Termination of asymmetric cell division and differentiation of stomata
Termination of asymmetric cell division and differentiation of stomata
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DOI：
10.1038/nature05467
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发表时间：
2007-02-01
期刊：
影响因子：
64.8
通讯作者：
Torii, Keiko U.
中科院分区：
文献类型：
--
作者：
Pillitteri, Lynn Jo;Sloan, Daniel B.;Torii, Keiko U.
气孔由一对保护细胞组成，它们调节植物和大气之间的气体和水蒸气交换。气孔前体细胞-分生组织样细胞-具有短暂的干细胞样特性，在进一步分化之前经历几轮不对称分裂。本文报道拟南芥基本螺旋-环-螺旋（bHLH）蛋白MUTE是分生组织形态转变的关键开关。在没有MUTE的情况下，分生组织在过度不对称分裂后流产，无法分化气孔。组成性过表达的MUTE导致整个表皮采用保护细胞身份。MUTE有两个类似物：保护细胞形态发生的调节因子FAMA和无言（SPCH）。我们发现SPCH指导了第一次不对称分裂，从而启动了气孔谱系。SPCH、MUTE和FAMA bHLH蛋白共同控制气孔发育的三个连续步骤：起始、分生组织分化和保护细胞形态发生。我们的发现强调了密切相关的bHLHs在植物和动物细胞类型分化中的作用。
Stomata consist of a pair of guard cells that mediate gas and water-vapour exchange between plants and the atmosphere. Stomatal precursor cells - meristemoids - possess a transient stem-cell-like property and undergo several rounds of asymmetric divisions before further differentiation. Here we report that the Arabidopsis thaliana basic helix - loop - helix ( bHLH) protein MUTE is a key switch for meristemoid fate transition. In the absence of MUTE, meristemoids abort after excessive asymmetric divisions and fail to differentiate stomata. Constitutive overexpression of MUTE directs the entire epidermis to adopt guard cell identity. MUTE has two paralogues: FAMA, a regulator of guard cell morphogenesis, and SPEECHLESS (SPCH). We show that SPCH directs the first asymmetric division that initiates stomatal lineage. Together, SPCH, MUTE and FAMA bHLH proteins control stomatal development at three consecutive steps: initiation, meristemoid differentiation and guard cell morphogenesis. Our findings highlight the roles of closely related bHLHs in cell type differentiation in plants and animals.