Alterations in the cell cycle of Drosophila imaginal disc cells precede metamorphosis
[摘要] FlowcytometricanalysesofimaginaldiscandbrainnucleiofDrosophilamelanogasterhavebeenmadethroughoutthethirdlarvalinstar.Inwing,haltere,andlegdiscstheproportionofcellsintheG2Mphaseofthecellcycle(tetraploidcells)increaseswithlarvalage.Incontrast,intheeyediscandinbraintheproportionoftetraploidcells,alreadylowattheoutsetoftheinstar,declinesfurther.MeasurementofgrowthratesfordiscandbraintissueduringthesamedevelopmentalperiodwascarriedoutbythecellcountingprocedureofMartin(1982).Ourresultsareconsistentwiththeconclusionthatimaginaldiscsgrowexponentiallywithanapparentdoublingtimeof5–10hrfromtheresumptionofcelldivision(inthefirstorsecondlarvalinstar)untilabout95hr,whentheapparentdoublingtimeincreases.Cellnumbersincreaseuntilatleast5hrafterformationofwhiteprepupae(122hr),butduringthepreceding10hrtherateofincreaseislow.Thus,forwingandlegdiscs,butnotfortheeyediscandbrain,thedeclininggrowthrateisassociatedwithanincreaseintheproportionsoftetraploidcells.Inconjunctionwithcellcountsandflowcytometry,fluorometricdeterminationofdiscDNAcontentat112hrindicatedthatthediploidDNAcontentofimaginaldiscnucleiis0.45pg.
[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] [时效性]
