Enhancer activities of amphioxus Brachyury genes in embryos of the ascidian, Ciona intestinalis
Enhancer activities of amphioxus Brachyury genes in embryos of the ascidian, Ciona intestinalis
复制标题
DOI：
10.1002/dvg.23240
复制
发表时间：
2018-08
期刊：
影响因子：
1.5
通讯作者：
Hitoshi Tominaga;N. Satoh;N. Ueno;Hiroki Takahashi
中科院分区：
文献类型：
--
作者：
Hitoshi Tominaga;N. Satoh;N. Ueno;Hiroki Takahashi
脊索和体节是独特的脊索动物结构。 T-box 转录因子基因 Brachyury 在脊索中表达，并在脊索的形成中发挥关键作用。在头索动物（Branchiostoma floridae）中，Brachyury 被复制为 BfBra1 和 BfBra2，它们也在体节形成区域表达。在一系列阐明脊索动物 Brachyury 表达调控机制的实验中，我们对尾索动物胚胎中的 BfBra 进行了 lacZ 报告基因分析。 Vista 分析表明，不仅在 5' 上游，而且在 3' 下游和 BfBra 的内含子中都存在保守的非编码序列。我们发现：（1）BfBra1和BfBra2的5'上游序列均促进肌肉细胞中lacZ的表达，（2）3'下游序列具有促进脊索细胞中lacZ表达的增强子活性，（3）BfBra2和BfBra1的内含子优先在肌肉和脊索细胞中表现出lacZ表达。这些结果表明共享的头索动物 Brachyury 增强机制也适用于尾索动物。我们讨论了与 Brachyury 表达在每个谱系特征的脊索动物特异性器官形成中的进化修饰相关的结果。
The notochord and somites are distinctive chordate structures. The T‐box transcription factor gene, Brachyury, is expressed in notochord and plays a pivotal role in its formation. In the cephalochordate, Branchiostoma floridae, Brachyury is duplicated into BfBra1 and BfBra2, which are expressed in the somite‐formation region as well. In a series of experiments to elucidate the regulatory machinery of chordate Brachyury expression, we carried out a lacZ reporter assay of BfBra in embryos of the urochordate, Ciona intestinalis. Vista analyses suggest the presence of conserved non‐coding sequences, not only in the 5′‐upstream, but also in the 3′‐downstream and in introns of BfBra. We found that: (1) 5′‐upstream sequences of both BfBra1 and BfBra2 promote lacZ expression in muscle cells, (2) 3′‐downstream sequences have enhancer activity that promotes lacZ expression in notochord cells, and (3) introns of BfBra2 and BfBra1 exhibit lacZ expression preferentially in muscle and notochord cells. These results suggest shared cephalochordate Brachyury enhancer machinery that also works in urochordates. We discuss the results in relation to evolutionary modification of Brachyury expression in formation of chordate‐specific organs characteristic of each lineage.