GLABRA2 Directly Suppresses Basic Helix-Loop-Helix Transcription Factor Genes with Diverse Functions in Root Hair Development.
GLABRA2 Directly Suppresses Basic Helix-Loop-Helix Transcription Factor Genes with Diverse Functions in Root Hair Development.
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DOI：
10.1105/tpc.15.00607
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
Aoyama T
中科院分区：
文献类型：
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作者：
Lin Q;Ohashi Y;Kato M;Tsuge T;Gu H;Qu LJ;Aoyama T
拟南芥 GLABRA2 (GL2) 基因编码参与各种表皮组织细胞分化的转录因子。在根毛图案形成过程中，GL2 抑制非毛细胞中的根毛发育，充当细胞命运决定和细胞分化的基因调控网络之间的节点。尽管 GL2 功能很重要，但其分子基础仍然不清楚，因为导致细胞分化网络的 GL2 靶基因尚不清楚。我们使用转录和翻译后诱导系统确定了五个基本螺旋-环-螺旋 (bHLH) 转录因子基因——ROOT HAIR DEFECTIVE6 (RHD6)、RHD6-LIKE1 (RSL1)、RSL2、LjRHL1-LIKE1 (LRL1) 和 LRL2——作为 GL2 直接靶标。染色质免疫沉淀分析证实 GL2 与植物中这些基因的上游区域结合。报告基因分析表明，这些基因在根毛发育的各个阶段表达，并在非毛细胞中被 GL2 抑制。 GL2 启动子驱动的 LRL1 和 LRL2 绿色荧光蛋白融合体（而非其他 bHLH 蛋白的融合体）赋予非毛细胞根毛发育。这些结果表明GL2直接抑制在根毛发育中具有多种功能的bHLH基因。
The Arabidopsis thaliana GLABRA2 (GL2) gene encodes a transcription factor involved in the cell differentiation of various epidermal tissues. During root hair pattern formation, GL2 suppresses root hair development in non-hair cells, acting as a node between the gene regulatory networks for cell fate determination and cell differentiation. Despite the importance of GL2 function, its molecular basis remains obscure because the GL2 target genes leading to the network for cell differentiation are unknown. We identified five basic helix-loop-helix (bHLH) transcription factor genes—ROOT HAIR DEFECTIVE6 (RHD6), RHD6-LIKE1 (RSL1), RSL2, LjRHL1-LIKE1 (LRL1), and LRL2—as GL2 direct targets using transcriptional and post-translational induction systems. Chromatin immunoprecipitation analysis confirmed GL2 binding to upstream regions of these genes in planta. Reporter gene analyses showed that these genes are expressed in various stages of root hair development and are suppressed by GL2 in non-hair cells. GL2 promoter-driven green fluorescent protein fusions of LRL1 and LRL2, but not those of the other bHLH proteins, conferred root hair development on non-hair cells. These results indicate that GL2 directly suppresses bHLH genes with diverse functions in root hair development.