Identification and characterisation of the posteriorly-expressed Xenopus neurotrophin receptor homolog genes fullback and fullback-like.

We have identified fullback and fullback-like, two Xenopus laevis neurotrophin receptor homolog (NRH1) genes. The sequences of Fullback and Fullback-like are very similar to that of the neurotrophin receptor p75NTR, in both their extracellular and their intracellular domains. As their names imply, fullback and fullback-like are expressed in essentially identical patterns in the posterior of the embryo from the early gastrula stage onward. At tailbud and tadpole stages transcripts are also present in dorsal somites and the head, in addition to the growing tailbud. This expression pattern differs from that of p75NTR, suggesting that fullback and fullback-like have different functions from p75NTR during early development.