Department of Physics, McGill University, Montreal, Canada.
Division of Developmental Biology, Department of Biology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Elife. 2020 Aug 10;9:e55778. doi: 10.7554/eLife.55778.
During development, cells gradually assume specialized fates via changes of transcriptional dynamics, sometimes even within the same developmental stage. For anterior-posterior (AP) patterning in metazoans, it has been suggested that the gradual transition from a dynamic genetic regime to a static one is encoded by different transcriptional modules. In that case, the static regime has an essential role in pattern formation in addition to its maintenance function. In this work, we introduce a geometric approach to study such transition. We exhibit two types of genetic regime transitions arising through local or global bifurcations, respectively. We find that the global bifurcation type is more generic, more robust, and better preserves dynamical information. This could parsimoniously explain common features of metazoan segmentation, such as changes of periods leading to waves of gene expressions, 'speed/frequency-gradient' dynamics, and changes of wave patterns. Geometric approaches appear as possible alternatives to gene regulatory networks to understand development.
在发育过程中，细胞通过转录动力学的变化逐渐获得特化命运，有时甚至在同一发育阶段也是如此。对于后生动物的前后（AP）模式形成，有人提出，从动态遗传状态到静态遗传状态的逐渐转变是由不同的转录模块编码的。在这种情况下，除了维持功能外，静态状态在模式形成中起着至关重要的作用。在这项工作中，我们引入了一种几何方法来研究这种转变。我们展示了分别通过局部或全局分叉产生的两种遗传状态转变类型。我们发现，全局分叉类型更通用、更稳健，并且更好地保留了动力学信息。这可以简洁地解释后生动物分节的常见特征，例如导致基因表达波的周期变化、“速度/频率梯度”动力学以及波型变化。几何方法似乎是理解发育的替代基因调控网络的可能方法。
