DNAmethylationisanepigeneticmodificationthatplaysakeyroleinregulatingstemcells, developmentandmanydiseases.AbnormalDNAmethylationhasbeenobservedincancerformore thantwodecades,withmanyinvestigationsfocusingonpromoterhypermethylation,whichsilences tumorsuppressorgenes.Additionally,DNMT3A,oneofdenovoDNAmethyltransferases,is frequentlymutatedinaspectrumofhematologicalmalignancies.Ourlabhasdemonstratedthat Dnmt3alossimpairshematopoieticstemcell(HSC)differentiation,whileexpandingHSCnumbersin bonemarrow,suggestingDNMT3Amayhavearoleintumorigenesisandstemcellregulation. However,DNAmethylationprofilingofleukemiapatientsamplesshowsDNAmethylationcorrelates poorlywithgeneexpressionacrossthegenome,highlightingourlimitedunderstandingofthespecific functionsofDNAmethylation.RecentstudiesusingamurinemodelofthemostfrequentDNMT3A mutationinhematologicalmalignancies,DNMT3AR882,demonstratedthatDNMT3AR882cooperates withFLT3-ITDandNPM1cmutationstocontributetoleukemictransformation.Nevertheless,our knowledgeofwhichremainingDNMT3Amutationsleadtoleukemogenesisandthemechanismsby whichtheycontributetocancerformationremainslacking.Therefore,thelong-termgoalofthe proposedresearchistounderstandhowDNMT3Aaffectsgeneregulationincancer,andhow DNMT3Amutantspredisposestemcellexpansion.
In Aim1, IestablishedanovelDNAepigenome editingtool(dCas9-SunTag-DNMT3Asystem)toinvestigatethecausalrelationshipbetweenDNA methylationandgeneexpression.Usingpan-canceranalysisofgenome-wideprofiles,wehave identifiedDNAhypermethylationoccurringinthegene-bodyregionsofcanyons(broadand undermethylatedregions)withactivationofcorrespondinggeneexpression.
In Aim2, usinga Dnmt3amutantmurinemodelIdeveloped,IwillelucidatetheroleofoneDnmt3amutantinpriming stemcellexpansion.ThefindingsfromthisproposedresearchwillshedthelightonabnormalDNA methylationincancerandmolecularmechanismsofDNMT3A-associatedmalignancies.Littleis knownabouthowmutationsinepigeneticmodifiersaffectthe3Dgenomicstructureincancer. Therefore,inAim3,Iplantousemypostdoctoralstudiestounderstandhowepigeneticmodifiers shapethegenomiclandscapeincancerandtheirunderlyingmechanism.Thistrainingprogramis tailoredtogivemeacomprehensiveeducationinbasicscienceresearchthatwillbeextremelyuseful inachievingmylong-termcareergoalofbecominganindependentcancerresearcher.
DNA methylation, an epigenetic modification with widespread effects on gene expression, controls tissuespecificationduringdevelopment.AberrantDNAmethylationhasbeenobservedincancerfor more than two decades, however, the role of abnormal DNA methylation in tumor formation is still largely unclear. Previously, our lab has demonstrated that Dnmt3a loss impairs hematopoietic stem cell(HSC)differentiation,whileexpandingHSCnumbersinbonemarrow,indicatingpotentialrolesof Dnmt3a in HSC regulation. However, whether a hypomorphic mutation in Dnmt3a leads to hematopoietic stem/progenitor cell expansion is unknown. Here I propose to use a novel DNA epigenome editing tool developed during my graduate school studies to investigate the relationship betweenDNAmethylationandgeneexpression.IwillalsoelucidatetheroleofaspecificDnmt3ain stemcellexpansion.Theoverallgoalofthisresearchplanistouncovernoveltherapeutictargetsfor epigeneticmodifier-associateddiseases.
| Lei, Yong; Huang, Yung-Hsin; Goodell, Margaret A (2018) DNA methylation and de-methylation using hybrid site-targeting proteins. Genome Biol 19:187 |
| Brunetti, Lorenzo; Gundry, Michael C; Sorcini, Daniele et al. (2018) Mutant NPM1 Maintains the Leukemic State through HOX Expression. Cancer Cell 34:499-512.e9 |
| Su, Jianzhong; Huang, Yung-Hsin; Cui, Xiaodong et al. (2018) Homeobox oncogene activation by pan-cancer DNA hypermethylation. Genome Biol 19:108 |
| Huang, Yung-Hsin; Su, Jianzhong; Lei, Yong et al. (2017) DNA epigenome editing using CRISPR-Cas SunTag-directed DNMT3A. Genome Biol 18:176 |
| Lei, Yong; Zhang, Xiaotian; Su, Jianzhong et al. (2017) Targeted DNA methylation in vivo using an engineered dCas9-MQ1 fusion protein. Nat Commun 8:16026 |
