photoconverted from green to red fluorescence and traced for two consecutive days. Cells containing the converted Kaede (red) were still detected in the distal-most cell row 24 hours and 48 hours post conversion (arrowheads in I) despite the substantial regenerative growth that occurred in these fins (J).
(A-J) Small arrowheads: amputation plane. Scale bars: whole mounts, 200 μm (A, G-H, J) and 100 μm (C-F, I); sections, 100 μm.