<i>Fgf10</i> mutant newts regenerate normal hindlimbs despite severe developmental defects.

Abstract

In amniote limbs, Fibroblast Growth Factor 10 (FGF10) is essential for limb development, but whether this function is broadly conserved in tetrapods and/or involved in adult limb regeneration remains unknown. To tackle this question, we established <i>Fgf10</i> mutant lines in the newt <i>Pleurodeles waltl</i> which has amazing regenerative ability. While <i>Fgf10</i> mutant forelimbs develop normally, the hindlimbs fail to develop and downregulate FGF target genes. Despite these developmental defects, <i>Fgf10</i> mutants were able to regenerate normal hindlimbs rather than recapitulating the embryonic phenotype. Together, our results demonstrate an important role for FGF10 in hindlimb formation, but little or no function in regeneration, suggesting that different mechanisms operate during limb regeneration versus development.