BACKGROUND:Studieshavesuggestedthatfibronectinleucine-richtransmembraneprotein3(FLRT3)isrelatedtoinjuryandregenerationofthenervoussystem.However,theexpressionandbiologicalcharacteristicsoftheseproteinsremainpoorlyunderstood.OBJECTIVE:ToobtainFLRT3C-terminalgenefragments,toeffectivelyexpressandpurifythetargetproteins.DESIGN,TIMEANDSETTING:AnobservationalstudyofcellularandmolecularbiologywasperformedatthelaboratoryofHistologyandEmbryologyinXiangyaSchoolofMedicine,CentralSouthUniversitybetweenOctober2007andJune2008.MATERIALS:ThreeSpragueDawleyadultratswereusedtoextracttotalRNAfromratbrains.ThepGEX4T3andEscherichiacoli(E.coli)JM109werepurchasedfromPromega.E.coliBL21wasprovidedbyNovagen.METHODS:FLRT3proteincodingC-terminalDNAfragments,atalengthof786bp,wereamplifiedusingRT-PCRtechniquefromrattotalRNA.TheamplifiedproductswereclonedintotheexpressionvectorpGEX4T3.ArecombinantexpressionvectorwasthenconstructedandintroducedintoE.coliBL21.IsopropyI-D-thiogalactopyranosidewasappliedtoinduceexpressionofrecombinantGSTfusionproteins,followedbyisolation,purification,andrenaturationofinclusionbodiesthatcomprisedrecombinantproteins.Finally,thepurifiedrecombinantproteinwasobtained.MAINOUTCOMEMEASURES:DeterminationofFLRT3C-terminalDNAsequence;expressionoftargetproteinswasassayedbySDS-PAGEelectrophoresis;purifiedrecombinantproteinwasidentifiedwithWesternblotmethods.RESULTS:FLRT3proteincodingC-terminalDNAfragments,atalengthof786bp,weresuccessfullyharvestedthroughRT-PCRamplification,andwerethenclonesintotheprokaryoticexpressionvectorpGEX4T3.Theresultsofthesequencewereconsistentwiththeknowngenesequence.SDS-PAGEanalysisdemonstratedthattherewasaspecificproteinbandintherecombinantGSTfusionproteinsatarelativemolecularmassof56,600.Therecombinantproteinwasobservedintheinclusionbody,andh
