Description:
NFkBResponsiveLuciferaseReporterMCF-7StableCellLineisderivedfromhumanbreastcancer,andstablyexpressfireflyluciferasereportergeneunderthecontroloftheNFkB responseelement. Thiscelllineisanidealcellularmodelformonitoringtheactivation ofNFkBReceptorSignalingPathwaytriggeredbystimulitreatment,enforcedgeneexpressionandgeneknockdown.Principle:
NFkBplaysanimportantroleincontrollingmanyBIOLOGicalprocessesincludingimmuneandinflammatoryresponses,developmentalprocesses,cellulargrowth,andapoptosis.Inresponsetothevariousstimuli,suchasstress,cytokines,freerADIcals,ultravioletirradiation,andbacterialorviralantigens,NFkBisactivatedandtranslocatesfromcytoplasmtonucleus,whereNFkBbindstoitsresponseelementonthepromoterregionandregulatesawidespectrumofgeneexpression.DysfunctionofNFkBactivityisassociatedwithcancer,inflammatoryandautoimmunedisease,andviralinfection.MonitoringtheNFkBactivityisessentialtounveilthemechanismofthesediseasesandconductdrugdiscovery.
SignosishasestablishedaNFkBluciferasereporterstablecelllinethathasbeenstablytransfectedwithpTA-NFkB-luciferasereportervectorandcanbeusedforstudyingNFkBsignalingpathwaysactivatedbydifferentcytokines,suchasTNFαandmanyotherstimuli,enforcedgeneexpressionandgeneknockdown.ThecelllinewasestablishedbytransfectionusingapTA-NFkB-luciferasereportervector,whichcontains4repeatsofNFkBbindingsites,aminimalpromoterupstreamofthefireflyluciferasecodingregion,alongwithhygromycinexpressionvectorfollowedbyhygromycinselection.ThehygromycinresistantclonesweresubsequentlyscreenedforTNFa-inducedluciferaseactivity.
PrinciplebehindTFluciferasereporter. TFluciferasereporterstablecelllineutilizesartificialpromoterconstructstodriveluciferaseexpression. Thepromoterregioncanconsistsofmultiplerepeatsofacis-elementTFbindingsite,aDNAfragmentfromthepromoterregionofaknownTFdownstreamgene,oraDNAfragmentcontainingputative/knownTFbindingsites. ThereareseveralwaysthataTFcanbeactivated,suchasthroughextracellularstimuliorthroughintracellularsignalingpathways. Onceactivated,theTFtranslocatestothenucleusandofteninteractswithrelevantco-factorstodrivegeneexpression. Onceluciferaseisexpressed,itcangeneratelightinanenzymaticassayandtheamountoflightmeasuredispositivelycorrelatedwiththelevelofTFactivation. |
Data:
AnalysisofSL-0013NFκBreporteractivityinresponsetoTNFαtreatment. TheMCF-7cellswereseededona96-wellplateforovernightincompletegrowthmedia. Thecellsthenweretreatedwithorwithout20ng/mlTNFαingrowthmediawith0.1%FBSfor16hours. MCF-7-NFkBLuciferaseReporterCellLineexhibitsTNFα-dependentincreaseinluciferaseactivitywhencomparedtountreatedcells.
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2.将构建完成的载体与慢病毒包装质粒混合,共转染靶细胞
3.收集病毒液
4.用病毒液感染靶细胞
5.用载体上带的抗生素进行筛选,如果没有,可以用无限稀释法
6.获得稳转株
一种是脂质体转染后,单克隆筛选稳定细胞株.另外一种是应用逆转录病毒,慢病毒转染,筛选稳定细胞株.
脂质体转染：在转染24小时后,消化细胞并计数.将细胞种到96孔板,保证每个孔2-3个细胞,这样才能得到单克隆.待细胞贴壁后,加入抗生素筛选.筛选时间和浓度视细胞而定.一般G418一个星期作用,嘌呤霉素2-3天.
脂质体法筛单克隆时间较长,且效率低,大概只有1%.
病毒转染：先要用包装细胞,一般为293细胞,包装出病毒,再用病毒转染目的细胞.包装病毒视不同类型的病毒而定,一般要3-5天的时间.包装好的病毒要测滴度,根据滴度决定转染目的细胞的病毒量.转染目的细胞1-2天后加抗生素筛选得到稳定细胞株.
病毒转染得到稳定细胞株的效率高,只是步骤繁琐.
至于到底好不好转就跟你的细胞有关了，和细胞是否是稳转株关系不大。
对于瞬时转染的检测：如果有报告基因，就通过报告基因的表达看转染成功与否；没有报告基因的话，就在24～96h内收获细胞通过RT-PCR和WB来鉴定。
推荐了解“主细胞库”“工作细胞库”这两个名词。
由于质粒的不兼容性,拥有同种复制子的质粒不能在同一细胞内稳定共存,经过几代的复制,会质粒丢失,所以并不是任何两个或两个以上质粒都可以在同一细胞内稳定存在,但是可以同时进入.
稳定转染的细胞株，就是转染后质粒可以稳定整合到基因组上不会因细胞分裂而丢失。区别于质粒瞬时转染不能长时间保留质粒在细胞里。
