Stem Cell Self-Renewal Gene Identified

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日期: 2003-11-02 今日/总浏览: 1/416/ ?7 p9 V  ]) `6 v7 s2 r& F6 V
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2 B3 v1 U  ]* n) _4 N* T( U0 \Brain stem cells from mice that contain the Bmi-1 gene (top) proliferate more readily than those without the gene (bottom).$ w. }5 W' r" M4 D$ Q5 e8 D1 r" N
Oneofthemostperplexingquestionsinstemcellbiologyis“Whatmakesastemcellastemcell?”Researchersstudyingadultstemcellswouldliketoknowwhatdistinguishesastemcell,whichcanreplenishitselfindefinitely,fromaprogenitorcell,whichcanproliferateonlyalimitednumberoftimes.Now,researchersareonestepclosertounderstandingthedifference.
7 k! P. o/ t. A3 C& ^0 I3 A* A: sResearchersattheUniversityofMichiganinAnnArborhaveidentifiedagenethatisrequiredfortheproliferationofthreetypesofadultstemcellsfrommice.Stemcellsfromthecentralnervoussystem,theperipheralnervoussystemandthebloodallrelyonagenecalledBmi-1torenewthemselves.However,thegeneisnotrequiredfortheproliferationofprogenitorcellsfromthesametissues.
9 s+ K3 N. U/ h; @  r7 W6 F+ i7 H; v“Thisisthefirstgeneidentifiedthatisconsistentlyrequiredbystemcellstoproliferate,butit'snotrequiredbyatleastsometypesofprogenitorcells,”saysSeanJ.Morrison,wholedtheresearch.“Weexpectedthattherewouldbegeneslikethis,butitwasreallyexcitingtofinallyfindone.”
: ~! E- \. [  T1 E3 y* U: SResearcherswouldliketoidentifythegenesthatdistinguishstemcellsfromprogenitorcellsbecausethetwoareoftenconfused.Stemcellsaremoredifficulttoisolatebecausetherearefarfeweroftheminthebody,buttheyareconsideredmoreusefulbecausetheyproliferateincultureandcanreplacemostofthecelltypesofagiventissue.: Z  O9 D. X  z4 H
PreviousstudiesbyMorrisonandMichigancolleagueMichaelF.ClarkeshowedthattheBmi-1geneisneededtomaintainstemcellsfromtheblood.Thenewstudy,reportedinNature,showsthatthegeneisalsorequiredbynervestemcellsfromthebrainandgut.Thenewstudyfurthershowsthatthegeneaffectstheprocessofproliferation,buthasnoeffectonhowlongacellsurvives.
  T- f$ P1 j5 j, Z* h9 t1 XMaartenvanLohuizenoftheNetherlandsCancerCenterinAmsterdamdiscoveredtheBmi-1geneincancercellsin1991andfoundthatitblockstwoproteinsthatnormallyinhibitcellproliferation.
# z; m& R/ |2 y/ H; YVanLohuizenalsofindsthatthegeneisneededfortherenewalofstemcells.Hisstudiesalsosuggestthatthegeneisactiveinsomecellsinthecerebellumthatdonotappeartobestemcells.1 h" o4 P8 Z6 H2 B
Interestingly,manycancercellsalsooverexpressthegene.Becausethegenemakescellsimmortal,itmayplayakeyroleincancerdevelopment.ResearchersstudyingbothcancerandstemcellsarekeenonfiguringoutwhichgenesareregulatedbyBmi-1.
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作者: Nancy Touchette/ w- b* k6 @0 H9 t6 F% ?/ ?
来源: Genome News Network
, K$ \3 B- ?! [2 x发布者: 亦云