MolecularPsychiatry200164614642001NaturePublishingGroupAllrightsreserv - PDF document

1 MolecularPsychiatry(2001)6,461±464Ó2001N
MolecularPsychiatry(2001)6,461±464Ó2001NaturePublishingGroupAllrightsreserved1359-4184/01$15.00 www.nature.com/mp ORIGINALRESEARCHARTICLE Voltage-gatedcalciumchannelg2subunitgeneisnotdeletedinvelo-cardio-facialsyndromeJLBlackIII1,LEKrahn1,2andSMJalal31DepartmentofPsychiatryandPsychology;2DivisionofPulmonaryMedicine;3DepartmentofLaboratoryMedicineandPathology,MayoClinicandFoundation,Rochester,MN55905,USAKeywords:velo-cardio-facialsyndrome;schizophrenia;link- Velo-cardio-facialsyndromeandVGCCg2 JLBlackIIIetal 462 MolecularPsychiatry Figure1(aandb)Metaphasespreadofapatientwithvelo-cardio-facialsyndromeandschizophrenia.(a)FISHprobeforg2exon1,whichwasmadebybiotin-16-dUTPlabelingofPACdJ293L6.(b)FISHprobeforg2exon3and4,whichwasmadebybiotin-16-dUTPlabelingofPACdJ1119A7.Ineachdiagrambothchromosomes22hybridizedwiththeprobeandproducedasignalindicatingthattheg2geneisnotdeletedeventhoughtheVCFSFISHprobe,TUPLE1,wasdeletedononeofthechromosomes(datanotshown).TheotherfourVCFSpatientsandfourcontrolsgaveidenticalresultsfortheg2gene.(Imageswerealteredtoagrayscalefromacolorprintforpublicationpurposes.)WechosetostudytheVGCCg2subunitgeneinVCFSeventhoughitistelomerictothemostcommonVCFSdeletionregion,forthefollowingreasons:(1)VGCCaremolecularlydiverseheteromultimericchannelscomprisedofthea1subunit,whichcon-tainsthevoltagesensingregionandionpore;absubunit,whichregulatesactivationproperties,steady-stateinactivation,inactivationkineticsandpeakcurrent;ana2dsubunit,whichregulatesthekineticsofcurrentinactivationandthenumberofchannelsavailableinthemembrane;andagsub-unit,whichproducesalowerrestingpotentialforcalciumchannels,thusreducingtheavailabilityofthecalciumchannelsforactivation.20±22VGCCsub-unitmutationshavebeenshowntobeclinicallyrelevantinhumans.InstabilityintheCAGrepeat,foundinthea1Asubunit,hasbeenassociatedwith Figure2Schematicrepresentationofchromosome22.This®gureshowstheestimated59locationsofthemostcommonVCFSdeletionsite(19.28±22.88Mb),theVGCCg2subunitgene(37.16Mb),TUPLE1probe(22.50Mb),ARSAprobe(47.54Mb),andtheputativeschizophreniamarker,D22S278(36.72Mb).TheVCFSdeletionsitecanbesmaller,larger,orundetectableandacaseofVCFSassociatedwithabalanced(21;22)(p12;q11)translocationhasbeendescribed.16,17,19spinocerebellarataxiatype6(SCA6).23OnecaseofSCA6withschizophreniaanddementiahasbeendescribed.24Additionalmutationsinthea1Asub-unithavealsobeenlinkedtoepisodicataxiatype2andfamilialhemiplegicmigraine.23Amutationinthea1Ssubunitcauseshypokalemicperiodicparalysis.23Malignanthyperthermiahasbeenasso-ciatedwithamutationofthea2dsubunit.23(2)Theg2subunitisrelevanttoschizophreniaresearchbecauseelectrophysiologicstudieshaveshownthattheg2geneproductreducescalciumchannelrestingpotentialthusstabilizingthecal-ciumchannel.21Wespeculatethatamutationoftheg2subunitgeneinhumanscouldhaveeithertheeffectofincreasingordecreasingVGCCcalciumpermeability.Achangeineitherdirectioncouldconceivablycausepsychosisbyincreasingneuro-transmissionofpsychogenicneurotransmittersorbysettingoffacas

2 cadeofintracellulareventswhichcouldeffec
cadeofintracellulareventswhichcouldeffectsynaptogenesis.21,23Supportforthisstatementcomesfromdatathatnormalcal-ciumchannelfunctionisneededfornormalneu-ronalcellmigrationduringembryogenesis.Theg2genehasbeenimplicatedinthisprocessinthestar-gazermouselinewhereamutationoftheg2genecausesseizuresandneuroanatomicabnormalities.Inthesemice,cerebellardisordershavebeendescribed,includingabnormalmigrationandmatu-rationandreducedbrain-derivedneurotrophicfac-torproductionofcerebellargranulecells.25,26Abnormalsynaptictransmissionhasalsobeendescribed,suggestingacrucialroleoftheg2pro-teinfornormalsynaptictransmissionorsynapto-genesis.27,28Furthermore,aportionofthebrainmorerelevanttoschizophreniahasbeenimpli-catedinthattheexpressionofg2ismuchreduced Velo-cardio-facialsyndromeandVGCCJLBlackIIIetal inhippocampalregionCA3instargazermice.Finally,ourownunpublisheddatarevealthatthe2subunitisexpressedthroughoutthehumanbrain,especiallythecortex(Black,unpublished(3)Therelativeproximityonchromosome22(seeFig-ure2)ofthe2gene(at37.16Mb)totheputativemarkerforschizophrenia,D22S278(at36.72Mb),makesthe2subunitgenearelevantgenetostudyinschizophrenicswithorwithoutVCFS.(4)Finally,thepreviouslymentionedvariabilityinthedeletionsizesledustospeculatethatthosepatientswithVCFSandschizophreniamayhaveanasyetundetecteddeletionofgenesintheD22S278region,includingthe2subunitgene.Oursamplesizewassmallbutourinvestigationfoundnoevidencethatthe2genewasdeletedinVCFSwithorwithoutschizophrenia,whichmakesadeletionofthe2geneetiologictoschizophreniainVCFSunlikely.Ourstudydidnotaddressthepossi-bilitythatthe2activitymaybechangedbyregionaleffectsoftheVCFSdeletionandwedidnotde®netheexactboundariesofthedeletioninourpatients.Thepossibilitythataspeci®c2genepolymorphismormutationcouldinteractwiththedeletionassociatedwithVCFSwasalsonotaddressedinthisresearch.Insummary,usingFISH,weshowedthatthe2genewasnotdeletedinVCFSwithorwithoutschizo-phrenia.However,the2genemaystillbearelevantcandidategeneforsusceptibilitytoschizophreniaduetoitsproximitytothemarkerD22S278thathasbeenlinkedtoschizophreniainsomestudies.ThisworkwassupportedbygrantsfromtheMayoCan-cerCenterandtheMayoClinicandFoundation.IRBapprovalThisstudywasreviewedandapprovedbytheMayoClinicInstitutionalReviewBoard(IRB)andconsentrequirements,asdeterminedbytheIRB,weremetbeforethepatientswereenrolledinthestudy.HumansubjectsWeexaminedthemetaphasespreadsoffourpatientswithVCFSwithoutapparentschizophreniaby¯uor-insituhybridization(FISH).Inaddition,westudiedonepatientseenattheclinicwithknownVCFSandschizophrenia.Thelatterpatienthasbeenthesubjectofacasereportandhasbeenwellcharac-terizedashavingschizophrenicsymptoms.healthysubjectswerestudiedascontrols.Todetectdeletionsinthe2gene(whichcontainsfourexons)frommetaphasespreadsofpatientswithVCFS,wemadetwoFISHprobes.OneprobecontainedDNA MolecularPsychiatryencodingthe®rstexonofthe2geneandtheotherprobewasspeci®ctothethirdandfourthexons.Exon1wasencodedinPACRPCI1(dJ293L6)andexons3and4wereencodedinPACRPCI5(dJ1119A7).Bo

3 thofthesePACsaresubclonedintothecCYPAC2v
thofthesePACsaresubclonedintothecCYPAC2vectorwhichwerecarriedinanE.colistrainandwereobtainedfromtheSangerInstitute.ThesePACsweretestedfortheappropriateexonsbydoingPCRwithprimersspeci®cforexon1(G15GTTTGATCGA,G33andexon4(G12GACCGGCACAAACA,G15TTATACGGGGGTGGTCCG).PCRparameterswereCfor1minforonecycle,then95Cfor1min,55for1min,68Cfor1minfor30cycles,then4Csoak.Singlebandsoftheexpectedsizeon1.5%agarosegels(203bpand366bp,respectively)wereobserved(datanotshown)whichcon®rmedthepresenceoftheinsert.PACswerepuri®edfrom25gmlLBbacterialcul-turesviaminipreps(Qiagen,Venlo,TheNetherlands)andwerelabeledwithbiotin-16-dUTP(RocheGroup,Basel,Switzerland)usinganicktranslationprocedure(GibcoBRL,Rockville,MD,USA).TheFISHprobefordetectionofVCFSwasnamedTUPLE1and¯uorescesthe22q11.2regioninorange.The110-kbTUPLE1probecontainsD22S533,D22S609,andD22S942.Acontrolprobe,calledARSA(arylsulfataseA),¯uor-escesthe22q13.33regiongreenandislocatedoutsideoftheVCFSdeletionregion(bothprobeswereobtainedfromVysis,DownersGrove,IL,USA).TheprocedureforFISHwasaspreviouslydescribed.MappingofthelocationsoftheVGCC2subunitgene,TUPLE1,ARSA,theVCFSdeletionsites,andtheputa-tiveschizophreniamarker,D22S278,weredoneusingtheNationalCenterforBiotechnologyInformation(NCBI)HumanGenomeResourceswebsitesatOligonucleotidesynthesisandsequencingwascon-ductedintheMayoClinic'sCorefacilities.FISHwasconductedintheMayoClinicCytogeneticsLaboratory.1PulverA,NestadtG,GoldbergR,ShprintzenR,LamaczM,Woly-niecPetal.Psychoticillnessinpatientsdiagnosedwithvelo-car-dio-facialsyndromeandtheirrelatives.JNervMentDis2ChowE,MikulisD,ZipurskyR,ScuttL,WeksbergR,BassettA.QualitativeMRI®ndingsinadultswith22q11deletionsyndromeandschizophrenia.BiolPsychiatry:1436±1442.3McCarleyR,WibleC,FruminM,HirayasuY,LevittJ,FischerI.MRIanatomyofschizophrenia.BiolPsychiatry:1099±4LindsayE,MorrisM,GosA,NestadtG,WolyniecP,LasseterV.Schizophreniaandchromosomaldeletionswithin22q11.2.JMedGenet:1502±1503.5BlackJ,LennonV.Theidenti®cationandcloningofputativehumanneuronalvoltage-gatedcalciumchannel2and3sub-units:neurologicalimplications.MayoClinProc:357±6GillM,ValladaH,CollierD,ShamP,HolmansP,MurrayRetal Velo-cardio-facialsyndromeandVGCC JLBlackIIIetal 464 MolecularPsychiatryAcombinedanalysisofD22S278markerallelesinaffectedsib-pairs:supportforasusceptibilitylocusforschizophreniaatchro-mosome22q12.SchizophreniaCollaborativeLinkageGroup(Chromosome22).AmJMedGenet:40±45.7Anonymous.AtransmissiondisequilibriumandlinkageanalysisofD22S278markerallelesin574families:furthersupportforasusceptibilitylocusforschizophreniaat22q12.SchizophreniaCol-laborativeLinkageGroupforChromosome22.SchizophrRes:115±121.8CrifasiP,MichelsV,DriscollD,JalalS,DewaldG.DNA¯uorescentprobesfordiagnosisofvelocardiofacialandrelatedsyndromes.MayoClinProc:1148±1153.9PulverA,KarayiorgouM,WoyniecP,LasseterV,KaschL,Nestadtetal.Sequentialstudytoidentifyasusceptibilitygeneforschizo-phrenia:reportofpotentiallinkageonchromosome22q12±13.1:Part1.AmJMedGenet:36±43.10LasseterV,PulverA,WolyniecP,Nesta

4 dtG,MeyersD,Karayior-gouMetal.Follow-upr
dtG,MeyersD,Karayior-gouMetal.Follow-upreportofpotentiallinkageforschizophreniaonchromosome22q:Part3.AmJMedGenet:172±173.11PulverA,KarayiorgouM,LasseterV,WoyniecP,KaschL,Antona-rakisSetal.Follow-upofareportofapotentiallinkageforschizo-phreniaonchromosome22q12±13.1:Part2.AmJMedGenet:44±50.12PulverA.Searchforschizophreniasusceptibilitygenes.BiolPsy-:221±230.13BrzustowiczL,HodgkinsonK,ChowE,HonerW,BassettA.Locationofamajorsusceptibilitylocusforfamilialschizophreniaonchromosome1q21±q22.:678±682.14DunhamI,ShimizuN,RoeB,ChissoeS,HuntA,CollinsJetalTheDNAsequenceofhumanchromosome22.15KrahnL,MaraganoreD,MichelsV.Childhood-onsetschizophreniaassociatedwithparkinsonisminapatientwithamicrodeletionofchromosome22.MayoClinProc:956±959.16CarlsonC,PapolosD,PanditaR,FaeddaG,VeitS,GoldbergR.Molecularanalysisofvelo-cardio-facialsyndromepatientswithpsychiatricdisorders.AmJHumGenet:851±859.17EdelmannL,PanditaR,SpiteriE,FunkeB,GoldbergR,Palanisamyetal.Acommonmolecularbasisforrearrangementdisordersonchromosome22q11.HumMolecGenet:1157±1167.18KarayiourgouM,GogosJ,GalkeB,JefferyJ,NestadtG,WolyniecPetal.Genotypeandphenotypeanalysisatthe22q11schizophreniasusceptibilitylocus.ColdSpringHarbSympQuantBiol19HolmesS,RiaziM,GongW,McDermidH,SellingerB,HuaA.Disruptionoftheclathrinheavychain-likegene(CLTCL)asso-ciatedwithfeaturesofDGS/VCFS:abalanced(21;22)(p12;q11)HumMolecGenet:357±367.20DavilaH.Molecularandfunctionaldiversityofvoltage-gatedcal-ciumchannels.AnnNYAcadSci:102±117.21LettsV,FelixR,BiddlecomeG,ArikkathJ,MahaffeyC,Valenzuelaetal.ThemousestargazergeneencodesaneuronalCagammasubunit.NatureGenet:340±347.22RoussetM,CensT,RestituitoS,BarrereC,BlackJLIII,McEneryetal.Functionalrolesof3and4,threenewCasubunits,onP/QtypeCachannelexpressedinJPhysiol)2001;(inpress).23BurgessD,NoebelsJ.Voltage-dependentcalciumchannelmutationsinneurologicaldisease.AnnNYAcadSci24TashiroH,SuzukiS,HitotsumatsuT,IwakiT.Anautopsycaseofspinocerebellarataxiatype6withmentalsymptomsofschizo-phreniaanddementia.ClinNeuropathol:198±204.25QiaoX,HeftiF,KnuselB,NoebelsJ.Selectivefailureofbrain-derivedneurotrophicfactormRNAexpressioninthecerebellumofstargazer,amutantmousewithataxia.JNeurosci:640±26QiaoX,ChenL,GaoH,BaoS,HeftiF,ThompsonRetal.Cerebellarbrain-derivedneurotrophicfactor-TrkBdefectassociatedwithimpairmentofeyeblinkconditioninginstargazermutantmice.:6990±6999.27ChenL,BaoS,QiaoX,ThompsonR.Impairedcerebellarsynapsematurationinwaggler,amutantmousewithadisruptedneuronalcalciumchannelgammasubunit.ProcNatlAcadSciUSA:12132±12137.28HashimotoK,FukayaM,QiaoX,SakimuraK,WatanabeM,KanoM.ImpairmentofAMPAreceptorfunctionincerebellargranulecellsofataxicmutantmousestargazer.JNeurosci29SharpA,DubelS,BlackJI,SundarrajS,ShenJ-P,CopelandT.Stargazermutationrevealsregionalspecializationinexpressioninmousebrain.2001;(inpress). Correspondence:JLBlackIIIMD,MayoClinic,DepartmentofPsy-chiatryandPsychology,200SW1stStreet,Rochester,MN55905,USA.E-mail:black.johnReceived14August2000;revised12December2000;accepted14December200