cis-Regulatory sequences driving the expression of the Hbox12 homeobox-containing gene in the presumptive aboral ectoderm territory of the Paracentrotus lividus sea urchin embryo

摘要

Embryonicdevelopmentiscoordinatedbynetworksofevolutionaryconservedregulatorygenesencodingtranscriptionfactorsandcomponentsofcellsignallingpathways.Intheseaurchinembryo,anumberofgenesencodingtranscriptionfactorsdisplayterritorialrestrictedexpression.Amongthese,thezygoticemHbox12/emhomeoboxgeneistransientlytranscribedinalimitednumberofcellsoftheanimal-lateralhalfoftheearlyemParacentrotuslividus/emembryo,whosedescendantswillconstitutepartoftheectodermterritory.ToobtaininsightsontheregulationofemHbox12/emexpression,wehaveexploredtheemcis/em-regulatoryapparatusofthegene.Inthispaper,weshowthattheintergenicregionofthetandememHbox12/emrepeatsdrivesGFPexpressioninthepresumptiveaboralectodermandthata234nbsp;bpfragment,definedaboralectoderm(AE)module,accountsfortherestrictedexpressionoftheemtransgene/em.Withinthismodule,aconsensussequenceforaSoxfactorandthebindingoftheOtxactivatorarebothrequiredforcorrectemHbox12/emgeneexpression.Spatialrestrictiontotheaboralectodermisachievedbyacombinationofdifferentrepressivesequenceelements.Negativesequenceelementsnecessaryforrepressionintheendomesodermmapwithinthemostupstream60nbsp;bpregionandnearbytheSoxbindingsite.Strikingly,aMyb-emlike/emconsensusisnecessaryforrepressionintheoralectoderm,whiledown-regulationatthegastrulastagedependsonaemGA/em-richregion.TheseresultssuggestaroleforemHbox12/eminaboralectodermspecificationandrepresentourfirstattemptintheidentificationofthegeneregulatorycircuitsinvolvedinthisprocess./p/div