Alignment defect of reaggregating cells in cultures of developing brains of reeler mutant mice

[摘要] Themechanismofcellalignmentandorientationindevelopingmousecerebralisocortexandcerebellarcortexwasanalyzedinreaggregatingcellculturesfromnormalandreelermutantmice.Isocorticalcellsdissociatedfromnormalfetusesat17.5to18.5daysofgestationreaggregatedoveraperiodofseveraldaysinvitroandformedaradiallysymmetricalpatterninwhichtheyoungneuronsreformedacorticalplateboundedexternallybyamolecularlayerandinternallybyacell-poornervefiberzone.Cellsfromreelerlittermatesformedsimilarsphericalaggregatesataboutthesamerate,buttheinnermostzonewasnotrecognizedandcellswithinthecorticalplateappearedrandomlyoriented.Cellsfromyoungeroroldermicedidnotalignintoacorticalpattern,andnodifferencesbetweennormalandreelerspecimenswerediscerned.Likewisecerebellarcellsdissociatedfromnormalmiceataround4daysafterbirthreaggregatedtoformabroadhomogeneousinternalzoneofsmallcellssegregatedfromalimitednumberoflarge,pale-stainingneurons;comparablecellsfromreelermice3–4daysoldfailedtoattainanypatternofhistologicalorganization.Itisshownthattheabilitytoaggregateisaseparateprocessfromthatofhistogeneticself-organizationofcellswithinanaggregate,andthatthelatterprocessisaffectedbyaspecificgeneticmutationknowntoaltercorticalorganization.Thesimilarityofpatternsofcellalignmentintheaggregatestothoseinvivoprobablyindicatesthatcellsintheaggregatesreproducetheinvivohistogeneticprocesses.Theresultsarguethatspecificcellalignmentinvivoisnotdependentonapreexistingtissuematrixoronthepatternedsequentialentryofcellsintothedevelopingcorticalplate.Adistinctionismadebetweenprimarymigrationandfinalcellalignment.Thereelergeneticlocusappearstoactdirectlyoncorticalcells,ratherthanatadistance,andprobablyaffectsamajorityofthecellsratherthanonlytheonesinitiallyreachingthecorticalplate.Thepossiblegeneticallydictatedpropertiesofcellswhichcouldaccountforthespecificalignmentinaggregatesarediscussed.

[学科分类] 生物科学（综合）