The Basic Helix-Loop-Helix Transcription Factor MYC2 Directly Represses PLETHORA Expression during Jasmonate-Mediated Modulation of the Root Stem Cell Niche in Arabidopsis
The Basic Helix-Loop-Helix Transcription Factor MYC2 Directly Represses PLETHORA Expression during Jasmonate-Mediated Modulation of the Root Stem Cell Niche in Arabidopsis
复制标题
碱性螺旋-环-螺旋转录因子 MYC2 在茉莉酸介导的拟南芥根干细胞生态位调节过程中直接抑制 PLETHORA 表达
DOI：
10.1105/tpc.111.089870
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发表时间：
2011-09-01
期刊：
影响因子：
11.6
通讯作者：
Li, Chuanyou
中科院分区：
文献类型：
--
作者：
Chen, Qian;Sun, Jiaqiang;Li, Chuanyou
拟南芥根分生组织中的根干细胞生态位是由四个有丝分裂不活跃的静止细胞和周围有丝分裂活跃的干细胞组成的区域，对根的发育和生长至关重要。我们在这里报告，在茉莉酸诱导的抑制主根生长，茉莉酸降低根分生组织的活动，并导致不规则的QC分裂和柱干细胞分化。因此，茉莉酸降低了AP 2结构域转录因子PLETHORA 1（PLT 1）和PLT 2的表达水平，它们形成了一个发育指导蛋白梯度，并介导了生长素诱导的干细胞生态位维持调节。毫不奇怪，茉莉酸对根干细胞龛维持和PLT表达的影响需要MYC 2/JASMONATE INSENSITIVE 1的功能，MYC 2/JASMONATE INSENSITIVE 1是一种基本的螺旋-环-螺旋转录因子，涉及茉莉酸调节基因表达的多方面。凝胶位移和染色质免疫沉淀实验表明，MYC 2直接结合的PLT 1和PLT 2的启动子，并抑制其表达。我们认为MYC 2介导的PLT表达抑制整合了茉莉酸作用到生长素途径中，调节根分生组织活性和干细胞生态位的维持。本研究阐明了茉莉酸通过与生长调节剂生长素的相互作用诱导抑制根生长的分子框架。
The root stem cell niche, which in the Arabidopsis thaliana root meristem is an area of four mitotically inactive quiescent cells (QCs) and the surrounding mitotically active stem cells, is critical for root development and growth. We report here that during jasmonate-induced inhibition of primary root growth, jasmonate reduces root meristem activity and leads to irregular QC division and columella stem cell differentiation. Consistently, jasmonate reduces the expression levels of the AP2-domain transcription factors PLETHORA1 (PLT1) and PLT2, which form a developmentally instructive protein gradient and mediate auxin-induced regulation of stem cell niche maintenance. Not surprisingly, the effects of jasmonate on root stem cell niche maintenance and PLT expression require the functioning of MYC2/JASMONATE INSENSITIVE1, a basic helixloop-helix transcription factor that involves versatile aspects of jasmonate-regulated gene expression. Gel shift and chromatin immunoprecipitation experiments reveal that MYC2 directly binds the promoters of PLT1 and PLT2 and represses their expression. We propose that MYC2-mediated repression of PLT expression integrates jasmonate action into the auxin pathway in regulating root meristem activity and stem cell niche maintenance. This study illustrates a molecular framework for jasmonate-induced inhibition of root growth through interaction with the growth regulator auxin.