The Outflow Tract of the Heart Is Recruited from a Novel Heart-Forming Field
[摘要] Asclassicallydescribed,theprecardiacmesodermofthepairedheart-formingfieldsmigrateandfuseanteriomediallyintheventralmidlinetoformthefirstsegmentofthestraighthearttube.Thissegmentultimatelyformstherighttrabeculatedventricle.Additionalsegmentsareaddedtothecaudalendofthefirstinasequentialfashionfromtheposteriolateralheart-formingfieldmesoderm.Inthisstudywereportthatthefinalmajorheartsegment,whichformsthecardiacoutflowtract,doesnotfollowthispatternofembryonicdevelopment.Thecardiacoutlet,consistingoftheconusandtruncus,doesnotderivefromthepairedheart-formingfields,butoriginatesseparatelyfromapreviouslyunrecognizedsourceofmesodermlocatedanteriortotheinitialprimitivehearttubesegment.Fate-mappingresultsshowthatcellslabeledinthemesodermsurroundingtheaorticsacandanteriortotheprimitiverightventricleareincorporatedintoboththeconusandthetruncus.Conversely,ifcellsarelabeledintheexistingrightventriclenoincorporationintothecardiacoutletisobserved.Tissueexplantsmicrodissectedfromthisanteriormesodermregionarecapableofformingbeatingcardiacmuscleinvitrowhencoculturedwithexplantsoftheprimitiverightventricle.Thesefindingsestablishthepresenceofanotherheart-formingfield.Thisanteriorheart-formingfield(AHF)consistsofmesodermsurroundingtheaorticsacimmediatelyanteriortotheexistinghearttube.Thisnewconceptoftheheartoutlet'sembryonicoriginprovidesanewbasisforexplainingavarietyofgene-expressionpatternsandcardiacdefectsdescribedinbothtransgenicanimalsandhumancongenitalheartdisease.
[发布日期] [发布机构]
[效力级别] [学科分类] 生物科学（综合）
[关键词] embryo;heart;heart defects;congenital;gene expression regulation;developmental;embryonic induction;mesoderm;cell differentiation;morphogenesis;microinjections;tissue culture [时效性]
