The IGF Pathway Regulates Head Formation by Inhibiting Wnt Signaling in Xenopus

摘要

Theinsulin-likegrowthfactors(IGFs)arewellknownmitogens,botheminvivo/emandeminvitro/em,whilefunctionsincellulardifferentiationhavealsobeenindicated.Here,wedemonstrateanewrolefortheIGFpathwayinregulatingheadformationinemXenopus/emembryos.BothIGF-1andIGF-2,alongwiththeirreceptorIGF-1R,areexpressedearlyduringembryogenesis,andtheIGF-1Rispresentparticularlyinanterioranddorsalstructures.OverexpressionofIGF-1leadstoanteriorexpansionofheadneuraltissueaswellasformationofectopiceyesandcementgland,whileIGF-1receptordepletionusingantisensemorpholinooligonucleotidesdrasticallyreducesheadstructures.Furthermore,wedemonstratethatIGFsignalingexertsthiseffectbyantagonizingtheactivityoftheWntsignaltransductionpathwayintheearlyembryo,atthelevelofβ-catenin.Thus,theIGFpathwayisrequiredforheadformationduringembryogenesis./p/div