Temperature sensitivity of muscle and neuron differentiation in embryonic cell cultures from the Drosophila mutant, shibirets1☆

[摘要] Thesex-linkedtemperature-sensitivemutation,shibirets1,whichcauses,attherestrictivetemperature,adultparalysisandpleiotropicmorphologicaldefectsinembryonic,larval,andpupaldevelopment,hasbeenshowntoexhibittemperature-sensitiveinhibitionofdifferentiationinembryonicculturesinvitro.Whenshicultureswereincubatedat30°Cfor24hr,bothmuscleandneurondifferentiationwereinhibitedmorethan90%comparedtocontrolshiculturesincubatedat20°C.Heatshiftexperimentsshowedthatthetemperature-sensitiveperiodsforneuronandmuscledifferentiationoccurredat11to18and14to16hr,respectively,wherezerotimewastheinitiationofgastrulationindonorembryos.Shortheatpulses(4and8hr)whichextendedintothetemperature-sensitiveperiodresultedinmoderateinhibitionofdifferentiation;greaterinhibitionoccurredasthedurationofthepulsesincreased.Incontrast,heatingwild-typeOregon-Rculturesat30°Cfor24hrdidnotinhibitmusclecelldifferentiationandinhibitedneurondifferentiationrelativelylittle.Thetemperature-sensitiveperiodinshibireformuscledifferentiationoccurredwellaftermyoblastdivision,duringtheperiodofmyocyteelongation,aggregation,andfusion,whereasthatforneurondifferentiationtookplaceduringaperiodofenzymesynthesis(acetylcholinesteraseandcholineacetyltransferase)andaxonelongation.Thus,theshitemperature-sensitivegeneproductaffectsatleasttwodifferentcelltypes,invitro,atdifferenttimesduringdifferentiation.

[学科分类] 生物科学（综合）