Frog eggs rejuvenate human cells

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日期: 2003-07-16 今日/总浏览: 1/5796 D' y  K- |) H+ J8 V! F* V

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6 I$ s/ p1 o! Z+ `  cImmaturefrogeggscanrejuvenateadulthumancells.MoleculesintheamphibiannucleuscoaxmaturehumanandmouseDNAbacktoanadaptable,stem-cell-likestate1.$ {( J( w  _/ r9 ?: s5 d9 p
JohnGurdonandhiscolleaguesatCambridgeUniversity,UK,hopetoisolatethesubstancesresponsibleandusethemtoreprogrammeordinaryadultcells,fromskinorblood,say.Thiswouldyieldalimitlesssupplyofdonor-matchedstemcellswithwhichtorepairtissuedamagedindiseasessuchasParkinson'sandmultiplesclerosis.
; q7 O5 Q3 n8 l& W) ~Manyresearchersarehopingtoconvertspecializedadultcellsintoamoreimmaturestate.Stemcellscanbederivedfromexcessearly-stagehumanembryosfromfertilitytreatments.Butthisapproachhasethicalandpracticallimitations-theEuropeanUnionlastweekruledthatonlyembryoscreatedbefore27June2002canbeusedforresearch.Adultstemcellsexist,buttheirpotentialisuncertain.
0 }: P$ Y* U- e' OGurdon'steaminjectedimmatureXenopusfrogeggswithnucleifromadultmouseorhumanwhitebloodcells.Twodayslater,thedefinitivemouseorhumanstem-cellmarker,amoleculecalledOct4RNA,appearedinthehybrid.RNAhelpstoconvertDNAtoproteins,sotheresulthintsthattheadultnucleiarestartingtobehaveinastem-cell-likeway.- G9 X0 n1 w- ]7 H7 y
Thisisthefirststepinreprogrammingcells,agreesdevelopmentalgeneticistWolfReikoftheBabrahamInstituteinCambridge,UK,beforeadding:Youmightstillrunintoproblemslateron.Somegenesmayremainintheiradultform,causingcellstodivideandbecomecancerous.8 S# k! A; ^. P5 H* o( O( l; b
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Nuclearreaction
7 \, M6 n& G. Y1 l0 }( _: uThetechniqueisdifferentfromtheprocessusedtocreateDollythesheep.TomakeDolly,researchersinjectedadultDNAintoanemptysheepeggandstimulatedittodevelop.Gurdon'sapproachleavestheegg'snucleusinplace.: A: v8 N* q3 u4 @0 z8 X8 Z
Whentheresearchersinjectedtheadultnucleiintofrogeggnucleii,ratherthanintothesurroundingcytoplasm,Oct4levelsshotupbyafactoroften.Thereprogrammingactivityisparticularlyconcentratedhere,saysGurdon.Moleculesinthefrognucleusmayberesponsiblefortheeggs'revitalizingabilities,hespeculates.1 N, r" r  z8 @, X  [  @  ^6 S
Frogeggsarelargeandeasytomanipulate,sayscellbiologistRudolfJaenischoftheWhiteheadInstituteinCambridge,Massachusetts.Theygiveyouausefultoolforfindingthegenesthatareinvolvedinreprogramming,hesays.( F3 l# L5 Q: F

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References
$ B) f1 Q3 ]# N8 u* N* C8 CByrne,J.A.,Simonsson,S.,Western,P.S.&Gurdon,J.B.Nucleiofadultmammaliansomaticcellsaredirectlyreprogrammedtooct-4stemcellsgeneexpressionbyamphibianoocytes.CurrentBiology,13,1206-1213,(2003).0 n$ @% }: v& L+ u8 z) y2 [
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2 c0 @$ Y" |; ~$ q作者: HELEN R. PILCHER/ E: P/ ]: n( `* Q2 ?4 }$ Y
来源: Nature
! B; x% x& X, q& |发布者: 亦云