The role of maternal activin-like signals in zebrafish embryos
The role of maternal activin-like signals in zebrafish embryos
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DOI：
10.1016/j.ydbio.2007.07.010
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发表时间：
2007-09-15
影响因子：
2.7
通讯作者：
Dougan, Scott T.
中科院分区：
文献类型：
--
作者：
Hagos, Engda G.;Fan, Xiang;Dougan, Scott T.
母系激活素样蛋白是转化生长因子-β超家族的一个亚类，在许多脊椎动物的体轴建立过程中发挥着关键作用，但它们在硬骨鱼中的作用尚不清楚。在斑马鱼中至少表达了两种母体激活素样蛋白，包括Vg1同源基因zDVR-1和结节相关基因Squint。我们对缺乏母体和合子斜视功能的胚胎的分析表明，在某些遗传背景下，母体斜视是形成背部和前部组织所必需的。在卵裂阶段，SB-505124处理有条件地使ALK4、5和7受体失活，排除了母体斜视、zDVR-1或其他激活素样配体在胚泡中期过渡之前的作用，当背轴建立时。此外，我们发现母体斜视和zDVR-1在卵裂阶段并不是诱导合子结节相关基因表达所必需的。当受体抑制持续到胚泡中期之后，结节相关基因的表达减少，导致中胚层和内胚层的进行性丧失。我们得出结论，在斑马鱼胚泡中期过渡之前，母体表达的激活素样信号并不起作用，但在轴形成的后期阶段确实具有可变的穿透作用。这与这些信号在非洲爪哇发育过程中的早期作用形成了鲜明对比。(C)2007 Elsevier Inc.保留所有权利。
Maternal Activin-like proteins, a subgroup of the TGF-beta superfamily, play a key role in establishing the body axes in many vertebrates, but their role in teleosts is unclear. At least two maternal Activin-like proteins are expressed in zebrafish, including the Vg1 orthologue, zDVR-1, and the nodal-related gene, Squint. Our analysis of embryos lacking both maternal and zygotic squint function revealed that maternal squint is required in some genetic backgrounds for the formation of dorsal and anterior tissues. Conditional inactivation of the ALK4, 5 and 7 receptors by SB-505 124 treatment during the cleavage stages ruled out a role for maternal Squint, zDVR-1, or other Activin-like ligands before the mid-blastula transition, when the dorsal axis is established. Furthermore, we show that maternal Squint and zDVR-1 are not required during the cleavage stages to induce zygotic nodal-related gene expression. nodal-related gene expression decreases when receptor inhibition continues past the mid-blastula transition, resulting in a progressive loss of mesoderm and endoderm. We conclude that maternally expressed Activin-like signals do not act before the mid-blastula transition in zebrafish, but do have a variably penetrant role in the later stages of axis formation. This contrasts with the early role for these signals during Xenopus development. (C) 2007 Elsevier Inc. All rights reserved.