简介:研究在BEP2D细胞中,作为Smads蛋白家族的抑制分子,Smad7对胞外信号调节的蛋白激酶(ERK1/2或p44/42)磷酸化水平的调控。将Smad7真核表达载体或人工合成的Smad7-siRNA转染BEP2D细胞,TGF—β刺激,通过Western印迹检测Smad7对p44/42蛋白磷酸化的影响。结果在永生化BEP2D细胞中,TGF-β1刺激后5min开始,可以检测到磷酸化的p44/42;到60min达到高峰,之后逐渐降低。细胞转染Smad7,TGF-β作用60rain后,p44/42磷酸化水平明显增高;而转染Smad7-SiRNA,TGF-β作用60min后,p44/42磷酸化水平显著降低。p44/42蛋白水平基本上不受TGF—β1刺激及Smad7表达水平的影响。以上结果说明,在BEP2D细胞中,Smad7可参与TGF—β对ERK/MAPK通路的活化作用。
简介:TRAF2isacriticaladaptormoleculeforTNFreceptorsininflammatoryandimmunesignaling.Uponreceptorengagement,TRAF2isrecruitedtoCD40andtranslocatestolipidraftsinaRINGfinger-dependentprocess,whichenablestheactivationofdownstreamkinases.TRAF1candisplaceTRAF2andCD40fromraftfractions,anditpromotestheabilityofTRAF2tosustainsignalactivation.ReplacementoftheRINGfingerofTRAF2witharaft-targetingsignalrestoresJNKactivationandassociationwiththecytoskeletalproteinFilamin,butnotNF-KBactivation.TRAF1-/-dendriticcellsshowattenuatedresponses
简介:根据Genbank中大肠杆菌嘌呤核苷磷酸化酶(PNP)基因的核苷酸序列,设计并合成了一对引物,以大肠杆菌基因组DNA为模板,进行PCR扩增,并将扩增产物定向连接到克隆、测序及真核表达载体PCDNA3中,进行酶切鉴定、测序及序列分析。结果表明PCR扩增出741bp大小的片段,通过酶切和序列分析证明含完整的PNP基因序列且基因插入方向正确,此序列与文献报道的PNP基因的同源性为99.7%。说明克隆的PNP基因与文献报道的基本一致,pcDNA3-PNP的构建成功为今后用其进行基因转染来研究PNP/Mep-dR自杀基因系统在肿瘤基因治疗中的应用打下了基础。
简介:<正>Usingsubtractioncloning,weidentifiedthehumanN-MycDownstream-RegulatedGene-2(hNDRG2),locatedat14q11.2,asacandidatetumorsuppressorgene.Semi-quantitativeRT-PCRshowedthattheexpressionofhNDRG2in15of27(56%)humanGBMtissuesandall6humanglioblastomacelllineswassignificantlylowerthanthatinthenormalbrain.TheexpressionofhNDRG2alsowasevaluatedin60lung-carcinomapatients.17of26casesofsquamouscarcinomaand4of11casesofsmallcelllungcancerdisplayed
简介:GelatinaseA(MMP-2)isconsideredtoplayacriticalroleincellmigrationandinvasion.Theproteinaseiscercetedfromthecellasaninactivezymogen.InvivoitispostulatedthatactivationofprogelationaseA(proMMP-2)takesplaceonthecellsurfacemediatedbymembrane-typematrixmetalloproteinases(MT-MMPs).RecentstudieshavedemonstratedthatproMMP-2isrecruitedtothecellsurfacebyinteractingwithtissueinhibitorofmetalloproteinases-2(TIMP-2)boundtoMT1-MMPbyformingaternarycomplex.FreeMT1-MMPcloselylocatedtotheternarycomplexthenactivatesproMMP-2onthecellsurface.MT1-MMPisfoundinculturedinvasivecancercellsattheinvadopodia.TheMT-MMP/TIMP-2/MMP-2systemthusprovideslocalizedexpressionofproteolysisoftheextracellularmatrixrequiredforcellmigration.
简介:ErbB2,amemberofthereceptortyrosinekinasefamily,isfrequentlyover-expressedinbreastcancer.ProteolysisoftheextracellulardomainofErbB2resultsinconstitutiveactivationofErbB2kinase.RecentstudyreportedthatErbB2isfoundinthenucleus.Here,weshowedthatErbB2isimportedintothenucleusthroughanuclearlocalizationsignal(NLS)-mediatedmechanism.TheNLSsequenceKRRQQKIRKYTMRR(aa655-668)containsthreeclustersofbasicaminoacidsanditissufficienttotargetGFPintothenucleus.However,mutationinanybasicaminoacidclusterofthisNLSsequencesignificantlyaffectsitsnuclearlocalization.Furthermore,itwasfoundthatthisNLSisessentialforthenuclearlocalizationofErbB2sincetheintracellulardomainofErb2lackingNLScompletelyabrogatesitsnucleartranslocation.Takentogether,ourstudyidentifiedanovelnuclearlocalizationsignalandrevealsanovelmechanismunderlyingErbB2nucleartraffickingandlocalization.
简介:One-cellmouseembryosfromKMstrainandB6C3F1strainwereculturedinM16medium,inwhich2-cellblockgenerallyoccurs.EmbryosofKMstrainexhibited2-cellblock,whereasB6C3F1embryos,whichareregardedasanonblockingstrain,proceededtothe4-cellstageinourculturecondition.Itisoftenassumedthattheblockofearlydevelopmentisduetothefailureofzygoticgeneactivation(ZGA)inculturedembryos.Inthisstudyweexaminedproteinsynthesispatternsbytwo-dimensionalgelelectrophoresisof[35S]methionineradiolabeled2-cellembryos.Embryosfromtheblockingstrainandthenonblockingstrainwerecomparedintheirdevelopmentbothinvitroandinvivo.ThedetectionofTRCexpression,amarkerofZGA,at42hposthCGinKMembryosdevelopedinvitrosuggestedthatZGAwasalsoinitiatedeveninthe2-cellarrestedembryos.Nevertheless,asignificantdelayofZGAwasobservedinKMstrainascomparedwithnormallydevelopedB6C3F1embryos.AttheverybeginningofmajorZGAasearlyas36hposthCG,TRChasalreadybeenexpressedinB6C3F1embryosdevelopedinvitroandKMembryosdevelopedinvivo.Butfor2-cellblockedKMembryos,TRCwasstillnotdetectableevenat38hposthCG.Theseevidencessuggestthat2-cell-blockedembryosdoinitiateZGA,andthat2-cellblockphenomenonisduenottothedisabilityininitiatingZGA,buttoadelayofZGA.
简介:Humantumornecrosisfactorα(hTNFα),apleiotropiccytokinewithactivitiesrangingfromhostdefensemechanismsininfectionandinjurytoseveretoxicityinsepticshockorotherrelateddiseases,isapromisingtargetfordrugscreening.UsingtheSELEX(systematicevolutionofligandsbyexponentialenrichment)process,weisolatedoligonucleotideligands(aptamers)withhighaffinitiesforhTNFα.Aptamerswereselectedfromastartingpoolof40randomizedsequencescomposedofabout1015RNAmolecules.RepresentativeaptamersweretruncatedtotheminimallengthwithhighaffinityforhTNFαandwerefurthermodifiedbyreplacementof2'-OHwith2'-Fand2'-NH2atallribopurinepositions.ThesemodifiedRNAaptamerswereresistanttonuclease.ThespecificityoftheseaptamersforhTNFαwasconfirmed,andtheiractivitytoinhibitthecytotoxicityofhTNFαonmouseL929cellswasdetermined.Resultsdemonstratedthatfour2'-NH2-modifiedaptamersboundtohTNFαwithhighaffinityandblockedthebindingofhTNFαtoitsreceptor,thusprotectingtheL929cellsfromthecytotoxicityofhTNFα.OligonucleotideaptamersdescribedherearepotentialtherapeuticsanddiagnosticsforhTNFc-relateddiseases.
简介:Domaindatabaseisessentialfordomainpropertyresearch.Eliminatingredundantinformationindatabasequeryisveryimportantfordatabasequality.Herewereportthemanualconstructionofanon-redundanthumanSH2domaindatabase.Thereare119humanSH2domainsin110SH2-containingproteins.HumanSH2swerealignedwithClustalX,andahomologoustreewasgenerated.Inthistree,proteinswithsimilarknownfunctionwereclassifiedintothesamegroup.Someproteinsinthesamegrouphavebeenreportedtohavesimilarbindingmotifsexperimentally.Thetreemightprovidecluesaboutpossiblefunctionsofhypotheticalproteinsforfurtherexperimentalverification.
简介:Inordertostudythemechanismoftheeffectofheparinonapoptosisincarcinomacells,thenasopharyngealcarcinomacelllineCNE2wasusedtoidentifytheeffectofheparinonapoptosisassociatedwiththeexpressionofc-myc,bax,bcl-2proteinsbyuseofHoechst33258staining,terminaldeoxynucleotidyltransferase-mediateddUTPnick-endlabeling(TUNEL),agarosegelelectrophoresis,andflowcytometry,aswellasWesternblotanalysis.TheresultsshowedthatheparininducedapoptosisofCNE2cellsincludingthemorphologicchangessuchasreductioninthevolume,andthenuclearchromatincondensation,aswellasthe“ladderpattern”revealedbyagarosegelelectrophoresisofDNAinaconcentration-dependentmanner.ThenumberofTUNEL-positivecellswasdramaticallyincreasedto33.6±1.2%from2.8±0.3%bytreatmentwithheparinindifferentconcentrations(10~40kU/L).Theapoptoticindexwasincreasedto32.5%from3.5%bydetectingSubG1peaksonflowcytometry.Westernblotanalysisshowedthatlevelsofbcl-2,baxandc-mycweresignificantlyoverexpressedbytreatmentwiththeincreaseofheparinconcentrations.TheseresultssuggestthatheparininducesapoptosisofCNE2cells,whichmayberegulatedbydifferentialexpressionofapoptosis-relatedgenes.
简介:Apoptosismanifestsintwomajorexecutionprogramsdownstreamofthedeathsignal:thecaspasepathwayandorganelledysfunction.Animportantantiapoptosisfactor,Bcl-2protein,contributesincaspasepathwayofapoptosis.Calcium,animportantintracellularsignalelementincells,isalsoobservedtohavechangesduringapoptosis,whichmaybeaffectedbyBcl-2protein.WehavepreviouslyreportedthatinHarringtonine(HT)inducedapoptosisofHL-60cells,there'schangeofintracellularcalciumdistribution,ovingfromcytoplastespeciallyGolgi'sapparatustonucleusandaccumulatingtherewiththehighestconcentration.Wereportherethatcaspase-3becomesactivatedinHT-inducedapoptosisofHL-60cells,whichcanbeinhibitedbyoverexpressionofBcl-2protein.NosignofapoptosisorintracellularcalciummovementfromGolgi'sapparatustonucleusinHL-60cellsoverexpressingBcl-2ortreatedwithAc-DEVD-CHO,aspecificinhibitorofcaspase-3.Theresultsindicatethatactivatedcaspase-2canpromotethemovementofintracellularcalciumfromGolgi'sapparatustonucleus,andtheprocessisinhibitedbyAc-DEVD-CHO(inhibitorofcaspase-3),andthatBcl-2caninhibitthemovementandaccumulationofintracellularcalciuminnucleusthroughitsinhibitiononcaspase-3.Calciumrelocalizationinapoptosisseemstobeirreversible,whichisdifferentfromtheintracellularcalciumchangescausedbygrowthfactor.
简介:Threetypesofroughsurfacewereprocessedbylaserirradiationonthe3Cr2W8Vmaterialhot-workdiesteelsurface.Thewearexperimentswithsmoothsurfaceandroughsurfacesampleswererepeatedonthepin-traywearmachine.Accordingtothewearresults,westudiedtheregularityofwearresistanceofdifferentroughsurfacesamples.Theresultsindicatedthatbionicroughsurfacecanimprovethewearresistanceofthematerialandthewearresistancecanbeincreased1-2times,comparedwiththesmoothsurface.Also,thewearresistanceoftheroughsurfacewasaffectedbylasercurrentanddurationofimpulse.Thebiggerthelasercurrentortheimpulseduration,thebetteristhewearresistance.Whenthedistancebetweenthesamekindofunitswhicharedistributedonthesurfacesischanged,thewearresistancechanges.Thewearresistanceofabionicroughsurfaceonwhichthegridunitsweredistributedatspacingof1mmwasthebest.Andwedesignedthewearmodels.