A Cycloheximide-Sensitive Step in Transverse Microtubule Array Patterning
A Cycloheximide-Sensitive Step in Transverse Microtubule Array Patterning
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DOI：
10.1104/pp.18.00672
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发表时间：
2018-10-01
期刊：
影响因子：
7.4
通讯作者：
Shaw, Sidney L.
中科院分区：
文献类型：
--
作者：
Elliott, Andrew;Shaw, Sidney L.
组织内单个细胞的生长特性决定植物形态，而细胞骨架的组织，特别是微管阵列，决定细胞的生长特性。我们研究了轴向生长的拟南芥（Arabidopsis thaliana）表皮下胚轴细胞中横向微管阵列模式形成的机制。使用定量成像方法，我们映射到一个横向coaligned图案诱导生长素和赤霉素后，皮层微管阵列的过渡。激素诱导导致早期损失的微管加端密度和旋转倾斜的模式。诱导后30分钟开始，横向微管出现在细胞的中区同时纵向聚合物的损失，最终进展顶部和基部重塑阵列图案。基于时间和已知的信号通路，我们测试了假设，后期事件需要从头基因表达，因此，构成了横向图案的遗传控制水平。我们发现，翻译抑制剂放线菌酮（CHX）的存在下，导致在一个选择性和可逆的损失的横向模式，被替换为放射状风车阵列表现出分裂双极架构为中心的细胞的中间区。使用激素诱导和CHX的实验表明，风车阵列发生时，横向微管增加在中间区，但纵向微管分裂双极架构不受抑制。我们建议，一个关键的监管机制，用于创建横向微管coalignment轴向生长的下胚轴涉及的表达的CHX敏感因子，其作用是抑制成核的纵向取向的聚合物。
The growth properties of individual cells within a tissue determine plant morphology, and the organization of the cytoskeleton, particularly the microtubule arrays, determines cellular growth properties. We investigated the mechanisms governing the formation of transverse microtubule array patterns in axially growing Arabidopsis (Arabidopsis thaliana) epidermal hypocotyl cells. Using quantitative imaging approaches, we mapped the transition of the cortical microtubule arrays into a transverse coaligned pattern after induction with auxin and gibberellic acid. Hormone induction led to an early loss of microtubule plus end density and a rotation toward oblique patterns. Beginning 30 min after induction, transverse microtubules appeared at the cell's midzone concurrently with the loss of longitudinal polymers, eventually progressing apically and basally to remodel the array pattern. Based on the timing and known hormone-signaling pathways, we tested the hypothesis that the later events require de novo gene expression and, thus, constitute a level of genetic control over transverse patterning. We found that the presence of the translation inhibitor cycloheximide (CHX) resulted in a selective and reversible loss of transverse patterns that were replaced with radial-like pinwheel arrays exhibiting a split bipolar architecture centered at the cell's midzone. Experiments using hormone induction and CHX revealed that pinwheel arrays occur when transverse microtubules increase at the midzone but longitudinal microtubules in the split bipolar architecture are not suppressed. We propose that a key regulatory mechanism for creating the transverse microtubule coalignment in axially growing hypocotyls involves the expression of a CHX-sensitive factor that acts to suppress the nucleation of the longitudinally oriented polymers.