Green fluorescent protein used to assess cranial neural crest derivatives in the frog, Xenopus laevis

We used RNA encoding green fluorescent protein (GFP) to study the migration and larval derivatives of cranial neural crest cells in the metamorphosing frog, Xenopus laevis. GFP provides an intrinsic cell-lineage marker that is retained after cell division. Moreover, because GFP label introduced at the one-cell stage continues to be expressed well after hatching, it offers a reliable and effective method for assessing the embryonic derivation of many larval, and possibly even adult, tissues in amphibians as well as other vertebrates. Basic patterns of cranial neural crest migration and derivation in X. laevis defined using GFP (including contributions to many larval cranial cartilages) arc similar to those documented in previous studies that used conventional vital stains, lineage markers, and ablation techniques. However, preliminary results also suggest the neural crest derivation of additional components of the larval anuran head, e.g., cranial bone, whose embryonic origins have proven much more difficult to resolve with other methods.