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Fig. 2. Expression pattern of GFP in Mprx1-GFP transgenic Xenopus. (A–G) are F0 and (I–M) are F2 animals of line 1. (A, B) Lateral view of a stage 53 tadpole shows GFP expression in the forelimb bud (arrow) and hindlimb bud (arrowhead). (B) Bright-field image of panel A. (C, D) High power views of fore- and hindlimb buds of panel A, respectively. (E) Lateral view of limb bud blastema of a stage 54 tadpole shows uniform GFP expression in the blastema. Lines indicate the amputation plane. (F, G) Dorsal view of froglet forelimb blastema shows GFP expression in the blastema and proximal region (bracket). (G) Bright-field image of panel F. (H) Dorsal views of froglet blastema of wild-type animal. (I–M) Longitudinal sections of amputated froglet forelimbs. (I) In the intact limb, GFP was detectable in the periosteum and ectoderm. (J) At 2 days, extensive up-regulation was observed in the mesodermal region. A high-power view of the boxed region (L) shows a number of fibroblastic cells expressing GFP. Yellow staining of the right distal region (asterisk in panel J) is autofluorescence of the tissue debris. (K) A limb stump at 4 days after amputation. (M) A high-power view of the boxed region in panel K shows that the majority of mesenchymal cells in the early blastema expressed GFP. Scale bars: in panel B, 2 mm for panels A, B; in panels I, J, K 200 μm. |
