達(dá)能促進(jìn)胚外內(nèi)胚層,，而SOX17則誘導(dǎo)定型內(nèi)胚層,。）
胚胎干細(xì)胞是一種具有獨(dú)特生物學(xué)特性的細(xì)胞,，它能進(jìn)行自我更新,，并且能分化為內(nèi)胚層、中胚層和外胚層細(xì)胞,。因此,，了解胚胎干細(xì)胞和相關(guān)分化細(xì)胞的細(xì)胞命運(yùn)調(diào)控過(guò)程及影響因素，將幫助我們更好地研究胚胎發(fā)育,，并將有助于治療各種疾病,。
在2008年8月7日出版的《細(xì)胞—干細(xì)胞》（Cell Stem Cell）雜志上，來(lái)自加拿大的一組科學(xué)家發(fā)表了他們關(guān)于細(xì)胞命運(yùn)調(diào)控的最新研究結(jié)果,。研究小組通過(guò)派系決定（lineage-determining）轉(zhuǎn)錄因子的表達(dá)研究了內(nèi)胚層細(xì)胞的命運(yùn)調(diào)控,。結(jié)果證實(shí)，通過(guò)SOX7或者SOX17的組成性表達(dá)（constitutive expression）,，人類(lèi)胚胎干細(xì)胞能形成穩(wěn)定的內(nèi)胚層祖細(xì)胞,。組成性表達(dá)是一類(lèi)不大受到環(huán)境變動(dòng)而變化的基因表達(dá)，SOX7和SOX17的這種表達(dá)過(guò)程能分別產(chǎn)生胚外內(nèi)胚層和定型內(nèi)胚層祖細(xì)胞,。
研究中科學(xué)家們還發(fā)現(xiàn),，在畸胎瘤（teratoma）分析和生長(zhǎng)因子調(diào)節(jié)的分化過(guò)程中，SOX7似乎被局限于胚外內(nèi)胚層中,，而與此同時(shí),，SOX17細(xì)胞則在畸胎瘤中表現(xiàn)出一種中內(nèi)胚層顯性，并且顯示出在缺少細(xì)胞因子調(diào)節(jié)的內(nèi)胚層誘導(dǎo)情況下發(fā)生內(nèi)胚層成熟的能力,。
科學(xué)家最后表示,，新發(fā)現(xiàn)提供了一種研究?jī)?nèi)胚層分化過(guò)程的新工具。（生物谷Bioon.com）
生物谷推薦原始出處：
Cell Stem Cell,，Vol 3, 182-195, 07 August 2008,，Cheryle A. Séguin, Janet Rossant
Establishment of Endoderm Progenitors by SOX Transcription Factor Expression in Human Embryonic Stem Cells
Cheryle A. Séguin,1, Jonathan S. Draper,1,2,4 Andras Nagy,2,3 and Janet Rossant1,3,
1 The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G 1L7, Canada
2 Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
3 Department of Molecular Genetics, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
In this study, we explore endoderm cell fate regulation through the expression of lineage-determining transcription factors. We demonstrate that stable endoderm progenitors can be established from human ES cells by constitutive expression of SOX7 or SOX17, producing extraembryonic endoderm and definitive endoderm progenitors, respectively. In teratoma assays and growth factor-mediated differentiation, SOX7 cells appear restricted to the extraembryonic endoderm, and SOX17 cells demonstrate a mesendodermal phenotype in teratomas and the ability to undergo endoderm maturation in vitro in the absence of cytokine-mediated endoderm induction. These endoderm progenitor cells maintain a stable phenotype through many passages in culture, thereby providing new tools to explore the pathways of endoderm differentiation.
