Induction of stalk cell differentiation by cyclic-AMP in a susceptible variant of Dictyostelium discoideum☆

[摘要] TheP-4variantofDictyosteliumdiscoideum(DdH)wasfoundtoproduceagreatexcessofstalkcellscomparedtothewildtypeDdH.IfthevegetativecellsofP-4wererepeatedlywashed,thevariantchangedbacktothewildtypephenotype,andifcyclic-AMPwasaddedtothewashedP-4cells,thevariantcharacterwasrestored.Furthermore,iftheconcentrationofaddedcyclic-AMPwasincreased,itwaspossibletoinduce100%stalkcellsinP-4.Phosphodiesterasewouldcausethevarianttochangetothewildtype,while5-AMPandcyclic-nucleotidesotherthancyclic-AMPhavenoeffectatall.Thereforeitwasconcludedthatcyclic-AMPplaysakeyroleinstalkcelldifferentiation.AcomparisonbetweenwildtypeDdHandthevariantP-4showedthatDdHistentimeslesssensitivetocyclic-AMPinduction.Theybothproducethesameamountofcyclic-AMPandextracellularphosphodiesterase,butthespecificactivityofP-4cell-boundphosphodiesteraseduringdevelopmentissignificantlylessthanthatintheDdH.OnehypothesisthataccountsfortheP-4-DdHdifferenceisthatbecauseofthelackofcell-boundphosphodiesterase,morecyclic-AMPentersthevariantcellsandhencemorestalkcelldifferentiation.

[学科分类] 生物科学（综合）