Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany; Max Planck Institute for the Physics of Complex Systems, 01187, Dresden, Germany; Tata Institute of Fundamental Research, 400005, Mumbai, India.
Dev Biol. 2020 Apr 1;460(1):55-69. doi: 10.1016/j.ydbio.2019.03.008. Epub 2019 Mar 27.
During vertebrate somitogenesis an inherent segmentation clock coordinates the spatiotemporal signaling to generate segmented structures that pattern the body axis. Using our experimental and quantitative approach, we study the cell movements and the genetic oscillations of her1 expression level at single-cell resolution simultaneously and scale up to the entire pre-somitic mesoderm (PSM) tissue. From the experimentally determined phases of PSM cellular oscillators, we deduced an in vivo frequency profile gradient along the anterior-posterior PSM axis and inferred precise mathematical relations between spatial cell-level period and tissue-level somitogenesis period. We also confirmed a gradient in the relative velocities of cellular oscillators along the axis. The phase order parameter within an ensemble of oscillators revealed the degree of synchronization in the tailbud and the posterior PSM being only partial, whereas synchronization can be almost complete in the presumptive somite region but with temporal oscillations. Collectively, the degree of synchronization itself, possibly regulated by cell movement and the synchronized temporal phase of the transiently expressed clock protein Her1, can be an additional control mechanism for making precise somite boundaries.
在脊椎动物体节发生过程中，内在的分段时钟协调时空信号，生成模式身体轴的分段结构。使用我们的实验和定量方法，我们同时以单细胞分辨率研究 her1 表达水平的细胞运动和遗传振荡，并扩展到整个前体节中胚层 (PSM) 组织。从实验确定的 PSM 细胞振荡器相位中，我们推断出沿前后 PSM 轴的体内频率分布梯度，并推断出空间细胞级周期和组织级体节发生周期之间的精确数学关系。我们还证实了振荡器沿轴的相对速度存在梯度。振荡器集合内的相位顺序参数揭示了尾部和后 PSM 中的同步程度只是部分的，而在假定的体节区域中可以几乎完全同步，但存在时间振荡。总的来说，同步程度本身，可能受到细胞运动和瞬时表达时钟蛋白 Her1 的同步时间相位的调节，可能是用于精确形成体节边界的附加控制机制。
