Molecular cloning of the cDNA coding for Xenopus laevis prion protein

Isolation and characterization of the cDNA coding for the 216-residue Xenopus laevis prion protein is reported. Existence of this protein in amphibians was suggested by an EST fragment (accession number BG813008), while a conclusive demonstration is presented here. This protein exhibits a higher identity level to avian and turtle prion (more than 44%) than to mammalian prion (about 28%). Although most of the structural motifs common to known prion proteins are conserved in X. laevis. the lack of repeats represents a substantial difference. Other features worth noting are the presence of not perfectly conserved hydrophobic stretch, which is considered the prion signature, as well as the complete absence of histidine residues. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.