Mechanism of nodal flow: A conserved symmetry breaking event in left-right axis determination
Mechanism of nodal flow: A conserved symmetry breaking event in left-right axis determination
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DOI：
10.1016/j.cell.2005.04.008
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发表时间：
2005-05-20
期刊：
影响因子：
64.5
通讯作者：
Hirokawa, N
中科院分区：
文献类型：
--
作者：
Okada, Y;Takeda, S;Hirokawa, N
胚外液中的微循环流动对于小鼠胚胎左右轴的初步确定是至关重要的。目前尚不清楚这是否是其他脊椎动物中的保守机制，以及纤毛运动如何产生流动的方向性。在本文中，我们表明，兔和medakafish胚胎也表现出一个在其腹节点的流体流动。在所有的情况下，初级单眼呈现顺时针旋转样运动。在突变小鼠胚胎中观察到的纤毛动力学缺陷支持了这样一种观点，即在类似旋转的跳动过程中纤毛的后倾可以解释纤毛流体的流动。此外，我们表明，这种非对称流可能会产生不对称分布的外源引入的蛋白质，这表明形态梯度作为随后的机制，左右轴的决定。最后，我们的实验和理论特征的条件下，形态梯度可以产生的流动。
The leftward flow in extraembryonic fluid is critical for the initial determination of the left-right axis of mouse embryos. It is unclear if this is a conserved mechanism among other vertebrates and how the directionality of the flow arises from the motion of cilia. In this paper, we show that rabbit and medakafish embryos also exhibit a leftward fluid flow in their ventral nodes. In all cases, primary monocilia present a clockwise rotational-like motion. Observations of defective ciliary dynamics in mutant mouse embryos support the idea that the posterior tilt of the cilia during rotational-like beating can explain the leftward fluid flow. Moreover, we show that this leftward flow may produce asymmetric distribution of exogenously introduced proteins, suggesting morphogen gradients as a subsequent mechanism of left-right axis determination. Finally, we experimentally and theoretically characterize under which conditions a morphogen gradient can arise from the flow.