XB-ART-57745Dev Biol January 1, 2021; 473 59-70.
Nutrient availability contributes to a graded refractory period for regeneration in Xenopus tropicalis.
Xenopus tadpoles are a unique model for regeneration in that they exhibit two distinct phases of age-specific regenerative competence. In Xenopus laevis, young tadpoles fully regenerate following major injuries such as tail transection, then transiently lose regenerative competence during the "refractory period" from stages 45-47. Regenerative competence is then regained in older tadpoles before being permanently lost during metamorphosis. Here we show that a similar refractory period exists in X. tropicalis. Notably, tadpoles lose regenerative competence gradually in X. tropicalis, with full regenerative competence lost at stage 47. We find that the refractory period coincides closely with depletion of maternal yolk stores and the onset of independent feeding, and so we hypothesized that it might be caused in part by nutrient stress. In support of this hypothesis, we find that cell proliferation declines throughout the tail as the refractory period approaches. When we block nutrient mobilization by inhibiting mTOR signaling, we find that tadpole growth and regeneration are reduced, while yolk stores persist. Finally, we are able to restore regenerative competence and cell proliferation during the refractory period by abundantly feeding tadpoles. Our study argues that nutrient stress contributes to lack of regenerative competence and introduces the X. tropicalis refractory period as a valuable new model for interrogating how metabolic constraints inform regeneration.
PubMed ID: 33484704
PMC ID: PMC8061425
Article link: Dev Biol
Species referenced: Xenopus tropicalis
Genes referenced: mtor vtga2 vtgb1
GO keywords: cell proliferation
References [+] :
Aztekin, Identification of a regeneration-organizing cell in the <i>Xenopus</i> tail. 2019, Pubmed, Xenbase