Developmental changes in messenger RNAs and protein synthesis in Dictyostelium discoideum☆
[摘要] ThepatternofproteinssynthesizedatdifferentstagesofdifferentiationoftheslimemoldDictyosteliumdiscoideumwasstudiedbytwo-dimensionalpolyacrylamidegelelectrophoresis.Oftheapproximately400proteinsdetectedduringgrowthand/ordevelopment,synthesisofmostcontinuedthroughoutdifferentiation.Approximately100proteinsshowchangesintheirrelativeratesofsynthesis.Duringthetransitionfromgrowthtointerphase,themajorchangeobservedisreductionintherelativerateofsynthesisofabout8proteins.Fewfurtherchangesarenoticeableuntilthestageoflatecellaggregation,whenproductionofabout40newproteinsbeginsandsynthesisofabout10isreducedconsiderably.Thereafter,therearefewchangesinthepatternofproteinsynthesis.Majorchangesintherelativeratesofsynthesisofanumberofproteinsarefoundduringculmination,butfewculmination-specificproteinsareobserved.Inanattempttounderstandthemolecularbasisforthesechanges,mRNAwasisolatedfromdifferentstagesofdifferentiationandtranslatedinanimprovedwheatgermcell-freesystem;theproductswereresolvedontwo-dimensionalgels.TheratiooftotaltranslatablemRNAtototalcellularRNAisconstantthroughoutgrowthanddifferentiation.MessengerRNAsformany,butnotall,developmentallyregulatedproteinscanbeidentifiedbytranslationincell-freesystems.Actinisthemajorproteinsynthesizedbyvegetativecellsandbyearlydifferentiatingcells.Thethreefoldincreaseintherelativerateofsynthesisofactinduringthefirst2hrofdifferentiationandthedecreasewhichoccursthereaftercanbeaccountedforbyparallelchangesintheamountoftranslatableactinmRNA.MostofthechangesinthepatternofproteinsynthesiswhichoccurduringthelateaggregationandculminationstagescanalsobeaccountedforbyparallelincreasesordecreasesintheamountsoftranslatablemRNAsencodingtheseproteins.ItisconcludedthatmRNAsdonotappearinatranslatableformbeforesynthesisofthehomologousproteinbegins,andthatregulationofproteinsynthesisduringdevelopmentisprimarilyatthelevelsofproductionordestructionofmRNA.
[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]
