染色質(zhì)修飾及其作用機(jī)理

染色質(zhì)修飾及其作用機(jī)理DNAPackingDNA—2nm，核小體串珠—11nm，染色質(zhì)纖維—30nm，染色質(zhì)高級(jí)環(huán)狀結(jié)構(gòu)—300-700nm，間期染色體—1400-1500nm。染色質(zhì)的高級(jí)結(jié)構(gòu)

1.如何將10,000公里長(zhǎng)的蠶絲(半徑~10-5米)裝入一個(gè)籃球中。

2.蠶絲的體積：3.14*10-3m3

3.折疊、纏繞…DNAPacking染色質(zhì)的高級(jí)結(jié)構(gòu)OrganizationofDNAWithinaCellfromLodish

etal.,MolecularCellBiology,6thed.Fig6-12metersofDNAispackedintoa10mmdiametercell核小體結(jié)構(gòu)染色質(zhì)模板2.8?的核小體模型（左），X射線(xiàn)晶體衍射核小體結(jié)構(gòu)（中），組蛋白核心八聚體被DNA盤(pán)繞結(jié)構(gòu)的圖示（右）。組蛋白尾部從核小體表面伸出。核小體結(jié)構(gòu)Histonevariants組蛋白修飾活化修飾：乙酰化，精氨酸甲基化，賴(lài)氨酸甲基化（H3K4，H3K36，H3K79）。抑制修飾：賴(lài)氨酸甲基化（H3K9，H3K27，H4K20）。組蛋白尾巴的修飾位點(diǎn)組蛋白修飾與修飾酶（1）組蛋白修飾與修飾酶（2）主要的功能基團(tuán)AcetylMethylPhosphorylUbiquitinEpigeneticdifferences：monozygotictwins

DifferentialDNAmethylationbetweenMZtwinsusingAIMS.(ALeft)ExampleofanAIMSanalysisin3-and50-year-oldtwinpairs.DifferentialbandscorrespondingtoDNAmethylationareindicatedwitharrows.(ARight)NumberofdifferentialbandsobtainedbyAIMSin3-and50-year-oldtwinpairs.(B)

Bisulfitegenomicsequencingof12clonesoftherepetitiveDNAsequenceAlu-SPobtainedbyAIMSin3-and50-year-oldtwinpairs.SchematicrepresentationsofthemethylationstatusofeachCpG

dinucleotide.Blackandwhitedotsindicatemethylatedandunmethylated

CpGs,respectively.Epigeneticdifferences：monozygotictwins

MappingchromosomalregionswithdifferentialDNAmethylationinMZtwinsbyusingcomparativegenomichybridizationformethylatedDNA.Examplesofthehybridizationofchromosomes1,3,12,and17aredisplayed.The50-year-oldtwinpairshowsabundantchangesinthepatternofDNAmethylationobservedbythepresenceofgreenandredsignalsthatindicatehypermethylationandhypomethylationevents,whereasthe3-year-oldtwinshaveaverysimilardistributionofDNAmethylationindicatedbythepresenceoftheyellowcolorobtainedbyequalamountsofthegreenandreddyes.SignificantDNAmethylationchangesareindicatedasthickredandgreenblocksintheideograms.Epigeneticdifferences：monozygotictwins

(Upper)Quantificationofglobal5mCDNAcontent(Left),histoneH4acetylation(Center),andhistoneH3acetylation(Right)byHPLCandhigh-performancecapillaryelectrophoresis.(Lower)Comparisonofepigeneticvaluesbetweenthesiblingsofeach3-and50-year-oldtwinpair.FragaMF,

ProcNatl

Acad

SciUSA.2005,26;102(30):10604–10609內(nèi)容提要

一、組蛋白的乙?；?/p>

二、組蛋白的甲基化

三、組蛋白的磷酸化

四、組蛋白的泛素化

五、組蛋白的SUMO化

六、組蛋白密碼一、組蛋白的乙酰化一、組蛋白的乙?；阎M蛋白乙酰化位點(diǎn)一、組蛋白的乙?；M蛋白乙?；D(zhuǎn)移酶-HATsGcn5/PCAF&p300/CBPBromodomain1.Anacetyl-lysinebindingdomain2.HATs修飾底物之后可能與底物上的乙?；?lài)氨酸結(jié)合HATs:MYST(MOZ-Ybf2/Sas3-Sas2-TIP60)HAT識(shí)別底物的分子機(jī)制NucleicAcidsRes,2004,3:

959-976人類(lèi)IFN-β基因的激活TheDNAcodecontainsalltheinformationfortheassemblyoftheenhanceosomeinresponsetovirusinfection.DNAcodeinformationprocessing.TheenhanceosomerecruitstheGCN5histone

acetyltransferase.(CandD)GCN5acetylatesinitiallyH4K8andH3K9(C).Anunknownkinaserecruitedbytheenhanceosome

phosphorylatesH3Ser10,aprerequisiteforH3K14acetylationbyGCN5(D).Thehistonecodeisprinted.(E)Translationofthehistonecode.ThebromodomaincontainingtranscriptioncomplexesSWI/SNFandTFIIDarerecruitedtothepromoterviabivalentinteractionsbetweentheenhanceosomeandspecificallyacetylatedhistoneNtermini.Cell.2002Nov1;111(3):381-92.蛋白質(zhì)乙酰化調(diào)控基因轉(zhuǎn)錄Transcriptionfactors(TF)canbeacetylated(indicatedbyaflag)byhistone

acetyltransferase(s)(HAT),andthisacetylationincreasesthebindingofTF(suchasp53,seetext)toaDNAsequence.TheactivationdomainofTFcanrecruitaHATcomplextothepromoter.TheHATcomplexthenacetylatestherelevantresiduesofthehistonetailsto‘open’upthechromatin.The‘open’chromatinallowsthebasaltranscriptionmachinery(BTM)tobindandinitiatetranscription.Later,HATs,co-activatorsorotherfactorsintheHATcomplexareacetylatedbyaregulatoryHAT.Afteracetylation,theHATcomplexlosesitsaffinityfortheTFandthusdissociates.Eventually,thedecreaselevelofboundHATcomplex‘closes’thechromatinanddecreasestranscription.Theflagsymbolindicatesacetylation.CurrentOpinioninCellBiology2000,12:326–333組蛋白修飾與DNA損傷修復(fù)Fernandez-CapetilloO,NussenzweigAPNAS2004;101:1427-1428rDNA損傷修復(fù)：A.Homologousrecombination(HR)B.Nonhomologousend-joining(NHEJ)

A.完整的DNA序列；

B.雙鏈斷裂；C.NHEJ因子:(D)修復(fù)因子與(E)染色質(zhì)重塑因子；紅色：磷酸化，藍(lán)色：乙酰化，黃色：去乙?；?；F.染色質(zhì)重塑的構(gòu)型，(G)增大NHEJ局部濃度；

H.直至修復(fù)HDACsr

Histone

deacetylases(HDACs)catalysetheremovalofacetylgroupsfromlysineresiduesinhistoneaminotermini,leadingtochromatincondensationandtranscriptionalrepression.

EighteenHDACshavebeenidentifiedinhumans,andtheyaresubdividedintofourclassesbasedontheirhomologytoyeastHDACs,theirsubcellularlocalizationandtheirenzymaticactivities.NatureReviewsDrugDiscovery

2006,

5,769-784

HDACsr

TheclassIHDACs(1,2,3and8)arehomologoustotheyeastRPD3protein,cangenerallybedetectedinthenucleusandshowubiquitousexpressioninvarioushumancelllinesandtissues.

ClassIIHDACs(4,5,6,7,9and10)sharehomologieswiththeyeastHda1proteinandcanshuttlebetweenthenucleusandthecytoplasm.HDACsrTheclassIIIHDACs(SIRT1,2,3,4,5,6and7)arehomologuesoftheyeastproteinSir2andrequireNAD+fortheiractivitytoregulategeneexpressioninresponsetochangesinthecellularredoxstatus.HDAC11isthesolememberoftheclassIVHDACs.ItsharessequencesimilaritywiththecatalyticcoreregionsofbothclassIandIIenzymes.HDACsrHDACs目的：從我們特有的雜多酸化合物庫(kù)(近400種)中篩選得到高活性、特異性的HDI；研究其抗瘤活性及機(jī)制。雜多酸的篩選和鑒定：(A).13種能增強(qiáng)報(bào)告基因表達(dá)的雜多酸;(B).PAC-320對(duì)HDAC活性的抑制作用;(C)PAC-320抑制胞內(nèi)HDAC活性，濃度依賴(lài)的上調(diào)胞內(nèi)組蛋白H3乙?；健AC-320（μM）15105NaBconAc-H3actinPC3DU145LNCaPAc-H3Ac-H3actinactinABC新型組蛋白去乙?；敢种苿┑暮Y選及其抗癌活性研究雜多酸PAC-320在體外對(duì)多種腫瘤細(xì)胞有抑制作用（如結(jié)腸癌SW620、胃癌MGC-803、肺癌A549、乳腺癌MM-231和肝癌HepG2）。雜多酸PAC-320在體外對(duì)腫瘤細(xì)胞有較強(qiáng)的抑制作用（肝癌HepG2），而對(duì)正常細(xì)胞（肝上皮細(xì)胞L-02）毒性較小。ABCPAC-320抑制體內(nèi)DU145腫瘤的生長(zhǎng)：(A)PA-320對(duì)腫瘤體積的影響；(B)PA-320對(duì)腫瘤重量的影響；（C）PA-320小鼠體重的影響PAC-320對(duì)裸鼠體內(nèi)移植腫瘤（DU145）的抑制作用申請(qǐng)的發(fā)明專(zhuān)利：1）組蛋白去乙?；敢种苿┯袡C(jī)錫多酸化合物及其制備方法，專(zhuān)利公開(kāi)號(hào):CN101139368。2）p21WAF1啟動(dòng)子報(bào)告基因組蛋白去乙?；敢种苿┖Y選模型的構(gòu)建及其應(yīng)用，專(zhuān)利公開(kāi)號(hào)：CN101275157。PAC-320濃度依賴(lài)的抑制前列腺癌細(xì)胞（LNCaP：AR-positive；DU145：AR-negative）周期停滯在G2/M期(A)，同時(shí)上調(diào)p21(B,LNCaP;C,DU145)的表達(dá)水平。PA-320濃度依賴(lài)的誘導(dǎo)前列腺癌凋亡：(A)，AnnexinV染色；(B)LNCaP,(C)DU145中活化的caspase3/7表達(dá)水平上調(diào)。(JMedChem,submitted)乙酰化和去乙?；D(zhuǎn)錄因子招募HDACs抑制基因表達(dá)

轉(zhuǎn)錄因子招募HATs復(fù)合物激活基因表達(dá)乙?；腿ヒ阴；D(zhuǎn)錄因子招募HDACs抑制基因表達(dá)

轉(zhuǎn)錄因子招募HATs復(fù)合物激活基因表達(dá)二、組蛋白甲基化精氨酸和賴(lài)氨酸甲基化過(guò)程賴(lài)氨酸甲基化賴(lài)氨酸甲基化的功能賴(lài)氨酸甲基化酶（HKMTs）Yeast,redWorm,yellow

Fly,pinkMammalian,purple

NatureReviewsMolecularCellBiology

2005,

6,838-849

HKMTsNatureReviewsMolecularCellBiology

2005,

6,838-849

ThePRMTs1–8allhaveaconservedAdoMetbindingdomain(shadedingrey)withtheconservedmotifsI,postI,II,andIII,andalessconservedsubstratebindingdomain(lightgrey).PRMTs生物學(xué)功能MAPK激酶在細(xì)胞外信號(hào)的刺激下活化MSK1和MSK2激酶，導(dǎo)致H3Ser10磷酸化，活化c-fos和c-jun基因表達(dá)。IKKa激酶活化后導(dǎo)致H3Ser10磷酸化，激活NF-kB表達(dá)。HISTONE-CODEHYPOTHESIS：TheHistoneCodeishypothesizedtobeacodeconsistingofcovalenthistonetailmodifications.TogetherwithothermodificationssuchasDNAmethylationitispartoftheepigeneticcode.Ahypothesisthatproposesthatdistincthistonemodifications,ononeormoretails,functionsequentially,orincombination,todefineacodethatistranslatedbyeffectorproteinswithspecificbiologicalfunctions.

Comprehensiveanalysessuggestthatratherthanconstitutingageneralcode,thecovalentmodificationsofproteins(includinghistones)providesurfacesthatarerecognizedbyeffectorsthatcangiverisetointricateinteractionsanddownstreamevents.Thesearereminiscentofotherregulatoryca