Rates of protein synthesis in explanted embryonic chick lens epithelia: Differential stimulation of δ-crystallin synthesis

[摘要] Cellsinthecentralregionof6-day-oldembryonicchicklensepitheliadisplaymorphologicalandbiochemicalchanges,whenculturedinmediumsupplementedwithfetalcalfserum,comparabletothoseoflensfibercellsdifferentiatinginvivo.Inthepresentstudytheratesofsynthesisoftotalproteinandofδ-crystallinwerequantitatedduringthefirstdayofculturebymeasuring(1)3H-valineincorporationintobulkproteinsandintoδ-crystallin(isolatedbyquantitativeimmunoprecipitation),(2)thespecificradioactivityofpicomolaramountsofintracellularvaline(determinedbyanalysisofthe14C-dansyl-derivativeof3H-valine),(3)theamountofproteindegradationoccurringduringthelabelingperiod(estimatedby“pulse-chase”experimentswithcycloheximide),and(4)thenumberofcellsintheexplants(countedfollowingdispersalwithtrypsin-EDTA).Theresultsshowedthattotalproteinsynthesisincreased1.7-foldpercellduringthefirst24hrsinvitro.Incontrast,δ-crystallinsynthesisincreased2.8-foldpercellduringthistime.Theseexperimentsestablishthatδ-crystallinsynthesisisdifferentiallystimulatedinepitheliaculturedinserum-supplementedmedium,andprovidethebasisforquantitativeanalysisofthemechanismcontrollingdifferentialproteinsynthesisduringlensfiberdifferentiationinvitro.

[学科分类] 生物科学（综合）