Pattern Formation in a Pentameral Animal: Induction of Early Adult Rudiment Development in Sea Urchins

Developmental Biology

Rudolf A. Raff¹  Sharon B. Minsuk¹ 

[1] Department of Biology and Indiana Molecular Biology Institute, Indiana University, Bloomington, Indiana, 47405

关键词: induction;    signaling;    mesoderm;    coelom;    hydrocoel;    vestibule;    rudiment;    modularity;    skeletal patterning;   

DOI  :  10.1006/dbio.2002.0704

学科分类：生物科学（综合）

来源: Academic Press

【 摘 要 】

Weinvestigatedadultrudimentinductioninthedirect-developingseaurchinHeliocidariserythrogrammamicrosurgically.Afterremovalofthearchenteron(whichincludespresumptivecoelomicmesodermaswellaspresumptiveendoderm)fromlategastrulae,larvalectodermdevelopsproperlybutobviousrudiments(tubefeet,nervoussystem,andadultskeleton)failtoform,indicatingthatcoelomicmesoderm,endoderm,orbotharerequiredforinductionofadultdevelopment.Recombinationofectodermandarchenteronrescuesdevelopment.Implantedendodermaloneorleftcoelomaloneeachregeneratethefullcomplementofarchenteronderivatives;thus,theyareuninformativeastotherelativeinductivepotentialofthetworegions.However,inisolatedectoderm,morelimitedregenerationgivesrisetolarvaecontainingnoarchenteronderivativesatall,endodermonly,orbothendodermandleftcoelom.Adultnervoussystembeginstodeveloponlyinthelatter,indicatingthatleftcoelomisrequiredfortheinductivesignal.Isolatedectodermdevelopsavestibule(theprecursorofadultectoderm)andcorrectlyregulatesvestibularexpressionoftheectodermalterritorymarkerHeET-1,indicatingthattheearlyphaseofvestibuledevelopmentoccursautonomously;onlylaterdevelopmentrequirestheinductivesignal.Anotherectodermalmarker,HeARS,isregulatedproperlyinthelarvalectodermregion,butnotinthevestibule.HeARSregulationthusrepresentsanearlyresponsetotheinducingsignal.WecompareHeARSexpressioninH.erythrogrammawiththatinindirectdevelopersanddiscussitsimplicationsformodularityintheevolutionofdevelopmentalmode.

【 授权许可】

Unknown