Live imaging of individual cell divisions in mouse neuroepithelium shows asymmetry in cilium formation and Sonic hedgehog response.

Primary cilia are microtubule-based sensory organelles that play important roles in developmental signaling pathways. Recent work demonstrated that, in cell culture, the daughter cell that inherits the older mother centriole generates a primary cilium and responds to external stimuli prior to its sister cell. This asynchrony in timing of cilia formation could be especially critical during development as cell divisions are required for both differentiation and maintenance of progenitor cell niches. Here we integrate several fluorescent markers and use ex vivo live imaging of a single cell division within the mouse E8.5 neuroepithelium to reveal both the formation of a primary cilium and the transcriptional response to Sonic hedgehog in the daughter cells. We show that, upon cell division, cilia formation and the Sonic hedgehog response are asynchronous between the daughter cells. Our results demonstrate that we can directly observe single cell divisions within the developing neuroepithelium and concomitantly monitor cilium formation or Sonic hedgehog response. We expect this method to be especially powerful in examining whether cellular behavior can lead to both differentiation and maintenance of cells in a progenitor niche.

初级纤毛是基于微管的感觉细胞器，在发育信号通路中发挥重要作用。近期的研究表明，在细胞培养中，继承较老的母中心粒的子细胞会产生初级纤毛，并在其姐妹细胞之前对外部刺激作出反应。纤毛形成时间的这种异步性在发育过程中可能尤为关键，因为细胞分裂对于祖细胞生态位的分化和维持都是必需的。 在此，我们整合了几种荧光标记，并对小鼠胚胎第8.5天的神经上皮内的单个细胞分裂进行体外活体成像，以揭示子细胞中初级纤毛的形成以及对音猬因子的转录反应。 我们表明，在细胞分裂时，子细胞之间纤毛的形成和对音猬因子的反应是异步的。 我们的研究结果表明，我们可以直接观察发育中的神经上皮内的单个细胞分裂，并同时监测纤毛的形成或对音猬因子的反应。我们期望这种方法在研究细胞行为是否能导致祖细胞生态位中细胞的分化和维持方面特别有效。