Novel TTG1 Mutants Modify Root-Hair Pattern Formation in Arabidopsis
Novel TTG1 Mutants Modify Root-Hair Pattern Formation in Arabidopsis
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DOI：
10.3389/fpls.2020.00383
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发表时间：
2020-04-07
影响因子：
5.6
通讯作者：
Schiefelbein, John
中科院分区：
文献类型：
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作者：
Long, Yun;Schiefelbein, John
拟南芥根部的根毛和非毛表皮细胞的模式是由一个转录调控网络控制的。中心MYB-bHLH-WD40 （MBW）转录复合体包括WD40-repeat蛋白TRANSPARENT TESTA GLABRA1 （TTG1）。为了阐明TTG1的作用，我们描述了两个新的TTG1突变体的鉴定和分析。这些突变体中的每一个都包含TTG1基因的单个核苷酸变化，导致预测的TTG1蛋白的单个氨基酸替换，并改变根毛模式的形成。令人惊讶的是，这些新的ttg1突变体表现出根毛形成减少，特别是在反复突变（cpc）突变背景下，而不是像报道的强ttg1突变体那样增加根毛形成。我们发现这些突变体的独特表型是由于改变的TTG1蛋白对靶基因表达的不同影响，与与GLABRA3 bHLH伴侣相互作用的能力减弱有关。这些发现表明，在拟南芥根系发育过程中，TTG1在靶基因激活的适当平衡中起着至关重要的作用，从而实现表皮细胞类型的适当模式。
The patterning of root-hair and non-hair epidermal cells in the Arabidopsis root is governed by a network of transcriptional regulators. The central MYB-bHLH-WD40 (MBW) transcriptional complex includes the WD40-repeat protein TRANSPARENT TESTA GLABRA1 (TTG1). To clarify the role of TTG1, we describe the identification and analysis of two new ttg1 mutants. Each of these mutants contains a single nucleotide change in the TTG1 gene, which causes a single amino-acid substitution in the predicted TTG1 protein and alters root-hair pattern formation. Surprisingly, these new ttg1 mutants exhibit decreased root-hair formation, particularly in the caprice (cpc) mutant background, rather than increased root-hair formation as reported for strong ttg1 mutants. We show that the unique phenotype of these mutants is due to differential effects of the altered TTG1 proteins on target gene expression, associated with a weakened ability to interact with its GLABRA3 bHLH partner. These findings demonstrate the crucial role of TTG1 for the appropriate balance of target gene activation to achieve the proper pattern of epidermal cell types during Arabidopsis root development.