The balance between the MIR164A and CUC2 genes controls leaf margin serration in Arabidopsis
The balance between the MIR164A and CUC2 genes controls leaf margin serration in Arabidopsis
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DOI：
10.1105/tpc.106.045617
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发表时间：
2006-11-01
期刊：
影响因子：
11.6
通讯作者：
Laufs, Patrick
中科院分区：
文献类型：
--
作者：
Nikovics, Krisztina;Blein, Thomas;Laufs, Patrick
杯状子叶1（CUC 1）、CUC 2和CUC 3定义了拟南芥分生组织器官周围的边界域。CUC 1和CUC 2转录物由微小RNA（miRNA）miR 164靶向，miR 164由MIR 164 A、B和C编码。我们发现每个MIR 164被转录以产生大量大小可变的初级miRNA，其在pre-miRNA周围具有局部保守的二级结构。我们确定了MIR 164 A基因的突变，加深了叶缘的锯齿。相比之下，过表达miR 164的植物的叶子具有光滑的边缘。在miR 164抗性CUC 2表达后观察到增强的叶锯齿，但在miR 164抗性CUC 1表达后没有观察到增强的叶锯齿。此外，CUC 2失活消除了mir 164 a突变体和野生型的锯齿，而CUC 1失活没有。因此，CUC 2特异性地控制叶缘发育。CUC 2和MIR 164 A在幼叶原基边缘的重叠结构域中转录，转录逐渐限于叶缘锯齿状的窦。我们认为拟南芥叶缘发育受两步过程控制。首先独立于CUC 2和miR 164确定锯齿图案。然后，共表达的CUC 2和MIR 164 A之间的平衡决定了锯齿的程度。
CUP-SHAPED COTYLEDON1 (CUC1), CUC2, and CUC3 define the boundary domain around organs in the Arabidopsis thaliana meristem. CUC1 and CUC2 transcripts are targeted by a microRNA (miRNA), miR164, encoded by MIR164A, B, and C. We show that each MIR164 is transcribed to generate a large population of primary miRNAs of variable size with a locally conserved secondary structure around the pre-miRNA. We identified mutations in the MIR164A gene that deepen serration of the leaf margin. By contrast, leaves of plants overexpressing miR164 have smooth margins. Enhanced leaf serration was observed following the expression of an miR164-resistant CUC2 but not of an miR164-resistant CUC1. Furthermore, CUC2 inactivation abolished serration in mir164a mutants and the wild type, whereas CUC1 inactivation did not. Thus, CUC2 specifically controls leaf margin development. CUC2 and MIR164A are transcribed in overlapping domains at the margins of young leaf primordia, with transcription gradually restricted to the sinus, where the leaf margins become serrated. We suggest that leaf margin development is controlled by a two-step process in Arabidopsis. The pattern of serration is determined first, independently of CUC2 and miR164. The balance between coexpressed CUC2 and MIR164A then determines the extent of serration.