Caudal Regulates the Spatiotemporal Dynamics of Pair-Rule Waves in Tribolium
Caudal Regulates the Spatiotemporal Dynamics of Pair-Rule Waves in Tribolium
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DOI：
10.1371/journal.pgen.1004677
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发表时间：
2014-10-01
期刊：
影响因子：
4.5
通讯作者：
Brown, Susan J.
中科院分区：
文献类型：
--
作者：
El-Sherif, Ezzat;Zhu, Xin;Brown, Susan J.
在短芽甲虫中，配对规则基因表达波从胚胎的后端向胚胎的前端传播，最终冻结成稳定的条纹，将前后轴分割成片段。脊椎动物中类似的波被认为是由于从后到前的频率梯度对分子时钟的调制而产生的。然而，到目前为止，无论是在脊椎动物还是在其他地方，都没有确定这种频率梯度的分子候选或功能作用。在这里，我们提供了证据，即TC-尾部表达的后梯度调节了Tribolium中配对规则基因表达的振荡频率。我们通过分析强敲除和轻度敲除尾部的TC-Even-Skip表达的时空动态，以及通过将尾部表达梯度的范围、水平和斜率与野生型以及不同的Tc-尾部调控因子的RNAi敲除的TC-Even-Skip表达的时空动态相关联来说明这一点。此外，我们还证明了频率梯度除了对胚芽胚层静态阶段的条纹产生具有绝对重要性外，还可能在胚胎层和脊椎动物的轴向伸长阶段作为对噪声的缓冲。我们的结果强调了频率梯度在图案形成中的作用。
In the short-germ beetle Tribolium castaneum, waves of pair-rule gene expression propagate from the posterior end of the embryo towards the anterior and eventually freeze into stable stripes, partitioning the anterior-posterior axis into segments. Similar waves in vertebrates are assumed to arise due to the modulation of a molecular clock by a posterior-to-anterior frequency gradient. However, neither a molecular candidate nor a functional role has been identified to date for such a frequency gradient, either in vertebrates or elsewhere. Here we provide evidence that the posterior gradient of Tc-caudal expression regulates the oscillation frequency of pair-rule gene expression in Tribolium. We show this by analyzing the spatiotemporal dynamics of Tc-even-skipped expression in strong and mild knockdown of Tc-caudal, and by correlating the extension, level and slope of the Tc-caudal expression gradient to the spatiotemporal dynamics of Tc-even-skipped expression in wild type as well as in different RNAi knockdowns of Tc-caudal regulators. Further, we show that besides its absolute importance for stripe generation in the static phase of the Tribolium blastoderm, a frequency gradient might serve as a buffer against noise during axis elongation phase in Tribolium as well as vertebrates. Our results highlight the role of frequency gradients in pattern formation.