CLONING AND INTERSPECIES COMPARISONS OF 3 NEWT (NOTOPHTHALMUS-VIRIDESCENS) FIBROBLAST GROWTH-FACTOR RECEPTOR SEQUENCES

We report the nucleotide sequences of two fibroblast growth factor rec eptor (FGFR) cDNAs, FGFR1 and FGFR3, from the newt species Notophthalm us viridescens. These two cDNA sequences and a previously published ne wt FGFR cDNA, FGFR2, were used to derive the amino acid sequences whic h were then compared with their homologues from other species. This co mparison shows that the intracellular tyrosine kinase domain is highly conserved across the species examined with the second half of the dom ain slightly more conserved than the first half. The 3' portion of the carboxyl terminal tail is not very highly conserved. The comparison o f the extracellular portion of FGFR2 shows a high degree of conservati on among the Ig-like domains and a low degree of conservation in the r egion that links the third Ig-like domain with the transmembrane domai n.