A young tadpole of an anuran amphibian can completely regenerate an amputated limb, and it exhibits an ontogenetic decline in the ability to regenerate its limbs. However, whether mesenchymal or epidermal tissue is responsible for this decrease of the capacity remains unclear. Moreover, little is known about the molecular interactions between these two tissues during regeneration. The results of this study showed that fgf-10 expression in the limb mesenchymal cells clearly corresponds to the regenerative capacity and that fgf-10 and fgf-8 are synergistically reexpressed in regenerating blastemas. However, neither fgf-10 nor fgf-8 is reexpressed after amputation of a nonregenerative limb. Nevertheless, nonregenerative epidermal tissue can reexpress fgf-8 under the influence of regenerative mesenchyme, as was demonstrated by experiments using a recombinant limb composed of regenerative limb mesenchyme and nonregenerative limb epidermis. Taken together, our data demonstrate that the regenerative capacity depends on mesenchymal tissue and suggest that fgf-10 is likely to be involved in this capacity. (C) 2000 Academic Press.
Bibliographical noteFunding Information:
We thank Drs. Shin Tochinai and Nobutaka Koibuchi at Hokkaido University (Japan) for the gift of Xenopus borealis and for the technical advice on limb bud transplantation. This work was supported by JSPS Research Fellowships for Young Scientists to H.Y., S.Y-T., T.E., and K.T. and by research grants from the Ministry of Education, Science, and Culture of Japan.
ASJC Scopus subject areas
- Molecular Biology
- Developmental Biology
- Cell Biology