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Current Biology:小立碗藓分枝起始时核定位与不对称细胞分裂的调控机制

已有 432 次阅读 2020-5-31 09:56 |个人分类:每日摘要|系统分类:论文交流

Control Nuclear Positioning and Asymmetric Cell Division during Physcomitrella patens Branching

第一作者Peishan Yi


通讯作者Peishan Yi


背景回顾Branching morphogenesis is a widely used mechanism for development. In plants, it is initiated by the emergence of a new growth axis, which is of particular importance for plants to explore space and access resources. Branches can emerge either from a single cell or from a group of cells. In both cases, the mother cells that initiate branching must undergo dynamic morphological changes and/or adopt oriented asymmetric cell divisions (ACDs) to establish the new growth direction.

提出问题:However, the underlying mechanisms are not fully understood.

主要发现:Here, using the bryophyte moss Physcomitrella patens as a model, we show that side-branch formation in P. patens protonemata requires coordinated polarized cell expansion, directional nuclear migration, and orientated ACD.

By combining pharmacological experiments, long-term time-lapse imaging, and genetic analyses, we demonstrate that Rho of plants (ROPGTPases and actin are essential for cell polarization and local cell expansion (bulging). The growing bulge acts as a prerequisite signal to guide long-distance microtubule (MT)-dependent nuclear migration, which determines the asymmetric positioning of the division plane. MTs play an essential role in nuclear migration but are less involved in bulge formation.

结论:Hence, cell polarity and cytoskeletal elements act cooperatively to modulate cell morphology and nuclear positioning during branch initiation.

展望:We propose that polarity-triggered nuclear positioning and ACD comprise a fundamental mechanism for increasing multicellularity and tissue complexity during plant morphogenesis.


Yi and Goshima investigate branch initiation in the moss P. patens protonemata. The study shows that ROP GTPases and actin initiate the formation of polarized bulges in the pre-branching cells, which in turn directs microtubuledependent nuclear migration and subsequent asymmetric cell division.

 摘  要 

分枝形态发生是一个在发育过程中被广泛利用的机制。在植物中,分枝起始于一个新的生长轴的出现,这对于植物占据空间和获取资源都非常重要。分枝可以形成于单个细胞,也可以形成于一个细胞群。无论是何种情况,起始分枝的母细胞都必须经历动态的形态变化或者是通过定向的不对称细胞分裂来建立新的生长方向。然而,该过程背后的分子调控机制还不清楚。本文中,作者利用苔藓植物小立碗藓作为模式植物,研究发现小立碗藓侧枝的形成需要协调的极性细胞扩张、方向性细胞核迁移以及定向的不对称细胞分裂。通过结合药理试验、长期延时成像以及遗传分析,作者发现ROP GTPase和肌动蛋白对于细胞极性和局部细胞扩张是必需的。小立碗藓正在生长的鼓包(bulge)是指导长距离微管介导的细胞核迁移的先决信号,从而决定了细胞板的不对称定位。微管在细胞核迁移过程中发挥了至关重要的作用,但并不过多参与鼓包的形成。因此,细胞极性与细胞骨架成分协调合作,在分枝起始时调整细胞的形态和细胞核的定位,作者提出极性诱导的核定位和不对称细胞分裂组成了一个基础机制,在植物的形态发生时作用于多细胞性和组织复杂性。

doi: 10.1016/j.cub.2020.05.022

Journal: Current Biology

Published date: May 28, 2020




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