Mesodermal patterning activity of SCL
Mesodermal patterning activity of SCL
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DOI：
10.1016/j.exphem.2008.07.005
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发表时间：
2008-12-01
影响因子：
2.6
通讯作者：
Kyba, Michael
中科院分区：
文献类型：
--
作者：
Ismailoglu, Ismail;Yeamans, Gabriel;Kyba, Michael
转录因子 SCL 对于建立造血作用和正常的内皮发育至关重要，但对于维持成人的造血干细胞或内皮细胞不是必需的。关于 SCL 的发育功能，存在相互矛盾的数据，即它是否充当主调节者，以牺牲其他谱系为代价积极地使中胚层走向造血发育，还是仅仅需要维持最早的造血前体细胞。为了回答这个问题，我们用条件性多西环素诱导的 SCL 转基因改造了小鼠胚胎干细胞，并评估了体外发育过程中特定时间点 SCL 表达的影响。分化过程中持续的 SCL 表达导致造血作用显着增加。通过使用 6 天分化时间过程中的基因表达脉冲，我们绘制并表征了 SCL 反应性窗口。值得注意的是，早期中胚层模式（分化48至72小时）期间SCL表达的脉冲促进了Flk1（+）PDGFRα（阴性）假定的胚外/侧板中胚层，但牺牲了PDGFRα（+）Flk1（阴性）假定的轴旁中胚层。与此一致的是，SCL表达的早期脉冲也增加了造血集落形成细胞的数量，同时抑制轴旁和心脏标志物的表达，并抑制跳动心肌细胞的发育。通过将诱导型胚胎干细胞与嵌合胚状体中荧光标记的野生型细胞混合，我们证明 SCL 的这些作用是细胞自主的。这些数据支持 SCL 在中胚层模式形成中的主要调节作用，以及其后来在造血分化中的作用。 (C) 2008 ISEH - 血液学和干细胞学会。由爱思唯尔公司出版
The transcription factor SCL is critically required for establishing hematopoiesis and for proper endothelial development, but not for maintenance of hematopoietic stem cells or endothelial cells in the adult. Conflicting data exists regarding the developmental function of SCL, namely, whether it acts as a master regulator, actively patterning mesoderm toward hematopoietic development at the expense of other lineages, or is merely necessary to maintain the earliest committed hematopoietic precursors. To answer this question, we have engineered murine embryonic stem cells with a conditional doxycycline-inducible SCL transgene, and evaluated the effects of SCL expression at defined time points during in vitro development. Continual SCL expression during differentiation results in markedly increased hematopoiesis. By using pulses of gene expression over a 6-day differentiation time course, we map and characterize windows of SCL responsiveness. Notably, a pulse of SCL expression during early mesodermal patterning (48 to 72 hours of differentiation) promoted Flk1(+) PDGFR alpha(neg) presumptive extraembryonic/lateral plate mesoderm at the expense of PDGFR alpha(+) Flk1(neg) presumptive paraxial mesoderm. Consistent with this, the early pulse of SCL expression also expanded hematopoietic colony-forming cell numbers, while concomitantly repressing expression of paraxial and cardiac markers, and inhibited development of beating cardiomyocytes. By mixing the inducible embryonic stem cells with fluorescently labeled wild-type cells in chimeric embryoid bodies, we show that these effects of SCL are cell autonomous. These data support a master-regulatory role for SCL in mesodermal patterning, in addition to its established later roles in hematopoietic differentiation. (C) 2008 ISEH - Society for Hematology and Stem Cells. Published by Elsevier Inc.