Mechanochemical regulation of oscillatory follicle cell dynamics in the developing Drosophila egg chamber.
Mechanochemical regulation of oscillatory follicle cell dynamics in the developing Drosophila egg chamber.
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DOI：
10.1091/mbc.e14-04-0875
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发表时间：
2014-11-05
影响因子：
3.3
通讯作者：
Sun SX
中科院分区：
文献类型：
--
作者：
Koride S;He L;Xiong LP;Lan G;Montell DJ;Sun SX
在果蝇的上皮中，在组织伸长过程中，滤泡细胞的收缩力可能会振荡。这些振荡与卵室生长导致的上皮张力增加相关。提出了一个数学模型来解释观察到的振荡，以及细胞收缩力主动调节的机制。在果蝇卵子发生过程中，从第 9 阶段到第 10 阶段的组织伸长期间，卵室长度增加约 1.7 倍，而体积增加 8 倍。在这些阶段中，一部分滤泡细胞会出现细胞基底表面收缩的自发振荡。这种模式化的活动是卵室伸长所必需的；然而，产生时空模式的机制尚不清楚。在这里，我们结合定量模型和实验扰动来证明机械化学相互作用足以在观察到的时空模式中产生肌球蛋白收缩活动的振荡。我们认为上皮层中的卵泡细胞抵抗不断扩大的卵室中的压力而收缩。随着上皮层张力的增加，Rho 激酶信号传导激活肌球蛋白组装和收缩。激活过程是协作的，导致肌球蛋白动力学的极限循环。我们的模型在卵泡细胞面积和肌球蛋白含量中产生异步振荡，与实验观察结果一致。此外，我们还测试了去除基底层将增加平均振荡周期的预测。该模型表明，原则上，机械化学相互作用足以驱动图案化和形态发生，而与图案化基因表达无关。
In the epithelium of Drosophila during tissue elongation, contractile forces in follicle cells can oscillate. These oscillations correlate with increasing tension in the epithelium from egg chamber growth. A mathematical model is proposed to explain the observed oscillations, together with a mechanism of active regulation of cellular contractile forces. During tissue elongation from stage 9 to stage 10 in Drosophila oogenesis, the egg chamber increases in length by ∼1.7-fold while increasing in volume by eightfold. During these stages, spontaneous oscillations in the contraction of cell basal surfaces develop in a subset of follicle cells. This patterned activity is required for elongation of the egg chamber; however, the mechanisms generating the spatiotemporal pattern have been unclear. Here we use a combination of quantitative modeling and experimental perturbation to show that mechanochemical interactions are sufficient to generate oscillations of myosin contractile activity in the observed spatiotemporal pattern. We propose that follicle cells in the epithelial layer contract against pressure in the expanding egg chamber. As tension in the epithelial layer increases, Rho kinase signaling activates myosin assembly and contraction. The activation process is cooperative, leading to a limit cycle in the myosin dynamics. Our model produces asynchronous oscillations in follicle cell area and myosin content, consistent with experimental observations. In addition, we test the prediction that removal of the basal lamina will increase the average oscillation period. The model demonstrates that in principle, mechanochemical interactions are sufficient to drive patterning and morphogenesis, independent of patterned gene expression.