Differential temporal control of Foxa.a and Zic-r.b specifies brain versus notochord fate in the ascidian embryo
Differential temporal control of Foxa.a and Zic-r.b specifies brain versus notochord fate in the ascidian embryo
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DOI：
10.1242/dev.142174
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发表时间：
2017-01-01
期刊：
影响因子：
4.6
通讯作者：
Satou, Yutaka
中科院分区：
文献类型：
--
作者：
Ikeda, Tatsuro;Satou, Yutaka
在无脊椎脊索动物玻璃海鞘的胚胎中，两种转录因子Foxa. a和Zic-r.B是脑和脊索的特化所必需的，它们来自不同的细胞谱系。在脑谱系中，Foxa. a和Zic-r.B的表达没有时间重叠。在脊索谱系中，Foxa. a和Zic-r.B同时表达。在本研究中，我们发现Foxa. a和Zic-r.B在脑谱系中的时间非重叠表达受三种阻遏物调节：Prdm 1-r. a（以前称为BZ 1），Prdm 1-r.B（BZ 2）和Hes. a。在这三个阻遏基因的胚中，Foxa. a的表达在正常时间没有终止，而Zic-r.B的表达提前。因此，Foxa. a和Zic-r.B同时表达，这导致Brachyury及其下游通路的异位激活，用于脊索分化。因此，转录抑制子的时间控制对于Foxa. a和Zic-r. b对脑和脊索两种不同命运的规范是必不可少的。这种机制可能使有限的转录因子库在发育基因调控网络中重复使用。
In embryos of an invertebrate chordate, Ciona intestinalis, two transcription factors, Foxa.a and Zic-r.b, are required for specification of the brain and the notochord, which are derived from distinct cell lineages. In the brain lineage, Foxa.a and Zic-r.b are expressed with no temporal overlap. In the notochord lineage, Foxa.a and Zic-r.b are expressed simultaneously. In the present study, we found that the temporally non-overlapping expression of Foxa.a and Zic-r.b in the brain lineage was regulated by three repressors: Prdm1-r.a (formerly called BZ1), Prdm1-r.b (BZ2) and Hes.a. In morphant embryos of these three repressor genes, Foxa.a expression was not terminated at the normal time, and Zic-r.b was precociously expressed. Consequently, Foxa.a and Zic-r.b were expressed simultaneously, which led to ectopic activation of Brachyury and its downstream pathways for notochord differentiation. Thus, temporal controls by transcriptional repressors are essential for specification of the two distinct fates of brain and notochord by Foxa.a and Zic-r.b. Such a mechanism might enable the repeated use of a limited repertoire of transcription factors in developmental gene regulatory networks.