Liu Ziyi, Shpak Elena D, Hong Tian
Graduate School of Genome Science and Technology, The University of Tennessee, Knoxville, TN, United States.
Department of Biochemistry & Cellular and Molecular Biology, The University of Tennessee, Knoxville, TN, United States.
Comput Struct Biotechnol J. 2020 Nov 21;18:3877-3889. doi: 10.1016/j.csbj.2020.11.017. eCollection 2020.
The shoot apical meristem (SAM) is the primary stem cell niche in plant shoots. Stem cells in the SAM are controlled by an intricate regulatory network, including negative feedback between WUSCHEL (WUS) and CLAVATA3 (CLV3). Recently, we identified a group of signals, Epidermal Patterning Factor-Like (EPFL) proteins, that are produced at the peripheral region and are important for SAM homeostasis. Here, we present a mathematical model for the SAM regulatory network. The model revealed that the SAM uses EPFL and signals such as HAIRY MERISTEM from the middle in a synergistic manner to constrain both and . We found that interconnected negative and positive feedbacks between WUS and CLV3 ensure stable expression in the SAM when facing perturbations, and the positive feedback loop also maintains distinct cell populations containing and cells in the apical-basal direction. Furthermore, systematic perturbations of the parameters revealed a tradeoff between optimizations of multiple patterning features. Our results provide a holistic view of the regulation of SAM patterning in multiple dimensions. They give insights into how integrates signals from lateral and apical-basal axes to control the SAM patterning, and they shed light into design principles that may be widely useful for understanding regulatory networks of stem cell niche.
茎尖分生组织（SAM）是植物茎中的主要干细胞龛。SAM中的干细胞受一个复杂的调控网络控制，包括WUSCHEL（WUS）和CLAVATA3（CLV3）之间的负反馈。最近，我们鉴定出一组信号，即表皮模式因子样（EPFL）蛋白，它们在周边区域产生，对SAM的稳态很重要。在此，我们提出了一个SAM调控网络的数学模型。该模型表明，SAM以协同方式利用EPFL和来自中间区域的如HAIRY MERISTEM等信号来限制两者。我们发现，WUS和CLV3之间相互连接的负反馈和正反馈在面对扰动时确保了SAM中稳定的表达，并且正反馈回路还在顶 - 基方向上维持了包含细胞和细胞的不同细胞群体。此外，对参数的系统扰动揭示了多种模式特征优化之间的权衡。我们的结果提供了对SAM模式调控在多个维度上的整体视图。它们深入了解了如何整合来自侧轴和顶 - 基轴的信号来控制SAM模式，并且揭示了可能广泛用于理解干细胞龛调控网络的设计原则。
