FIGURE 3 ∣.

Pulse-Chace experiments using EdU. (A) Uninjured animals were incubated with EdU and dividing cells were detected. Most dividing cells were observed in the gut epithelium. (B) Uninjured animals were incubated with EdU, then cut and allowed to regenerate for 48 h. There were very few labeled cells in anterior regenerating tissue (arrowhead), but many labeled cells in the gut epithelium. (C) Animals were labeled with EdU at 3 days post-amputation (dpa) and dividing cells were detected. Labeled cells were detected in and around the epithelium of regenerating tissues. (D) Animals were labeled with EdU at 3 dpa and allowed to regenerate for 24 h. Labeled cells appeared to remain in the anterior portion of the regenerating tissue after 24 h. The mass of labeled cells enlarged, and the regenerating blastema appeared to start forming a small proboscis (arrow). The left side is the anterior portion of regenerating tissues in all panels. Scale bar = 0.3 mm and all samples are 3–4 mm in size. Acquired microscopic data were composed into a single image for each sample. ge, gut epithelium; re, regenerating epithelium.