New stem cell maintenance protein found

韩雪娜

日期: 2002-12-02 今日/总浏览: 1/696
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Ronald D.G. McKay, Ph.D.; N" r+ s0 K  r0 f( ]/ X
Scientistshaveidentifiedacritical,newstemcellprotein?amarkedadvanceintheelucidationofthemolecularblueprintofstemcells.
) Y' X/ @/ S8 L4 X# K/ B& `4 ^Drs.RobertTsaiandRonaldMcKayattheNIHhavediscoveredanovelgene,callednucleostemin,whoseencodedproteinisnecessaryformaintainingtheproliferativecapacityofembryonicandadultstemcells,andpossiblysometypesofcancercells.TheirreportispublishedintheDecember1issueofthescientificjournalGenes&Development.# `5 _9 p# I, Y1 A: e
Embryonicstemcellsarepluripotentprogenitorcellsthatcandifferentiateintoallofthecelltypesofthebody.Adultstemcells,incontrast,havealessversatilepotential:Theirdifferentiationisgenerallyrestrictedtothecelltypesofaspecifictissue(althoughrecentworkhasexpandedthepreviouslyknownrangeofadultstemcelldifferentiationpotential).
( o* L7 C7 k4 I4 }( gAkeyfeatureofbothembryonicandadultstemcellsistheircapacityforself-renewalaswellasdifferentiation?ensuringthataconstantpoolofundifferentiatedstemcellsalwaysexists.Drs.TsaiandMcKayhaveidentifiednucleosteminasacriticalregulatorofthisdelicatebalance.- Q& b, {5 K* t1 ]9 b  M
Drs.TsaiandMcKayoriginallyidentifiednucleosteminasaproteinabundantlyexpressedinratCNS(centralnervoussystem)stemcellsthatismarkedlydown-regulatedduringdifferentiation,suggestingapossibleroleinstemcellmaintenance.Theresearcherswentontoshowthatnucleosteminisexpressedinvariousadultandembryonicstemcellpopulations,aswellasinsomehumancancercelllines,andthatitsexpressionisconsistentlyturned-offduringthedifferentiationofstemcellsintomorespecializedcelltypes.# |- x% R( K; F+ F1 H) @& C. {6 Q/ r
UsingtheRNAigenesilencingmethod,Drs.TsaiandMcKaydisruptednormalnucleosteminexpressionpatternsinrodentCNSstemcellsandhumanosteosarcomacancercells.Theyfoundthattheaberrantdown-regulationofnucleostemininthesecellscausedadecreaseincellproliferation,suggestingthattheexpressionofnucleosteminisrequiredforstemcell--andsomecancercell--proliferation.
8 k4 p- l' W+ L0 ~1 sAlthoughtheprecisemechanismofnucleosteminactionisnotyetfullyunderstood,theidentificationofagenewhoseproteinproductspecificallypromotestheproliferationofstemcellsandsomecancercellshasimportantclinicalimplicationsforboththeuseofstemcellsinregenerativemedicineaswellasthetreatmentofcancer.AsDr.Tsaiexplains,Thecharacterizationofnucleosteminsuggeststhatauniqueprimitivestateissharedbybothstemcellsandcancercelllines.Theidentificationofcommonmoleculessharedbybothstemcellsandcancercellsmayfacilitatethediscoveryofself-renewingpopulationswithinagiventumorbyevaluatingtheirexpressionlevels.Perhaps,inthefuture,targetingthesecellswillachieveabettertherapeuticoutcome.% O+ x. k6 z  q. y+ \

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来源: Cold Spring Harbor Laboratory* S( j5 }) c1 ^+ V
发布者: 刘斌