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英国剑桥大学21日发表新闻公报说，该校研究人员确认一种名为“Nanog”的蛋白质是干细胞具有发育成各种类型细胞能力的“总开关”。无论是在胚胎干细胞还是诱导多功能干细胞中，它都起着关键作用。
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% u- M C! D; K K. L5 ^/ W- l人类胚胎细胞具有神奇的全能性，可以随着胚胎成长而发育成人体不同器官的细胞，如骨骼、皮肤、内脏、神经等各种细胞。近年来，科学家又发现可通过基因改造使普通皮肤细胞等具有与胚胎干细胞类似的全能性，称为诱导多功能干细胞。但是，科学界一直不清楚这两种细胞具有全能性的深层机理。
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剑桥大学的新闻公报说，该校研究人员发现“Nanog”蛋白质在细胞获得全能性的一系列复杂过程中发挥着非常关键的作用。如果没有它，胚胎干细胞将不会发育，而诱导产生多功能干细胞的过程也会失败。! h1 e% K0 E- E' d0 x X
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研究人员解释说，“Nanog”并不是单独起作用，它更像一个“乐队指挥”，协调着一系列基因和蛋白质，让它们在各自正确的位置上发挥作用，最终为细胞带来神奇的全能性。研究人员将进一步研究这种蛋白质是如何“发号施令”的。( A& p% k: [+ t( t V
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相关研究报告发表在新一期美国《细胞》杂志上。（生物谷Bioon.com）: L2 p3 ]1 U* \4 A/ n- `
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原始出处：* I. {. L% [. A. `
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Cell, Volume 138, Issue 4, 722-737, 21 August 2009 doi:10.1016/j.cell.2009.07.039
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Nanog Is the Gateway to the Pluripotent Ground State
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Jose Silva1,2,6,,,Jennifer Nichols1,3,6,Thorold W. Theunissen1,2,Ge Guo1,2,Anouk L. van Oosten1,2,Ornella Barrandon1,2,Jason Wray1,2,Shinya Yamanaka4,Ian Chambers5andAustin Smith1,2,,2 B8 x9 f) v* _/ l% \
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1 Wellcome Trust Centre for Stem Cell Research, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK
2 O2 T5 J* d% E. i2 Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK" A4 c0 B0 k. ^
3 Department of Physiology, Development, and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QR, UK- R& C( P k% H7 f* Z* A
4 Department of Stem Cell Biology, Institute for Frontier Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
/ K: R Q5 K5 N( s7 a/ `5 MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JQ, UK. ]9 w; L/ Z+ P7 u6 o+ k3 {" F5 b
& y O4 _0 |/ L* ~Pluripotency is generated naturally during mammalian development through formation of the epiblast, founder tissue of the embryo proper. Pluripotency can be recreated by somatic cell reprogramming. Here we present evidence that the homeodomain protein Nanog mediates acquisition of both embryonic and induced pluripotency. Production of pluripotent hybrids by cell fusion is promoted by and dependent on Nanog. In transcription factor-induced molecular reprogramming, Nanog is initially dispensable but becomes essential for dedifferentiated intermediates to transit to ground state pluripotency. In the embryo, Nanog specifically demarcates the nascent epiblast, coincident with the domain of X chromosome reprogramming. Without Nanog, pluripotency does not develop, and the inner cell mass is trapped in a pre-pluripotent, indeterminate state that is ultimately nonviable. These findings suggest that Nanog choreographs synthesis of the naive epiblast ground state in the embryo and that this function is recapitulated in the culmination of somatic cell reprogramming. |
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发表于 2010-6-3 11:23
发表于 2010-7-30 14:45
