Stem Cell Self-Renewal Gene Identified

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日期: 2003-11-02 今日/总浏览: 1/4160 v$ a- a; b7 b) }  N- [) k( g: t
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+ `& v- B7 |! ]+ a. N. k" L" SBrain stem cells from mice that contain the Bmi-1 gene (top) proliferate more readily than those without the gene (bottom).. z7 ^# j  s, o
Oneofthemostperplexingquestionsinstemcellbiologyis“Whatmakesastemcellastemcell?”Researchersstudyingadultstemcellswouldliketoknowwhatdistinguishesastemcell,whichcanreplenishitselfindefinitely,fromaprogenitorcell,whichcanproliferateonlyalimitednumberoftimes.Now,researchersareonestepclosertounderstandingthedifference.4 ^$ ]' Q4 k; _7 T) N9 B
ResearchersattheUniversityofMichiganinAnnArborhaveidentifiedagenethatisrequiredfortheproliferationofthreetypesofadultstemcellsfrommice.Stemcellsfromthecentralnervoussystem,theperipheralnervoussystemandthebloodallrelyonagenecalledBmi-1torenewthemselves.However,thegeneisnotrequiredfortheproliferationofprogenitorcellsfromthesametissues.
4 j/ C" }; X1 H“Thisisthefirstgeneidentifiedthatisconsistentlyrequiredbystemcellstoproliferate,butit'snotrequiredbyatleastsometypesofprogenitorcells,”saysSeanJ.Morrison,wholedtheresearch.“Weexpectedthattherewouldbegeneslikethis,butitwasreallyexcitingtofinallyfindone.”
, J6 F& ]; a1 U, r1 _; k$ UResearcherswouldliketoidentifythegenesthatdistinguishstemcellsfromprogenitorcellsbecausethetwoareoftenconfused.Stemcellsaremoredifficulttoisolatebecausetherearefarfeweroftheminthebody,buttheyareconsideredmoreusefulbecausetheyproliferateincultureandcanreplacemostofthecelltypesofagiventissue.
- k( l  t! f# m4 h( T, zPreviousstudiesbyMorrisonandMichigancolleagueMichaelF.ClarkeshowedthattheBmi-1geneisneededtomaintainstemcellsfromtheblood.Thenewstudy,reportedinNature,showsthatthegeneisalsorequiredbynervestemcellsfromthebrainandgut.Thenewstudyfurthershowsthatthegeneaffectstheprocessofproliferation,buthasnoeffectonhowlongacellsurvives.
1 \# \5 n8 J; VMaartenvanLohuizenoftheNetherlandsCancerCenterinAmsterdamdiscoveredtheBmi-1geneincancercellsin1991andfoundthatitblockstwoproteinsthatnormallyinhibitcellproliferation.
: A4 `* n  @# Y0 h  _: A- HVanLohuizenalsofindsthatthegeneisneededfortherenewalofstemcells.Hisstudiesalsosuggestthatthegeneisactiveinsomecellsinthecerebellumthatdonotappeartobestemcells.
1 F% {( O- j0 G! C' y% a* iInterestingly,manycancercellsalsooverexpressthegene.Becausethegenemakescellsimmortal,itmayplayakeyroleincancerdevelopment.ResearchersstudyingbothcancerandstemcellsarekeenonfiguringoutwhichgenesareregulatedbyBmi-1.$ R. A. g9 u. P1 U
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作者: Nancy Touchette2 T% n6 D$ {" Z
来源: Genome News Network
2 C1 Z) ~! T& }* v( T- c3 i4 w发布者: 亦云