The Xenopus POU class V transcription factor XOct-25 inhibits ectodermal competence to respond to bone morphogenetic protein-mediated embryonic induction
The Xenopus POU class V transcription factor XOct-25 inhibits ectodermal competence to respond to bone morphogenetic protein-mediated embryonic induction
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DOI：
10.1016/j.mod.2007.09.005
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发表时间：
2007-11
影响因子：
2.6
通讯作者：
K. Takebayashi-Suzuki;Naoko Arita;Eri Murasaki;A. Suzuki
中科院分区：
文献类型：
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作者：
K. Takebayashi-Suzuki;Naoko Arita;Eri Murasaki;A. Suzuki
骨形态发生蛋白（BMPs）已被证明在控制外胚层细胞命运中发挥关键作用，通过在原肠形成过程中以神经组织为代价诱导表皮。在这里，我们提出证据表明爪蟾POU V类转录因子XOct-25通过抑制外胚层细胞在爪蟾胚胎发生过程中对BMP的反应能力来调节外胚层细胞的命运决定。当XOct-25在囊胚期后的外胚层过表达时，可抑制BMP受体激活下游外胚层细胞的早期BMP反应，促进神经诱导，同时抑制表皮分化。相反，抑制XOct-25在未来神经外胚层中的功能会导致表皮外胚层的扩张，而神经外胚层则会受损。抑制XOct-25功能导致的神经组织的减少可以通过减少内源性BMP信号来挽救，这表明XOct-25至少在一定程度上通过抑制BMP介导的表皮诱导（神经抑制）在神经组织的形成中起作用。这一假设得到了以下观察结果的支持：在以神经组织为代价诱导早期BMP靶基因和表皮方面，来自XOct-25突变体的外胚层细胞对BMP信号传导更为敏感，而过度表达XOct-25的细胞对BMP介导的诱导反应能力较弱。这些结果证明了XOct-25在外胚层中参与神经细胞或表皮细胞命运的重要作用，并强调了限制bmp介导的胚胎诱导反应能力的调节机制的重要性。
Bone morphogenetic proteins (BMPs) have been shown to play a key role in controlling ectodermal cell fates by inducing epidermis at the expense of neural tissue during gastrulation. Here, we present evidence that the Xenopus POU class V transcription factor XOct-25 regulates ectodermal cell fate decisions by inhibiting the competence of ectodermal cells to respond to BMP during Xenopus embryogenesis. When overexpressed in the ectoderm after the blastula stage, XOct-25 suppressed early BMP responses of ectodermal cells downstream of BMP receptor activation and promoted neural induction while suppressing epidermal differentiation. In contrast, inhibition of XOct-25 function in the prospective neuroectoderm resulted in expansion of epidermal ectoderm at the expense of neuroectoderm. The reduction of neural tissue by inhibition of XOct-25 function could be rescued by decreasing endogenous BMP signaling, suggesting that XOct-25 plays a role in the formation of neural tissue at least in part by inhibiting BMP-mediated epidermal induction (neural inhibition). This hypothesis is supported by the observation that ectodermal cells from XOct-25 morphants were more sensitive to BMP signaling than cells from controls in inducing both immediate early BMP target genes and epidermis at the expense of neural tissue, while cells overexpressing XOct-25 are less competent to respond to BMP-mediated induction. These results document an essential role for XOct-25 in commitment to neural or epidermal cell fates in the ectoderm and highlight the importance of a regulatory mechanism that limits competence to respond to BMP-mediated embryonic induction.