Shisa2 promotes the maturation of somitic precursors and transition to the segmental fate in Xenopus embryos
Shisa2 promotes the maturation of somitic precursors and transition to the segmental fate in Xenopus embryos
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DOI：
10.1242/dev.02657
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发表时间：
2006-12-01
期刊：
影响因子：
4.6
通讯作者：
Yamamoto, Akihito
中科院分区：
文献类型：
--
作者：
Nagano, Takashi;Takehara, Shoko;Yamamoto, Akihito
在脊椎动物体细胞发生中，FGF 和 Wnt 信号构成形态发生梯度，控制前体中胚层 (PSM) 的成熟以及向节段单位的过渡。然而，目前尚不清楚是否存在通过直接调节 PSM 中的 FGF 和 Wnt 信号传导来促进转变的调节机制。在这里，我们表明 Shisa2 是一个新的 Shisa 基因家族的成员，在非洲爪蟾体节发生过程中的节段模式中发挥着重要作用。 Shisa2 编码一种内质网 (ER) 蛋白，该蛋白通过阻止 FGF 和 Wnt 受体的成熟和细胞表面表达来细胞自主抑制 FGF 和 Wnt 信号传导。 Shisa2 在 PSM 中表达，其敲低通过 PSM 成熟延迟和过渡前移导致体节数量减少；然而，分段时钟的相位保持不变。这些表型可以通过抑制 FGF 和 Wnt 信号而消除，但不能单独抑制。因此，我们认为通过调节内质网受体成熟来单独抑制两种类型的信号传导在建立适当的节段模式中起着至关重要的作用。
In vertebrate somitogenesis, FGF and Wnt signals constitute a morphogenetic gradient that controls the maturation of the presomitic mesoderm (PSM) as well as the transition to segmental units. It remains unclear, however, whether there is a regulatory mechanism that promotes the transition by a direct regulation of FGF and Wnt signaling in the PSM. Here we show that Shisa2, a member of a novel Shisa gene family, plays an essential role in segmental patterning during Xenopus somitogenesis. Shisa2 encodes an endoplasmic reticulum ( ER) protein that cell-autonomously inhibits FGF and Wnt signaling by preventing the maturation and the cell-surface expression of their receptors. Shisa2 is expressed in the PSM and its knockdown caused a reduction in somite number by the delayed maturation of PSM and anterior shift of the transition; however, the phase of the segmental clock remained intact. These phenotypes were abolished by the inhibition of both FGF and Wnt signals, but by neither alone. We therefore propose that the individual inhibition of both types of signaling by the regulation of receptor maturation in the ER plays an essential role in the establishment of proper segmental patterning.