Notch signaling during larval and juvenile development in the polychaete annelid Capitella sp. I

摘要

Notchsignalingisinvolvedinalargerangeofdevelopmentalprocesses,andhasbeenfunctionallyimplicatedinbodyplansegmentationintwoofthethreediversesegmentedtaxa,thevertebratesandarthropods.HereweinvestigateexpressionofemNotch/em,emDelta/em,andemhes/emgenehomologuesduringlarvalandjuveniledevelopmentinthepolychaeteannelidemCapitella/emsp.I.,amemberofthethirdgroupofsegmentedanimals.Duringlarvalstages,emCapI-Notch/em,emCapI-Delta/em,emCapI-hes2/em,andemCapI-hes3/emtranscriptsareinitiallydetectedinbroadectodermaldomainsinfuturesegmentsaswellasinthebrainandforegut;later,emCapI-Notch/em,emCapI-Delta/em,andemCapI-hes2/emtranscriptsaredetectedinthepresumptivechaetalsacs.Incontrast,emCapI-hes1/emhasasegmentallyreiteratedpatterninarestrictedregionofthemesodermineachpresumptivesegment.emCapI-Notch/em,emCapI-Delta/em,emCapI-hes2/em,andemCapI-hes3/emandemCapI-hes1/emareallexpressedintheterminalgrowthzonethatgeneratespost-metamorphicsegments,however,emCapI-hes1/emhasanon-overlappingcomplementaryexpressionpatterntothatofemCapI-Notch/emandemCapI-Delta/em.emCapI-Delta/emandemCapI-Notch/emtranscriptsarelocalizedtoalreadyformedsegments,withposteriorboundariesthatcorrelatewiththeposteriorboundaryofthenascentsegment,whileemCapI-hes1/emliesposteriortoemCapI-Notch/emandemCapI-Delta/em.ThelocalizationofemCapI-Notch/em,emCapI-Delta/em,andemCapI-hes/emtranscriptscorrelatewithareasofrapidcellproliferationinemCapitella/em,whichincludethebrain,foregut,andterminalgrowthzone./p/div