Hamada Hiroshi
Graduate School of Frontier Bioscience, Osaka University, 1-3 Yamada-oka, Suita, Osaka, 565-0871, Japan
Our body possesses three body axes, anteroposterior, dorsoventral, and left-right (L-R) axes. L-R asymmetry is achieved by three consecutive steps: symmetry breaking at the node, differential patterning of the lateral plate by a signaling molecule Nodal, and finally situs-specific organogenesis. Breaking of L-R symmetry in the mouse embryo takes place in the ventral node, where two types of cilia are found. Whereas centrally located motile cilia generate a leftward fluid flow, peripherally located immotile cilia sense a flow-dependent signal. Although Ca signaling is implicated in flow sensing, it is still not clear what triggers Ca signaling, a determinant molecule transported by the flow or mechanical force induced by the flow.
我们的身体具有三个体轴，即前后轴、背腹轴和左右（L-R）轴。左右不对称是通过三个连续步骤实现的：在节点处打破对称性、由信号分子Nodal对侧板进行差异模式化，以及最终特定位置的器官发生。小鼠胚胎中左右对称性的打破发生在腹侧节点，在那里发现了两种类型的纤毛。位于中央的运动纤毛产生向左的液流，而位于周边的不运动纤毛感知依赖于液流的信号。尽管钙信号传导与液流感知有关，但仍不清楚是什么触发了钙信号传导，是由液流运输的决定分子还是由液流诱导的机械力。
