Determining the scale of the Bicoid morphogen gradient
Determining the scale of the Bicoid morphogen gradient
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DOI：
10.1073/pnas.0807655106
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发表时间：
2009-02-10
影响因子：
11.1
通讯作者：
Levine, Herbert
中科院分区：
文献类型：
--
作者：
Hecht, Inbal;Rappel, Wouter-Jan;Levine, Herbert
双子体是一种形态学，可在早期果蝇胚胎中建立前后轴。尽管双聚体轮廓的形式与简单的扩散/降解模型一致，但根据测得的扩散速率，观察到的长度尺度比应预期的要大得多。在这里，我们研究了两种可能影响这种梯度的可能机制，因此解决了这一分歧。首先，我们表明，包括在切割周期期间将核捕获和释放双核不会改变形态的长度尺度。更重要的是，由于细胞质流造成的对流运输可能会产生很大的作用。具体而言，我们基于（有限的）实验数据构建了一个简单的模型，并表明这种流程会导致与各种实验特征一致的双子型。具体而言，获得了观察到的长度尺度，建立了稳定的轮廓，并在不同长度的胚胎之间进行了改进的缩放。
Bicoid is a morphogen that sets up the anterior-posterior axis in early Drosophila embryos. Although the form of the Bicoid profile is consistent with a simple diffusion/degradation model, the observed length scale is much larger than should be expected based on the measured diffusion rate. Here, we study two possible mechanisms that could, in principle, affect this gradient and, hence, address this disagreement. First, we show that including trapping and release of Bicoid by the nuclei during cleavage cycles does not alter the morphogen length scale. More crucially, the inclusion of advective transport due to cytoplasmic streaming can have a large effect. Specifically, we build a simple model based on the (limited) experimental data and show that such a flow can lead to a Bicoid profile that is consistent with various experimental features. Specifically, the observed length scale is obtained, a steady profile is established, and improved scaling between embryos of different lengths is demonstrated.