Refined understanding of the preprophase band Because plant cells do not move, plant tissues are constructed according to how they place the divisions of their constituent cells. Schaefer et al. found a mutation in the model plant Arabidopsis that abolishes a visible precursor of cell division, the preprophase band. Despite loss of the band—previously thought essential to define the division plane—the general orientations of cell division planes in the roots of these plants were normal. However, individual division orientations showed more variance than normal. Thus, the preprophase band serves to focus and refine the final orientation of the nascent cell division plane. Science, this issue p. 186 A structure thought to be required for division plane selection in plants merely refines division plane position by reducing spindle rotation. Controlling cell division plane orientation is essential for morphogenesis in multicellular organisms. In plant cells, the future cortical division plane is marked before mitotic entry by the preprophase band (PPB). Here, we characterized an Arabidopsis trm (TON1 Recruiting Motif) mutant that impairs PPB formation but does not affect interphase microtubules. Unexpectedly, PPB disruption neither abolished the capacity of root cells to define a cortical division zone nor induced aberrant cell division patterns but rather caused a loss of precision in cell division orientation. Our results advocate for a reassessment of PPB function and division plane determination in plants and show that a main output of this microtubule array is to limit spindle rotations in order to increase the robustness of cell division.

中文翻译：

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微管的前期带控制植物分裂方向的稳健性

对前期带的精细理解 因为植物细胞不会移动，所以植物组织是根据它们如何放置组成细胞的分裂来构建的。舍费尔等人。在模式植物拟南芥中发现了一种突变，该突变消除了细胞分裂的可见前体，即前期带。尽管该带丢失了——以前被认为是定义分裂平面所必需的——但这些植物根部细胞分裂平面的一般方向是正常的。然而，个体划分方向显示出比正常情况更多的差异。因此，前期带用于聚焦和细化新生细胞分裂平面的最终方向。科学，这个问题 p。186 一种被认为是工厂中分割平面选择所需的结构，只是通过减少主轴旋转来细化分割平面的位置。控制细胞分裂平面方向对于多细胞生物的形态发生至关重要。在植物细胞中，未来的皮质分裂平面在有丝分裂进入前被前期带 (PPB) 标记。在这里，我们表征了一种拟南芥 trm（TON1 Recruiting Motif）突变体，该突变体会损害 PPB 形成但不影响相间微管。出乎意料的是，PPB 破坏既没有消除根细胞定义皮质分裂区的能力，也没有诱导异常的细胞分裂模式，而是导致细胞分裂方向精度的损失。我们的结果主张重新评估植物中 PPB 功能和分裂平面的确定，并表明该微管阵列的主要输出是限制纺锤体旋转以增加细胞分裂的稳健性。