全基因组DNA甲基化分析(Method 上面一篇英文文献)

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UNCORRECTEDPROOF12WholegenomeDNAmethylationanalysisbasedonhighthroughput3sequencingtechnology

4NingLia,b,c,1,MingzhiYea,1,YingruiLia,1,ZhixiangYana,LeeM.Butchere,JihuaSuna,XuHana,5QuanChena,Xiuqingzhanga,JunWanga,d,*

6aBeijingGenomicsInstituteatShenzhen,Shenzhen518000,China

7bTheGraduateUniversityofChineseAcademyofSciences,Beijing100062,China

8cBeijingInstituteofGenomics,ChineseAcademyofSciences,Beijing100029,China

9dDepartmentofBiology,UniversityofCopenhagen,Copenhagen,Denmark

10eUCLCancerInstitute,PaulO’GormanBuilding,UniversityCollegeLondon,72HuntleyStreet,LondonWC1E6BT,UK

1113articleinfo

14Articlehistory:

15Accepted15April2010

16Availableonlinexxxx

17Keywords:

18DNAmethylation

19Bisulfite-sequencing

20MeDIP-sequencing

21MBD-sequencing

22

23abstract24TherearenumerousapproachestodecipherawholegenomeDNAmethylationprofile(‘‘methylome”),25eachvaryingincost,throughputandresolution.Thegoldstandardofthesemethods,wholegenomebisul-26fite-sequencing(BS-seq),involvestreatmentofDNAwithsodiumbisulfitecombinedwithsubsequent27highthroughputsequencing.UsingBS-seq,wegeneratedasingle-base-resolutionmethylomeinhuman28peripheralbloodmononuclearcells(inpress).ThisBS-seqmapwasthenusedasthereferencemethylome29tocomparetwoalternativesequencing-basedmethylomeassays(performedonthesamedonorof30PBMCs):methylatedDNAimmunoprecipitation(MeDIP-seq)andmethyl-bindingprotein(MBD-seq).In31ouranalysis,wefoundthatMeDIP-seqandMBD-seqarecomplementarystrategies,withMeDIP-seqmore32sensitivetohighlymethylated,high-CpGdensitiesandMDB-seqmoresensitivetohighlymethylated,33moderate-CpGdensities.Takingintoaccountthesizeofamammaliangenomeandthecurrentexpense34ofsequencing,wefeel3gigabases(Gbp)45bppaired-endMeDIP-seqorMBD-sequniquelymappedreads35istheminimumrequirementandcost-effectivestrategyformethylomepatternanalysis.36Ó2010ElsevierInc.Allrightsreserved.

3738391.Introduction40CytosineDNAmethylationisamajorepigeneticsystemthat41modifiestheDNAmoleculeitself.Ineukaryotes,DNAmethylation42isinvolvedindiverseprocesses,includingembryogenesis,genomic43imprinting,X-inactivationandtumorigenesisinmammals,and44transposonsilencinginplants[1–4].Inplantcells,methylated45cytosine(5mC)occursinCG-(CpG),CHG-andCHH-contexts[5].46Inmammaliansomatictissues,DNAmethylationoccursalmost47exclusively(99.98%)atCpGdinucleotides[6,7];recentevidence48inhumanembryonicstemcells,however,hasshownthatnearly49one-quarterofall5mCoccursatnon-CpGs,particularlywithin50genebodies[8].51AdetailedexplorationoftheroleofDNAmethylationindiverse52cellularprocessesrequiresaccurateandsensitivemethods,of53whichseveralgenome-wideandwholegenomeassaysexist.Gen-54ome-widemethodsincludecombiningenrichment-basedtech-55niquessuchasmethylatedDNAimmunoprecipitation(MeDIP)56andMethyl-BindingDomain(MBD)proteinwithmicroarrays

57(chips).MeDIPusesanantibodythatrecognizes5mCtopulldown58themethylatedfractionofagenome,whileMBDexploitsMECP2’s59affinityforCpGs.MeDIP-chipandMBD-chiphavebeenusedinde-60pendentlybyseveralgroupstostudyDNAmethylationatagen-61ome-widescaleinbothplant[9]andhumancells[10,11].62Withtheadventofnextgenerationsequencing,manyestab-63lishedmethodsofgenomeinterrogationwereupscaled.Logically,64MeDIPwaspromotedfrommicroarraystonextgeneration65sequencing:theresult,MeDIP-seq,continuestoenrichforse-66quencescontaining5mCbutisnolongerlimitedtoelucidating67methylationatlocitiledbyoligonucleotidesonamicroarray,and68hasbeenusedinplantgenomics[12],aswellaschartingthefirst69mammalianmethylome[13].Similarly,MBDhasbeencombined70withnextgenerationsequencingandrecently,threeisogeniccan-71cercelllineswerestudiedusingwhattheauthorsterm,MBD-iso-72latedGenomeSequencing[MiGS;14].73Anothermethod,reducedrepresentationbisulfite-sequencing74[15],usesenzymaticdigestiontoreducegenomecomplexityfol-75lowedbysubsequentbisulfitetreatmentandnextgeneration76sequencing.BecausetreatmentofDNAwithsodiumbisulfitecon-77vertsallunmethylatedcytosinestouracils,butleavesmethylated78cytosinesunchanged(albeitwithoutthemethylgroup)[16],

1046-2023/$-seefrontmatterÓ2010ElsevierInc.Allrightsreserved.doi:10.1016/j.ymeth.2010.04.009

*Correspondingauthorat:BeijingGenomicsInstituteatShenzhen,Shenzhen518000,China.Fax:+8675525273796.E-mailaddress:wangj@genomics.org.cn(J.Wang).1Theseauthorscontributedequallytothiswork.

Methodsxxx(2010)xxx–xxxContentslistsavailableatScienceDirectMethods

journalhomepage:www.elsevier.com/locate/ymeth

YMETH2589No.ofPages10,Model5G4May2010

Pleasecitethisarticleinpressas:N.Lietal.,Methods(2010),doi:10.1016/j.ymeth.2010.04.009