Gata is ubiquitously required for the earliest zygotic gene transcription in the ascidian embryo
Gata is ubiquitously required for the earliest zygotic gene transcription in the ascidian embryo
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DOI：
10.1016/j.ydbio.2019.11.009
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发表时间：
2020-02-15
影响因子：
2.7
通讯作者：
Satou, Yutaka
中科院分区：
文献类型：
--
作者：
Imai, Kaoru S.;Kobayashi, Kenji;Satou, Yutaka
在海鞘胚胎中，合子基因组的最早转录开始于8细胞和16细胞阶段之间。Gata.a是一种母系表达的加塔转录因子，特异性地激活动物半球中的靶基因，而β-连环蛋白和Tcf 7的复合物拮抗Gata.a的活性并特异性地激活植物半球中的靶基因。在这里，我们表明，在16细胞阶段合子表达的基因有显着更多的加塔基序在其上游地区。这些基因不仅包括动物半球特异性表达的基因，也包括植物半球特异性表达的基因。基于这一发现，我们进行了Gata. a和报告基因测定的敲除实验，发现Gata. a不仅是动物半球特异性表达基因的表达所需的，也是植物半球特异性表达基因的表达所需的。我们的数据表明，弱Gata. a活性，不能诱导动物半球特异性表达，可以允许β-连环蛋白/Tcf 7目标在植物细胞中表达。由于在32细胞期合子表达的基因在其上游区域也具有显著更多的加塔基序，因此Gata. a功能可能不限于在16细胞期动物或植物半球中特异性表达的基因，并且Gata. a可能在合子基因组的最早转录中起重要作用。
In ascidian embryos, the earliest transcription from the zygotic genome begins between the 8-cell and 16-cell stages. Gata.a, a maternally expressed Gata transcription factor, activates target genes specifically in the animal hemisphere, whereas the complex of beta-catenin and Tcf7 antagonizes the activity of Gata.a and activates target genes specifically in the vegetal hemisphere. Here, we show that genes zygotically expressed at the 16-cell stage have significantly more Gata motifs in their upstream regions. These genes included not only genes with animal hemisphere-specific expression but also genes with vegetal hemisphere-specific expression. On the basis of this finding, we performed knockdown experiments for Gata.a and reporter assays, and found that Gata.a is required for the expression of not only genes with animal hemisphere-specific expression, but also genes with vegetal hemisphere-specific expression. Our data indicated that weak Gata.a activity that cannot induce animal hemisphere-specific expression can allow beta-catenin/Tcf7 targets to be expressed in the vegetal cells. Because genes zygotically expressed at the 32-cell stage also had significantly more Gata motifs in their upstream regions, Gata.a function may not be limited to the genes expressed specifically in the animal or vegetal hemispheres at the 16-cell stage, and Gata.a may play an important role in the earliest transcription of the zygotic genome.