The cDNA for a novel member of the FGFR family, named Ai FGFR, was isolated
from a Halocynthia roretzi cDNA library prepared at the mid-tailbud stage.
This cDNA was 3507b long, and the deduced amino acid sequence contained a
motif characteristic of the vertebrate FGFRs. The existence of a single cop
y of the FGFR homologue gene in H. roretzi was suggested by restriction sit
e analysis of multiple clones. HrFGFR mRNA was expressed strongly in the po
sterior region in the epidermis from the middle neurula stage. By contrast,
Xenopus FGFR homologues are expressed in the anterior region and are known
to induce anterior neural formation. A transition of the region expressing
FGFR might have induced the more complicated brain or head formation chara
cteristic of vertebrates. (C) 2000 Academic Press.