Chua Yii Leng, Channelière Stéphanie, Mott Ellie, Gray John C
Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK.
Genes Dev. 2005 Sep 15;19(18):2245-54. doi: 10.1101/gad.352005.
The transition from the juvenile to the mature phase during vegetative development in plants is characterized by changes in leaf shape. We show that GENERAL TRANSCRIPTION FACTOR GROUP E6 (GTE6) regulates differences in leaf patterning between juvenile and mature leaves in Arabidopsis. GTE6 encodes a novel small bromodomain-containing protein unique to plants. Mutations in GTE6 disrupt the formation of elliptical leaf laminae in mature leaves, whereas overexpression of GTE6 resulted in elongated juvenile leaves. GTE6 positively regulates the expression of ASYMMETRIC LEAVES1 (AS1), which encodes a myb-domain protein that controls proximodistal patterning of leaves. Using chromatin immunoprecipitation (ChIP) assays, we show that GTE6 is associated with the promoter and the start of the transcribed region of AS1 and up-regulates expression of AS1 through acetylation of histones H3 and H4. Genetic studies demonstrated that AS1 is epistatic to GTE6, indicating that GTE6 regulates AS1 during leaf morphogenesis. Chromatin remodeling at AS1 is a key regulatory mechanism in leaf development, which ensures the continual production of mature leaves following juvenile-adult transition, thereby maintaining the identity of the mature vegetative phase.
植物营养生长阶段从幼年期向成熟期的转变以叶片形状的变化为特征。我们发现，通用转录因子E6组（GTE6）调控拟南芥幼叶和成熟叶之间叶片模式的差异。GTE6编码一种植物特有的含新型小溴结构域的蛋白质。GTE6突变会破坏成熟叶中椭圆形叶片的形成，而GTE6的过表达则导致幼叶伸长。GTE6正向调控不对称叶片1（AS1）的表达，AS1编码一种控制叶片近远轴模式的Myb结构域蛋白。通过染色质免疫沉淀（ChIP）分析，我们发现GTE6与AS1的启动子和转录区域起始位点相关联，并通过组蛋白H3和H4的乙酰化上调AS1的表达。遗传学研究表明，AS1对GTE6呈上位性，表明GTE6在叶片形态发生过程中调控AS1。AS1处的染色质重塑是叶片发育中的关键调控机制，它确保了幼年期向成年期转变后成熟叶的持续产生，从而维持成熟营养阶段的特征。
