A 'chemotactic dipole' mechanism for large-scale vortex motion during primitive streak formation in the chick embryo
A 'chemotactic dipole' mechanism for large-scale vortex motion during primitive streak formation in the chick embryo
复制标题
鸡胚原条形成过程中大规模涡旋运动的“趋化偶极子”机制
DOI：
10.1088/1478-3975/8/4/045008
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发表时间：
2011
期刊：
影响因子：
2
通讯作者：
Sandersius S
中科院分区：
文献类型：
--
作者：
Sandersius S
雏鸡胚胎原始条纹的形成，除了条纹本身细胞的前后运动外，还涉及到条纹外侧细胞的显著协调运动。观察到条纹侧面的细胞经历了“波罗奈运动”，即两个大的反向旋转的漩涡，使人想起流体中的漩涡。在这篇文章中，我们提出了一种机制，这种机制依赖于上胚层后部偶极构型的细胞发出的趋化信号。趋化偶极子由发射化学引诱剂和化学排斥剂的细胞的相邻区域组成。我们使用趋化性和静电学之间的数学类比来激发这一想法，并使用大规模计算机模拟来测试这一想法。我们使用亚细胞元件模型实现了对邻近的机械相互作用和趋化梯度的主动细胞响应。模拟结果表明，细胞运动出现了大尺度的旋涡。旋涡形成的长度和时间尺度与实验数据吻合较好。我们还对趋化偶极机制的稳健性进行了定量估计，这表明，假设只有1%的细胞群体参与信号发射，该机制对趋化参数的变化有约10%的误差容忍度。对于发射信号的更大数量的细胞，这种耐受性会增加。
Primitive streak formation in the chick embryo involves significant coordinated cell movement lateral to the streak, in addition to the posterior–anterior movement of cells in the streak proper. Cells lateral to the streak are observed to undergo'polonaise movements', ie two large counter-rotating vortices, reminiscent of eddies in a fluid. In this paper, we propose a mechanism for these movement patterns which relies on chemotactic signals emitted by a dipolar configuration of cells in the posterior region of the epiblast. The'chemotactic dipole'consists of adjacent regions of cells emitting chemo-attractants and chemo-repellents. We motivate this idea using a mathematical analogy between chemotaxis and electrostatics, and test this idea using large-scale computer simulations. We implement active cell response to both neighboring mechanical interactions and chemotactic gradients using the Subcellular Element Model. Simulations show the emergence of large-scale vortices of cell movement. The length and time scales of vortex formation are in reasonable agreement with experimental data. We also provide quantitative estimates for the robustness of the chemotaxis dipole mechanism, which indicate that the mechanism has an error tolerance of about 10% to variation in chemotactic parameters, assuming that only 1% of the cell population is involved in emitting signals. This tolerance increases for larger populations of cells emitting signals.