Pagliaccio, a member of the Eph family of receptor tyrosine kinase genes, has localized expression in a subset of neural crest and neural tissues in Xenopus laevis embryos.

Cranial neural crest cells arise from neural folds in the embryonic head and differentiate to produce most of the cartilages and bones of the skull and the somatosensory ganglia of several cranial nerves, among other tissues. Since the molecular basis of the determination of these cells is poorly understood, we have begun a search for molecules involved in signal transduction in cranial neural crest. From a Xenopus laevis cranial neural crest cDNA bank, we have cloned a cDNA encoding a putative receptor tyrosine kinase, which we call Pagliaccio (Pag). Pag RNA is present transiently in visceral arch 3, probably representing neural crest cells in this tissue. Pag is also expressed in the forebrain, rhombomeres r3 and r5 of the hindbrain and in the pronephros. Based on this localized expression, we propose that Pag may play a role in the differentiation of cranial neural crest and other tissues.