The Expression Pattern of the Chick Homeobox Gene gMHox Suggests a Role in Patterning of the Limbs and Face and in Compartmentalization of Somites

[摘要] MHoxisahomeodomainproteinthatbindsanessentialelementinthecoreofthemusclecreatinekinaseenhancer.Inthemouseembryo,MHoxexpressionisrestrictedtomesenchymalcells;inadultmicethegeneishighlyexpressedinskeletalandcardiacmuscle.TofurtherdefinethefunctionsofMHoxduringembryogenesis,wehavecloneditschickenhomolog,termedgMHox,andanalyzeditspropertiesanddetailedexpressionpatterns.OurstudiesshowthattheaminoacidsequenceandDNA-bindingpropertiesoftheavianandmurinegeneproductsareverysimilar.Furthermore,thesitesofexpressionarealikewithhighlevelsofexpressioninthesplanchnicmesoderm,inthesomaticmesoderm,inthelimbbudmesoderm,inthedermatomeandinthedermis,andintheectomesenchymeoftheface.gMHoxbecamedownregulatedaschondrogenesisproceeded,whereasitsexpressionwasmaintainedinperichondriumandundifferentiatedmesenchymalcellsbeneaththesurfaceectoderm.SuchapatternofexpressionsuggeststhatgMHoxmayparticipateinmaintenanceofmesenchymalcelllineagesderivedfrombothmesodermandtheneuralcrestandinpatterningofthelimbsandtheface.RemovalofthesurfaceectodermoverlyingthesomiteshasnovisibleeffectonthearchitectureofsomitesbutresultsinthefailureofgMHoxtobeexpressedintheunderlyingdermatome,suggestingthatregulationofgMHoxexpressioninthesecellsisdependentoncuesemanatingfromthesurfaceectoderm.

[学科分类] 生物科学（综合）