We cloned the chick homolog of Xenopus and mouse Frzb-1, a secreted Wnt ant
agonist and performed in situ hybridisations to determine the pattern of cF
rzb-1 expression in the developing chick embryo. At early stages, cFrzb-1 t
ranscripts are located exclusively in the ectodermal layer corresponding to
the neural plate. The labelling continues in the neural tube, but is alway
s excluded from the floor plate, cFrzb-1 mRNA is expressed by migrating cep
halic and truncal neural crest cells. Later, cFrzb-1 transcripts are found
in a subset of neural crest derivatives such as cephalic cartilage, nerves
and spinal ganglia. In addition to ectodermal derivatives, cFrzb-1 transcri
pts were also observed in mesodermal derivatives such as vertebral and limb
cartilage, the adrenal cortex, the gonads, and a subpopulation of blood ce
lls. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.