Indian Institute of Science Education and Research (IISER), Pune 411008, India; IISER, Thiruvananthapuram 695551, India.
Indian Institute of Science Education and Research (IISER), Pune 411008, India; IISER, Thiruvananthapuram 695551, India.
Dev Cell. 2022 Sep 12;57(17):2063-2080.e10. doi: 10.1016/j.devcel.2022.07.017. Epub 2022 Aug 23.
Cellular heterogeneity is a hallmark of multicellular organisms. During shoot regeneration from undifferentiated callus, only a select few cells, called progenitors, develop into shoot. How these cells are selected and what governs their subsequent progression to a patterned organ system is unknown. Using Arabidopsis thaliana, we show that it is not just the abundance of stem cell regulators but rather the localization pattern of polarity proteins that predicts the progenitor's fate. A shoot-promoting factor, CUC2, activated the expression of the cell-wall-loosening enzyme, XTH9, solely in a shell of cells surrounding the progenitor, causing different mechanical stresses in these cells. This mechanical conflict then activates cell polarity in progenitors to promote meristem formation. Interestingly, genetic or physical perturbations to cells surrounding the progenitor impaired the progenitor and vice versa. These suggest a feedback loop between progenitors and their neighbors for shoot regeneration in the absence of tissue-patterning cues.
细胞异质性是多细胞生物的一个标志。在不定芽从愈伤组织再生的过程中，只有少数被称为祖细胞的细胞发育成芽。这些细胞是如何被选择的，以及什么决定了它们随后向有模式的器官系统的进展，目前还不清楚。利用拟南芥，我们表明，预测祖细胞命运的不仅仅是干细胞调控因子的丰度，而是极性蛋白的定位模式。一个促进芽形成的因子 CUC2，仅在围绕祖细胞的细胞壳中激活细胞壁松弛酶 XTH9 的表达，导致这些细胞中的机械应力不同。这种机械冲突随后激活了祖细胞中的细胞极性，以促进分生组织的形成。有趣的是，对祖细胞周围细胞的遗传或物理干扰会损害祖细胞，反之亦然。这表明在没有组织模式线索的情况下，祖细胞与其相邻细胞之间存在一个反馈回路，以促进芽的再生。
