Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases.
Brassinosteroids control root epidermal cell fate via direct regulation of a MYB-bHLH-WD40 complex by GSK3-like kinases.
复制标题
油菜素类固醇通过 GSK3 样激酶直接调节 MYB-bHLH-WD40 复合物来控制根表皮细胞的命运
作者：
Cheng Y;Zhu W;Chen Y;Ito S;Asami T;Wang X
在拟南芥中，根毛和非毛细胞的命运是由MYB-bHLH-WD 40转录复合体决定的，并受到许多内部和环境因素的调节。维生素类固醇通过未知的机制在调节根毛特化中发挥重要作用。在这里，我们系统地检查了油菜素类固醇相关突变体的根毛表型，发现油菜素类固醇信号传导通过GSK 3样激酶或上游成分抑制根毛形成。我们发现，随着油菜素类固醇信号的增强，非毛细胞的细胞命运标志物GL 2在毛细胞中异位表达，而当油菜素类固醇信号减少时，其在非毛细胞中的表达受到抑制。遗传分析表明，油菜素类固醇调节的根表皮细胞图案依赖于WER-GL 3/EGL 3-TTG 1转录复合物。其中一种GSK 3样激酶BIN 2与EGL 3相互作用并磷酸化EGL 3，并且在磷酸化位点突变的EGL 3保留在毛细胞核中。BIN 2磷酸化TTG 1以抑制WER-GL 3/EGL 3-TTG 1复合物的活性。因此，我们的研究提供了深入了解油菜素类固醇调节根毛图案的机制。DOI：http://dx.doi.org/10.7554/eLife.02525.001网站
In Arabidopsis, root hair and non-hair cell fates are determined by a MYB-bHLH-WD40 transcriptional complex and are regulated by many internal and environmental cues. Brassinosteroids play important roles in regulating root hair specification by unknown mechanisms. Here, we systematically examined root hair phenotypes in brassinosteroid-related mutants, and found that brassinosteroid signaling inhibits root hair formation through GSK3-like kinases or upstream components. We found that with enhanced brassinosteroid signaling, GL2, a cell fate marker for non-hair cells, is ectopically expressed in hair cells, while its expression in non-hair cells is suppressed when brassinosteroid signaling is reduced. Genetic analysis demonstrated that brassinosteroid-regulated root epidermal cell patterning is dependent on the WER-GL3/EGL3-TTG1 transcriptional complex. One of the GSK3-like kinases, BIN2, interacted with and phosphorylated EGL3, and EGL3s mutated at phosphorylation sites were retained in hair cell nuclei. BIN2 phosphorylated TTG1 to inhibit the activity of the WER-GL3/EGL3-TTG1 complex. Thus, our study provides insights into the mechanism of brassinosteroid regulation of root hair patterning. DOI: http://dx.doi.org/10.7554/eLife.02525.001