BZU2/ZmMUTE controls symmetrical division of guard mother cell and specifies neighbor cell fate in maize
BZU2/ZmMUTE controls symmetrical division of guard mother cell and specifies neighbor cell fate in maize
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BZU2/ZmMUTE 控制玉米保卫母细胞的对称分裂并指定相邻细胞的命运
DOI：
10.1371/journal.pgen.1008377
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发表时间：
2019-08-01
期刊：
影响因子：
4.5
通讯作者：
Song, Chun-Peng
中科院分区：
文献类型：
--
作者：
Wang, Hongliang;Guo, Siyi;Song, Chun-Peng
相邻细胞层的细胞间通讯决定细胞命运和极性，从而协调组织规范和分化。在这里，我们使用玉米气孔器作为模型来研究细胞命运的决定。 ZmBZU2（bizui2、bzu2）突变导致辅助细胞（SC）和正常保卫细胞（GC）完全缺失，导致成熟气孔复合体形成失败。辅助母细胞 (SMC) 和保卫母细胞 (GMC) 之间界面的核极化和肌动蛋白积累是不对称细胞分裂的重要先决条件，但在 Zmbzu2 突变体中并未发生。 ZmBZU2 编码基本螺旋-环-螺旋 (bHLH) 转录因子，它是拟南芥中 AtMUTE 的直向同源物 (BZU2/ZmMUTE)。我们发现许多与气孔发育有关的基因受 BZU2/ZmMUTE 转录调控。特别是，BZU2/ZmMUTE 直接与 PAN1 和 PAN2 的启动子结合，PAN1 和 PAN2 是原真皮细胞命运和 SMC 极化的两个早期调节因子，与 bzu2-1 突变体中观察到的这些基因的低转录水平一致。 BZU2/ZmMUTE 具有与二穗短柄草中的 BdMUTE 相似的细胞间迁移特性。出乎意料的是，从不对称分裂阶段到GMC分裂阶段，尤其是SMC建立阶段，BZU2/ZmMUTE在GMC中表达。总而言之，这些数据表明 BZU2/ZmMUTE 是 SMC 极化和分化的早期事件以及 GMC 最后对称分裂以产生两个 GC 所必需的，并且是通过细胞间通讯来决定其相邻细胞命运的主要决定因素。
Intercellular communication in adjacent cell layers determines cell fate and polarity, thus orchestrating tissue specification and differentiation. Here we use the maize stomatal apparatus as a model to investigate cell fate determination. Mutations in ZmBZU2 (bizui2, bzu2) confer a complete absence of subsidiary cells (SCs) and normal guard cells (GCs), leading to failure of formation of mature stomatal complexes. Nuclear polarization and actin accumulation at the interface between subsidiary mother cells (SMCs) and guard mother cells (GMCs), an essential pre-requisite for asymmetric cell division, did not occur in Zmbzu2 mutants. ZmBZU2 encodes a basic helix-loop-helix (bHLH) transcription factor, which is an ortholog of AtMUTE in Arabidopsis (BZU2/ZmMUTE). We found that a number of genes implicated in stomatal development are transcriptionally regulated by BZU2/ZmMUTE. In particular, BZU2/ZmMUTE directly binds to the promoters of PAN1 and PAN2, two early regulators of protodermal cell fate and SMC polarization, consistent with the low levels of transcription of these genes observed in bzu2-1 mutants. BZU2/ZmMUTE has the cell-to-cell mobility characteristic similar to that of BdMUTE in Brachypodium distachyon. Unexpectedly, BZU2/ZmMUTE is expressed in GMC from the asymmetric division stage to the GMC division stage, and especially in the SMC establishment stage. Taken together, these data imply that BZU2/ZmMUTE is required for early events in SMC polarization and differentiation as well as for the last symmetrical division of GMCs to produce the two GCs, and is a master determinant of the cell fate of its neighbors through cell-to-cell communication.