THE SECRETED PRODUCT OF XENOPUS GENE LUNATIC FRINGE, A VERTEBRATE SIGNALING MOLECULE

Signaling molecules are essential for vertebrate embryonic development . Here, two Xenopus homologs of the Drosophila gene fringe, lunatic Fr inge (IFng) and radical Fringe (rFng), were identified and the protein product of IFng further characterized. The messenger RNA of IFng is s upplied as a maternal message, Its product is a precursor protein cons isting of pre-, pro-, and mature regions. The mature lunatic Fringe pr otein is secreted extracellularly, and it induced mesodermal tissue fo rmation in animal cap assays. These results indicate that secreted lun atic Fringe can induce mesoderm and reveal that the Fringe proteins ar e a family of vertebrate signaling molecules.