Conserved roles for Oct4 homologues in maintaining multipotency during early vertebrate development
Conserved roles for Oct4 homologues in maintaining multipotency during early vertebrate development
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DOI：
10.1242/dev.02362
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发表时间：
2006-05-15
期刊：
影响因子：
4.6
通讯作者：
Brickman, JM
中科院分区：
文献类型：
--
作者：
Morrison, GM;Brickman, JM
所有脊椎动物胚胎在原肠胚形成前都有多能细胞，但迄今为止，仅在小鼠和灵长类动物中获得了胚胎干细胞系。ES细胞来源于表达V类POU结构域（PouV）蛋白Oct4的哺乳动物内细胞团（ICM）组织。在小鼠中，Oct4的缺失导致不能维持ICM，因此不能衍生ES细胞。在这里，我们表明，Oct4同源物也在早期两栖动物的发展，他们作为抑制剂的承诺在胚层规格。爪蟾胚胎中的反义吗啉代介导的PouV敲除导致严重的后部截短和前部神经缺陷。原肠胚阶段胚胎显示与未定型边缘区细胞相关的基因表达减少，而与更成熟细胞状态相关的标记物表达增加。重要的是，我们已经测试了来自许多脊椎动物物种的PouV蛋白在小鼠ES细胞中替代Oct4的能力。来自非洲爪蟾和美西蝾螈的PouV结构域蛋白可以支持小鼠ES细胞自我更新，但在这个家族中唯一鉴定的斑马鱼蛋白不能。此外，我们发现PouV蛋白在ES细胞和非洲爪蟾胚胎中调节相似的基因，并且能够支持ES细胞自我更新的PouV蛋白也可以拯救非洲爪蟾PouV敲低表型。我们得出结论，Oct4维持ES细胞多能性的独特能力来自这类蛋白质维持多能性的祖先功能。
All vertebrate embryos have multipotent cells until gastrulation but, to date, derivation of embryonic stem (ES) cell lines has been achieved only for mouse and primates. ES cells are derived from mammalian inner cell mass (ICM) tissue that express the Class V POU domain (PouV) protein Oct4. Loss of Oct4 in mice results in a failure to maintain ICM and consequently an inability to derive ES cells. Here, we show that Oct4 homologues also function in early amphibian development where they act as suppressors of commitment during germ layer specification. Antisense morpholino mediated PouV knockdown in Xenopus embryos resulted in severe posterior truncations and anterior neural defects. Gastrulation stage embryos showed reduced expression of genes associated with uncommitted marginal zone cells, while the expression of markers associated with more mature cell states was expanded. Importantly, we have tested PouV proteins from a number of vertebrate species for the ability to substitute Oct4 in mouse ES cells. PouV domain proteins from both Xenopus and axolotl could support murine ES cell self-renewal but the only identified zebrafish protein in this family could not. Moreover, we found that PouV proteins regulated similar genes in ES cells and Xenopus embryos, and that PouV proteins capable of supporting ES cell self- renewal could also rescue the Xenopus PouV knockdown phenotype. We conclude that the unique ability of Oct4 to maintain ES cell pluripotency is derived from an ancestral function of this class of proteins to maintain multipotency.