Molecular cloning chapter 07.docx
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Molecularcloningchapter07
Chapter7Extraction,Purification,andAnalysisofmRNAfromEukaryoticCells
Protocol1:
PurificationofRNAfromCellsandTissuesbyAcidPhenol-GuanidiniumThiocyanate-ChloroformExtraction
Inthissingle-steptechnique,cellsarehomogenizedinguanidniumthiocyanateandtheRNAispurifiedfromthelysatebyextractionwithphenol:
chloroformatreducedpH.Manysamplescanbeprocessedsimultaneouslyandspeedily.TheyieldoftotalRNAdependsonthetissueorcellsourceandisgenerallyintherangeof4-7µg/mlstartingtissueor5-10µg/106cells.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol2:
ASingle-stepMethodfortheSimultaneousPreparationofDNA,RNA,andProteinfromCellsandTissues
Thisprotocol,avariationofthemethoddescribedinChapter7,Protocol1,involveslysisofcellsinamonophasicsolutionofguanidineisothiocyanateandphenol.Additionofchloroformgeneratesasecond(organic)phaseintowhichDNAandproteinsareextracted,leavingRNAintheaqueoussupernatant.TheyieldoftotalRNAdependsonthetissueorcellsource,butitisgenerallyintherangeof4-7µg/mgstartingtissueor5-10µg/106cells.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol3:
SelectionofPoly(A)+RNAbyOligo(dT)-CelluloseChromatography
Chromatographyonoligo(dT)columnsisthepreferredmethodforlarge-scalepurification(>25µg)ofpoly(A)+RNAextractedfrommammaliancells.Typically,between1%and10%oftheRNAappliedtotheoligo(dT)columnisrecoveredaspoly(A)+RNA.Becausethemethodcanbefrustratinglyslow,itisnotrecommendedforpurificationofpoly(A)+RNAfrommultiplesamples.Forthispurpose,batchelution(Chapter7,Protocol4)isthebetterchoice.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol4:
SelectionofPoly(A)+RNAbyBatchChromatography
WhenmanyRNAsamplesaretobeprocessedorwhenworkingwithsmallamounts(<50µg)oftotalmammalianRNA,thetechniqueofchoiceisbatchchromatographyonoligo(dT)-cellulose.ThemethoddescribedinthisprotocolusesacombinationoftemperatureandionicstrengthtomaximizebindingandrecoveryofpolyadenylatedRNA.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol5:
SeparationofRNAAccordingtoSize:
ElectrophoresisofGlyoxylatedRNAthroughAgaroseGels
SeparationofRNAsaccordingtosizeisthefirststageinnorthernblottingandhybridization.ThemethoddescribedinthisprotocolusesglyoxaltodenaturetheRNA,ethidiumbromidetostainit,andagarosegelelectrophoresistoseparatetheresultingglyoxal-RNA-ethidiumadducts.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol6:
SeparationofRNAAccordingtoSize:
ElectrophoresisofRNAthroughAgaroseGelsContainingFormaldehyde
SeparationofRNAsaccordingtosizeisthefirststageinnorthernblottingandhybridization.ThemethoddescribedinthisprotocolusesformaldehydetodenaturetheRNA,ethidiumbromidetostainit,andelectrophoresisthroughagarosegelscontaining2.2Mformamidetoseparatetheresultingformaldehyde-RNA-ethidiumadducts.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol7:
TransferandFixationofDenaturedRNAtoMembranes
ThisprotocoldescribesthetransferofRNAfromagarosegelstoneutralorpositivelychargednylonmembranes,usingupwardcapillaryflowofneutraloralkalinebuffers.RNAbecomescovalentlyfixedtopositivelychargednylonmembranesduringtransferinalkalinebuffers.However,treatmentbyUVirradiationorheatingisrequiredtofixRNAtoneutralmembranes.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol8:
NorthernHybridization
Thisprotocoldescribeshowtocarryoutnorthernhybridizationathighstringencyinphosphate-SDS-buffers.Althoughawidevarietyofformatsareavailable,hybridizationisusuallyperformedinheat-sealablebags,rollerbottles,orplasticboxes,asdescribedhere.
IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol9:
DotandSlotHybridizationofPurifiedRNA
DotblottingofRNAisbestcarriedoutusingpurifiedpreparationsofRNAthataredenaturedwithglyoxalorformaldehydeimmediatelybeforeloadingontoanylonmembranethroughavacuummanifold.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol10:
MappingRNAwithNucleaseS1
PreparationsofRNAcontaininganmRNAofinterestarehybridizedtoacomplementarysingle-strandedDNAprobe.Attheendofthereaction,nucleaseS1isusedtodegradeunhybridizedregionsoftheprobe,andthesurvivingDNA-RNAhybridsarethenseparatedbygelelectrophoresisandvisualizedbyeitherautoradiographyorSouthernhybridization.ThemethodcanbeusedtoquantitateRNAs,tomapthepositionsofintrons,andtoidentifythelocationsof5´and3´endsofmRNAsonclonedDNAtemplates.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol11:
RibonucleaseProtection:
MappingRNAwithRibonucleaseandRadiolabeledRNAProbes
PreparationsofRNAcontaininganmRNAofinterestarehybridizedtoaradiolabeledsingle-strandedRNAprobe.Attheendofthereaction,amixtureofRNaseAandRNaseT1isusedtodegradeunhybridizedregionsoftheprobe,andthesurvivingmoleculesarethenseparatedbydenaturinggelelectrophoresisandvisualizedbyautoradiography.ThemethodcanbeusedtoquantitateRNAs,tomapthepositionsofintrons,andtoidentifythelocationsof5´and3´endsofmRNAsonclonedDNAtemplates.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Protocol12:
AnalysisofRNAbyPrimerExtension
Primerextensionisusedchieflytomapthe5´terminiofmRNAs.ApreparationofpolyadenylatedmRNAisfirsthybridizedwithanexcessofasingle-strandedoligodeoxynucleotideprimer,whichiscomplementarytothetargetRNAandradiolabeledatits5´terminus.Reversetranscriptaseisthenusedtoextendthe3´endoftheprimer.ThesizeoftheresultingcDNA,measuredbydenaturingpolyacrylamidegelelectrophoresis,isequaltothedistancebetweenthe5´endoftheprimingoligonucleotideandthe5´terminusofthetargetmRNA.
IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
Chapter7,Protocol1
PurificationofRNAfromCellsandTissuesbyAcidPhenol-GuanidiniumThiocyanate-ChloroformExtraction
Inthissingle-steptechnique,cellsarehomogenizedinguanidniumthiocyanateandtheRNAispurifiedfromthelysatebyextractionwithphenol:
chloroformatreducedpH.Manysamplescanbeprocessedsimultaneouslyandspeedily.TheyieldoftotalRNAdependsonthetissueorcellsourceandisgenerallyintherangeof4-7µg/mlstartingtissueor5-10µg/106cells.IMPORTANT:
PrepareallreagentsusedinthisprotocolwithDEPC-treatedH2O.
CAUTION
RECIPE
MATERIALS
BuffersandSolutions
Chloroform:
isoamylalcohol(49:
1,v/v)
Ethanol
Formamide(Optional)
DeionizedformamideisusedforthestorageofRNA.
Isopropanol
Liquidnitrogen
Phenol
PBS
Requiredforcellsgrowninsuspensionandmonolayersonly.
Sodiumacetate(2M,pH4.0)
SolutionD(denaturingsolution)
CellsandTissues
Mammaliancells
Mammaliantissuesamples
METHOD
1.PreparecellsortissuesamplesforisolationofRNAasappropriateforthematerialunderstudy.ThetablebelowdescribestheamountsofSolutionDrequiredforeachtypeofsample.
AmountofSolutionDRequiredtoExtractRNAfromCellsandTissues
AmountofTissue
orCells
Amountof
SolutionD
100mgoftissue
3ml
T-75flaskofcells
3ml
60-mmplateofcells
1ml
90-mmplateofcells
2ml
2.
Fortissues
a.
Isolatethedesiredtissuesbydissectionandplacethemimmediatelyinliquidnitrogen.
b.
Transferapprox.100mgofthefrozentissuetoamortarcontainingliquidnitrogenandpulverizethetissueusingapestle.Thetissuecanbekeptfrozenduringpulverizationbytheadditionofliquidnitrogen.
c.
Transferthepowderedtissuetoapolypropylenesnap-captubecontaining3mlofSolutionD.
d.
Homogenizethetissuefor15-30secondsatroomtemperaturewithapolytronhomogenizer.
3.Formammaliancellsgrowninsuspension
a.
Harvestthecellsbycentrifugationat200-1900g(1000-3000rpminaSorvallRT600usingtheH1000rotor)for5-10minutesatroomtemperatureinabenchtopcentrifuge.
b.
Removethemediumbyaspirationandresuspendthecellpelletsin1-2mlofsterileice-coldPBS.
c.
Harvestthecellsbycentrifugation,removethePBScompletelybyaspiration,andadd2mlofSolutionDper106cells.
d.
Homogenizethecellswithapolytronhomogenizerfor15-30secondsatroomtemperature.
4.Formammaliancellsgrowninmonolayers
a.
Removethemediumandrinsethecellsoncewith5-10mlofsterileice-coldPBS.
b.
RemovePBSandlysethecellsin2mlofSolutionDper90-mmculturedish(1mlper60mmdish).
c.
Transferthecelllysatestoapolypropylenesnap-captube.
d.
Homogenizethelysateswithapolytronhomogenizerfor15-30secondsatroomtemperature.
5.Transferthehomogenatetoafreshpolypropylenetubeandsequentiallyadd0.1mlof2Msodiumacetate(pH4.0),1mlofphenol,and0.2mlofchloroform-isoamylalcoholpermilliliterofSolutionD.Afteradditionofeachreagent,capthetubeandmixthecontentsthoroughlybyinversion.
6.Vortexthehomogenatevigorouslyfor10seconds.Incubatethetubefor15minutesonicetopermitcomple