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Figure 5. A,B: Xenopus laevis matrix metalloproteinase 28 (XMMP-28) protein expression during hindlimb regeneration (A) or Wallerian degeneration (B). A: Blastemas of stage 53 Xenopus hindlimbs were stained for XMMP-28 (green) and acetylated tubulin (red) at 3, 7, and 13 days after amputation or XMMP-28 (Green) and MAG (Red) at 17 days after amputation. Images of blastema were collected by confocal microscopy, whereas limb renervation images were collected using epifluorescence microscopy. Nuclei were counterstained with DAPI. B: Merged images of stage 57 Xenopus hindlimbs stained for XMMP-28 (green) and either acetylated tubulin (middle row, red) or MAG (bottom row, red). Nuclei were counterstained with 4′,6-diamidine-2-phenylidole-dihydrochloride (DAPI). Coexpression is indicated by yellow staining. Arrows indicate XMMP-28–positive nerves. Arrowhead indicates MAG–positive glial cells. Green fluorescence in the epidermis of limbs was variable, not consistent at any time points, and present in negative controls (isotype and no primary antibody controls; data not shown). Potential contribution of MMP-28 expression to epidermal staining was, therefore, not resolved. Epidermal variability was not found to be consistent at any time points. Images are representative of limbs from two independent experiments (three limbs per experiment). Scale bars = 50 μm. |