Distinct patterns of endosulfatase gene expression during Xenopus laevis limb development and regeneration

The heparan sulfate 6-O-endosulfatases sulf1 and sulf2 regulate multiple cellular processes and organ development. Sulfs modulate a range of heparan-sulfatedependent extracellular pathways, including the fibroblast growth factor, bone morphogenetic protein, and wingless/wnt signaling pathways. Known patterns of sulf transcript expression together with functional experiments have implicated the sulfs in chondrogenesis and muscle regeneration in mammals. Here, we describe the expression patterns of Xenopus laevis sulf1 and sulf2 in developing forelimbs and hindlimbs and demonstrate novel expression of the sulf transcripts in the regenerating hindlimbs, with prominent sulf2 expression in the proliferating blastema and transient expression of sulf1 in the redeveloping apical epidermal ridge. These findings further suggest involvement of the sulfs in successful limb regeneration in amphibians.