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Figure 6. Expression of XlSALL4 during Xenopus hindlimb regeneration at the regeneration-competent and regeneration-incompetent stages. A: Whole-mount in situ hybridization (WISH) using anti-sense XlSALL4 probe at the stages (stage 53, 55, 57) and at the times after amputation (t = 0 control, 1-day, 3-days, 5-days, and 7-days) as indicated. Amputations were through the zeugopodia just distal to the knee joint. Dorsal views with the posterior side (pigmented) of the limb up and proximal to the left. Magnifications are variable to fit different size limbs into constant boxes. B: Expression of XlSALL4 in stage 53 amputated hindlimb stumps 1 day after amputation. End-on WISH images showing polar expression in distal amputated stump. The upper row shows three examples of the distal limb stump 1 day after amputation, while the bottom shows three controls fixed for WISH immediately after amputation (t = 0). Note intense XlSALL4 expression primarily in the posterior side of the distal limb stump 1 day after amputation compared with the t = 0 controls. By 3 days after amputation XlSALL4 expression is uniform throughout the mesenchyme of the blastema (data not shown). Anterior–posterior and ventral–dorsal limb axes are shown. All magnifications are the same. |
