title: Experimentally induced metamorphosis in axolotls reduces regenerative rate and fidelity.
abstract: While most tetrapods are unable to regenerate severed body parts, amphibians display a remarkable ability to regenerate an array of structures. Frogs can regenerate appendages as larva, but they lose this ability around metamorphosis. In contrast, salamanders regenerate appendages as larva, juveniles, and adults. However, the extent to which fundamental traits (e.g., metamorphosis, body size, aging, etc.) restrict regenerative ability remains contentious. Here we utilize the ability of normally paedomorphic adult axolotls (Ambystoma mexicanum) to undergo induced metamorphosis by thyroxine exposure to test how metamorphosis and body size affects regeneration in age-matched paedomorphic and metamorphic individuals. We show that body size does not affect regeneration in adult axolotls, but metamorphosis causes a twofold reduction in regeneration rate, and lead to carpal and digit malformations. Furthermore, we find evidence that metamorphic blastemal cells may take longer to traverse the cell cycle and display a lower proliferative rate. This study identifies the axolotl as a powerful system to study how metamorphosis restricts regeneration independently of developmental stage, body size, and age; and more broadly how metamorphosis affects tissue-specific changes.
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: James R
authors: JR
authors: Monaghan
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: Adrian C
authors: AC
authors: Stier
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Florida Museum of Natural History University of Florida Gainesville Florida 32611 USA.
authors: François
authors: F
authors: Michonneau
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: Matthew D
authors: MD
authors: Smith
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: Bret
authors: B
authors: Pasch
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: Malcolm
authors: M
authors: Maden
authors: Department of Biology University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA; Nexus Biology Group University of Florida 223 Bartram Hall, P.O. Box 118525 Gainesville Florida 32610 USA.
authors: Ashley W
authors: AW
authors: Seifert
keywords: Axolotl; cell cycle; limb; metamorphosis; regeneration; salamander