Dose-dependent nuclear β-catenin response segregates endomesoderm along the sea star primary axis
Dose-dependent nuclear β-catenin response segregates endomesoderm along the sea star primary axis
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DOI：
10.1242/dev.113043
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发表时间：
2015-01-01
期刊：
影响因子：
4.6
通讯作者：
Hinman, Veronica F.
中科院分区：
文献类型：
--
作者：
McCauley, Brenna S.;Akyar, Eda;Hinman, Veronica F.
在许多无脊椎动物中，β-连环蛋白在胚胎的一极的核化启动内中胚层特化。一个有趣的可能性是，核β-连环蛋白（n β-连环蛋白）的梯度，类似于脊椎动物神经管模式中的操作，用于区分无脊椎动物中的细胞命运。为了验证这一假设，我们确定了n β-连环蛋白的功能，在早期发展的海星星，它经历了一个基础的后口模式的胚胎发生。我们发现，低水平的n β-连环蛋白活性启动bra，这是在未来的后内胚层命运的领土表达;中间水平所需的表达foxa和gata 4/5/6，这是后来限制到内胚层;和激活ets 1和erg在中胚层命运的领土需要最高的n β-连环蛋白活性。作用于高n β-连环蛋白下游的转录因子分离内胚层/中胚层边界，这通过Delta/Notch信号传导进一步加强。值得注意的是，因此，在海星，内中胚层分离通过转录反应水平的n β-连环蛋白活性。在这里，我们描述了第一个经验证据的剂量依赖性反应的动态时空n β-连环蛋白的活动，图案细胞命运沿着主轴在无脊椎动物。
In many invertebrates, the nuclearization of beta-catenin at one pole of the embryo initiates endomesoderm specification. An intriguing possibility is that a gradient of nuclear beta-catenin (n beta-catenin), similar to that operating in vertebrate neural tube patterning, functions to distinguish cell fates in invertebrates. To test this hypothesis, we determined the function of n beta-catenin during the early development of the sea star, which undergoes a basal deuterostomal mode of embryogenesis. We show that low levels of n beta-catenin activity initiate bra, which is expressed in the future posterior endoderm-fated territory; intermediate levels are required for expression of foxa and gata4/5/6, which are later restricted to the endoderm; and activation of ets1 and erg in the mesoderm-fated territory requires the highest n beta-catenin activity. Transcription factors acting downstream of high n beta-catenin segregate the endoderm/mesoderm boundary, which is further reinforced by Delta/Notch signaling. Significantly, therefore, in sea stars, endomesoderm segregation arises through transcriptional responses to levels of n beta-catenin activity. Here, we describe the first empirical evidence of a dose-dependent response to a dynamic spatiotemporal n beta-catenin activity that patterns cell fates along the primary axis in an invertebrate.