The TTG1-bHLH-MYB complex controls trichome cell fate and patterning through direct targeting of regulatory loci
The TTG1-bHLH-MYB complex controls trichome cell fate and patterning through direct targeting of regulatory loci
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DOI：
10.1242/dev.016873
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
Ming-hui Zhao;K. Morohashi;Gregory J. Hatlestad;E. Grotewold;A. Lloyd
中科院分区：
文献类型：
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作者：
Ming-hui Zhao;K. Morohashi;Gregory J. Hatlestad;E. Grotewold;A. Lloyd
由bHLH和MYB转录因子组成的三类蛋白质的网络，以及WD 40重复蛋白，透明种皮GLABRA 1（TTG 1），共同激活毛状体的起始和图案化。使用YFP-TTG 1的翻译融合，我们表明，TTG 1的表达无处不在的拟南芥叶片，并优先定位在细胞核的毛状体在所有的发展阶段。使用条件性转基因等位基因，我们证明TTG 1直接靶向与bHLH蛋白GLABRA 3（GL 3）相同的基因。R2 R3-MYB蛋白GLABRA 1（GL 1）与GLABRA 2（GL 2）、透明睾丸GLABRA 2（TTG 2）、CAPRICE（CPC）和三肽和CAPRICE 1增强子（ETC 1）的启动子的体内结合确定这些基因是TTG 1-bHLH-MYB调节复合物的主要转录靶点。通过共沉淀，我们证实TTG 1与GL 3和GL 1在体内缔合，形成复合物。TTG 1和GL 1通过突变而丢失，影响GL 3的亚细胞分布。使用粒子轰击，我们表明，TTG 1，GL 3，GL 1和同源结构域蛋白GL 2不移动相邻的表皮细胞之间，而R3-MYB，CPC，移动到相邻的细胞。这些数据支持一个模型TTG 1复合物直接调节激活剂和阻遏物和运动的阻遏物影响毛状体图案的拟南芥叶。
A network of three classes of proteins consisting of bHLH and MYB transcription factors, and a WD40 repeat protein, TRANSPARENT TESTA GLABRA1 (TTG1), act in concert to activate trichome initiation and patterning. Using YFP-TTG1 translational fusions, we show that TTG1 is expressed ubiquitously in Arabidopsis leaves and is preferentially localized in the nuclei of trichomes at all developmental stages. Using a conditional transgenic allele, we demonstrate that TTG1 directly targets the same genes as the bHLH protein GLABRA3 (GL3). In vivo binding of the R2R3-MYB protein GLABRA1 (GL1) to the promoters of GLABRA2 (GL2), TRANSPARENT TESTA GLABRA2 (TTG2), CAPRICE (CPC) and ENHANCER OF TRIPTYCHON AND CAPRICE1 (ETC1) establishes that these genes are major transcriptional targets for the TTG1-bHLH-MYB regulatory complex. By co-precipitation, we confirm that TTG1 associates with GL3 and GL1 in vivo, forming a complex. The loss of TTG1 and GL1 through mutation, affects the subcellular distribution of GL3. Using particle bombardment, we show that TTG1, GL3, GL1 and the homeodomain protein GL2 do not move between adjacent epidermal cells, while the R3-MYB, CPC, does move to neighboring cells. These data support a model for the TTG1 complex directly regulating activators and repressors and the movement of repressors to affect trichome patterning on the Arabidopsis leaf.