Figure 1

Morphogenesis of oral regeneration in Nematostella. F-actin stained with BODIPY FL phallacidin (Molecular Probes, Eugene, OR, USA) in all images. (A) Cut site on the aboral fragment of bisected polyp, 1 hour post amputation (hpa). Initial epithelial closure has occurred, but severing of the retractor muscles during bisection is evident. (B) Cut site 6 hpa. (C) Cut site 24 hpa. Relatively little morphological change is evident, although severed ends of retractor muscle have been repaired. (D) 48 hpa. Initiation of tentacle buds from outgrowths of the ectoderm and endoderm is evident. (E) 72 hpa. Outgrowth of the tentacles continues, including formation of musculature in the tentacular endoderm. Retractor muscles in the body column have reestablished connections with the oral disc. (F) 96 hpa. Major repatterning events of regeneration are complete, with reformation of the tentacles, mouth, and pharynx. Scale bars = 50 μm.