Evidence for the temporal regulation of insect segmentation by a conserved sequence of transcription factors
Evidence for the temporal regulation of insect segmentation by a conserved sequence of transcription factors
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DOI：
10.1242/dev.155580
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发表时间：
2018-05-01
期刊：
影响因子：
4.6
通讯作者：
Peel, Andrew D.
中科院分区：
文献类型：
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作者：
Clark, Erik;Peel, Andrew D.
长胚芽的昆虫，如果蝇，同时形成它们的节，而短胚芽的昆虫，如三角甲虫，从前到后依次形成它们的节。虽然这两种分割模式一开始看起来非常不同，但这种差异可能只是反映了发育的异质性。我们现在在这里表明，在果蝇和Tribolium中，片段模式发生在一个顺序的尾端，双端和奇对表达的共同框架内。在果蝇中，这些转录因子像简单的计时器一样在胚皮中表达，而在Tribolium中，它们形成从前到后横扫胚带的波阵面。在果蝇中，已知这三种基因都调节成对规则基因的表达并影响片段的时间进展。我们认为这些调控作用在短胚中是保守的，因此这些基因在昆虫中表达谱的变化为观察到的片段时间差异提供了机制解释。为了支持这一假设，我们证明奇数对Tribolium的分割是必不可少的，与以前的报道相反。
Long-germ insects, such as the fruit fly Drosophila melanogaster, pattern their segments simultaneously, whereas short-germ insects, such as the beetle Tribolium castaneum, pattern their segments sequentially, from anterior to posterior. Although the two modes of segmentation at first appear quite distinct, much of this difference might simply reflect developmental heterochrony. We now show here that, in both Drosophila and Tribolium, segment patterning occurs within a common framework of sequential Caudal, Dichaete and Odd-paired expression. In Drosophila, these transcription factors are expressed like simple timers within the blastoderm, whereas in Tribolium they form wavefronts that sweep from anterior to posterior across the germband. In Drosophila, all three are known to regulate pair-rule gene expression and influence the temporal progression of segmentation. We propose that these regulatory roles are conserved in short-germ embryos, and that therefore the changing expression profiles of these genes across insects provide a mechanistic explanation for observed differences in the timing of segmentation. In support of this hypothesis, we demonstrate that Odd-paired is essential for segmentation in Tribolium, contrary to previous reports.