New stem cell maintenance protein found

韩雪娜

日期: 2002-12-02 今日/总浏览: 1/696' |9 D' ]! h/ O( K
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- {% D% ]8 n& l6 {1 {2 PRonald D.G. McKay, Ph.D.
7 f$ J$ {, y) ^6 r6 F5 mScientistshaveidentifiedacritical,newstemcellprotein?amarkedadvanceintheelucidationofthemolecularblueprintofstemcells.
) i/ ^4 r7 B, w  D' U" l9 S5 EDrs.RobertTsaiandRonaldMcKayattheNIHhavediscoveredanovelgene,callednucleostemin,whoseencodedproteinisnecessaryformaintainingtheproliferativecapacityofembryonicandadultstemcells,andpossiblysometypesofcancercells.TheirreportispublishedintheDecember1issueofthescientificjournalGenes&Development.  _; Q+ R+ j& d7 Y0 Q# y
Embryonicstemcellsarepluripotentprogenitorcellsthatcandifferentiateintoallofthecelltypesofthebody.Adultstemcells,incontrast,havealessversatilepotential:Theirdifferentiationisgenerallyrestrictedtothecelltypesofaspecifictissue(althoughrecentworkhasexpandedthepreviouslyknownrangeofadultstemcelldifferentiationpotential).7 G! e9 `! J2 U# d/ y( T  ~
Akeyfeatureofbothembryonicandadultstemcellsistheircapacityforself-renewalaswellasdifferentiation?ensuringthataconstantpoolofundifferentiatedstemcellsalwaysexists.Drs.TsaiandMcKayhaveidentifiednucleosteminasacriticalregulatorofthisdelicatebalance.
3 q6 a! g+ i( P4 r1 B$ M+ n* KDrs.TsaiandMcKayoriginallyidentifiednucleosteminasaproteinabundantlyexpressedinratCNS(centralnervoussystem)stemcellsthatismarkedlydown-regulatedduringdifferentiation,suggestingapossibleroleinstemcellmaintenance.Theresearcherswentontoshowthatnucleosteminisexpressedinvariousadultandembryonicstemcellpopulations,aswellasinsomehumancancercelllines,andthatitsexpressionisconsistentlyturned-offduringthedifferentiationofstemcellsintomorespecializedcelltypes.
' I1 m  l' \' u5 _, t7 f! c1 R$ tUsingtheRNAigenesilencingmethod,Drs.TsaiandMcKaydisruptednormalnucleosteminexpressionpatternsinrodentCNSstemcellsandhumanosteosarcomacancercells.Theyfoundthattheaberrantdown-regulationofnucleostemininthesecellscausedadecreaseincellproliferation,suggestingthattheexpressionofnucleosteminisrequiredforstemcell--andsomecancercell--proliferation.
4 q  j* N& c6 c6 PAlthoughtheprecisemechanismofnucleosteminactionisnotyetfullyunderstood,theidentificationofagenewhoseproteinproductspecificallypromotestheproliferationofstemcellsandsomecancercellshasimportantclinicalimplicationsforboththeuseofstemcellsinregenerativemedicineaswellasthetreatmentofcancer.AsDr.Tsaiexplains,Thecharacterizationofnucleosteminsuggeststhatauniqueprimitivestateissharedbybothstemcellsandcancercelllines.Theidentificationofcommonmoleculessharedbybothstemcellsandcancercellsmayfacilitatethediscoveryofself-renewingpopulationswithinagiventumorbyevaluatingtheirexpressionlevels.Perhaps,inthefuture,targetingthesecellswillachieveabettertherapeuticoutcome.
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作者: : a% h- G/ `! F0 S0 b4 ^
来源: Cold Spring Harbor Laboratory
: ?, E8 E5 e7 S发布者: 刘斌