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：Theeventsofcelldeathandtheexpressionofnuclearmatrixprotein(NMP)havebeeninvestigatedinapromyelocyticleukemiccelllineHL-60inducedwithetoposide.BymeansofTUNELassay,thenucleidisplayedacharacteristicmorphologychange,andtheamountofapoptoticcellsincreasedearlyandreachedmaximunabout39%aftertreatmentwithetoposidefor2h.NucleosomalDNAfragmentationwasobservedaftertreatmentfor4h.ThemorphologicalchangeofHL-60cells,thus,occurredearlierthantheappearanceofDNAladder.Totalnuclearmatrixproteinswereanalyzedby2-dimensionalgelelectrophoresis.Differentialexpressionof59nuclearmatrixproteinswasfoundin4hetoposidetreatedcells.Westernblottingwasthenperformedonthreenuclearmatrixacssociatedproteins,PML,HSC70andNuMA.TheexpressionofthesuppressorPMLproteinandheatshockproteinHSC70weresignificantlyupregulatedafteretoposidetreatment,whileNuMA,anuclearmitoticapparatusprotein,wasdownregulated.Theseresultsdemonstratethatsignificantbiochemicalalterationsinnuclearmatrixproteinstakeplaceduringtheapoptoticprocess.

简介：ToexplorethemolecularmechanismofchromatinremodelinginvolvedintheregulationoftranscriptionalactivationofspecificgenesbyamyogenicregulatoryfactorMyogenin,weusedNIH3T3fibroblastswithastablyintegratedH1.1-GFPfusionproteintomonitorhistoneH1movementdirectlybyfluorescencerecov-eryafterphotobleaching(FRAP)inlivingcells.TheobservationfromFRAPexperimentswithmyogenintransfectedfibroblastsshowedthattheexchangerateofhistoneH1inchromatinwasobviouslyincreased,indicatingthatforcedexpressionofexogenousMyogenincaninducechromatinremodeling.Thehyper-acetylationofhistonesH3andH4frommyogenintransfectedfibroblastswasdetectedbytriton-acid-urea(TAU)/SDS(2-D)electrophoresisandWesternblotwithspecificantibodiesagainstacetylatedN-terminiofhistonesH3andH4.RT-PCRanalysisindicatedthatthenAChRa-subunitgenewasexpressedinthetrans-fectedfibroblasts.TheseresultssuggestthattheexpressionofexogenousMyogenincaninducechromatinremodelingandactivatethetranscriotionofMvogenin-targetedgeneinnon-musclecells.