Fig 3

Fig 3

(A-F) In vivo time course analysis of eGFP reporter expression during fin regeneration in Tg(2P-EIand1:eGFP) (n = 12). (A-B) At 2dpa and 3dpa, reporter expression is brightly observed only in the interray tissue of Tg(2P-EIand1:eGFP). Yellow arrowheads indicate location of fin ray tissue. Yellow dotted line delineates amputation plane. (C-D) At 4dpa and 7dpa, fin ray-specific reporter expression occurs along the proximal-distal axis and is as equally bright as that of interray expression in Tg(2P-EIand1:eGFP). (E-F) Fin ray-specific reporter expression becomes distally restricted in Tg(2P-EIand1:eGFP). (G-K) Immunostaining for eGFP in Tg(2P-EIand1:eGFP) on consecutive transverse cryosections of 4dpa fin regenerate. (G) In the most distal region of the regenerate, reporter expression faintly occurs in the basal epithelial layer (pink arrowheads) surrounding the hemirays. The fin ray and interray are indicated by white brackets. (H-K) As sections progress proximally, reporter expression within the basal epithelial layer (pink arrowheads) is restricted towards the interray region. Reporter expression within the mesenchymal tissue is indicated by yellow arrowheads. (I-K) Reporter expression within basal epithelial layer is absent in middle regions of hemirays and overlaps with mesenchymal-specific expression in regions of hemirays that are closer to interrays (indicated by dotted yellow box in Panel K). Pink stars indicate autofluorescence from blood vessels. Double fluorescence in situ hybridization (n = 8) on longitudinal sections (proximal to the left and distal to the right hand sides of the panels) of 3dpa fin regenerate for (L) and1 and (L’) eGFP of Tg(2P-EIand1:eGFP). (L”) Merge with DAPI staining of cell nuclei. fr: fin ray, ir: interray, m: mesenchyme; bel: basal epithelial layer; e: epithelium. n = # of fish of which fins were sectioned and on which given experiment was performed. Scale bars: A = 100μm, B-F = 200μm, G-K = 50μm, L-L” = 50μm.