Cell-cell contact and cAMP regulate the expression of a UDP glucose pyrophosphorylase gene of Dictyostelium discoideum☆

摘要

UDPglucosepyrophosphorylase(UDPGP)(EC.2.7.7.9)isadevelopmentallyregulatedenzymeofDictyosteliumdiscoideum.TwopolypeptidesofUDPGParetranslatedfromDictyosteliummRNA.RecentlyweisolatedacDNAclonewhichencodesoneoftheUDPGPpolypeptides(B.R.Fishel,J.A.Ragheb,A.Rajkovic,B.Haribabu,C.W.Schweinfest,andR.P.Dottin(1985).Dev.Biol.110,369a€“381).ByhybridizationwiththecDNAandbyinvitrotranslationandimmunoprecipitation,weexaminedtheeffectofcell-cellcontactandcAMPontheregulationofUDPGPexpression.DisaggregationofslugsresultedinarapidlossofUDPGPmRNA.AdditionofcAMPtothesecellsresultedinincreasedlevelsofUDPGPmRNA,thoughnottothesameextentasseenduringnormaldevelopment.ThetwoUDPGPpolypeptidesobservedinvitroarecoordinatelyregulated.Unaggregatedcells,starvedandshakenrapidlyinsuspension,didnotshowUDPGPmRNAaccumulation.However,additionofcAMPtothesecellscausedUDPGPinduction,suggestingthattherequirementforcell-cellcontactcouldbebypassedinpartbycAMPaddition.