Cole Melanie, Chandler John, Weijers Dolf, Jacobs Bianca, Comelli Petra, Werr Wolfgang
Institute of Developmental Biology, University of Cologne, Gyrhofstrasse 17, 50931 Cologne, Germany.
Development. 2009 May;136(10):1643-51. doi: 10.1242/dev.032177. Epub 2009 Apr 15.
DORNROSCHEN (DRN), which encodes a member of the AP2-type transcription factor family, contributes to auxin transport and perception in the Arabidopsis embryo. Live imaging performed with transcriptional or translational GFP fusions shows DRN to be activated in the apical cell after the first zygotic division, to act cell-autonomously and to be expressed in single cells extending laterally from the apical shoot stem-cell zone at the position of incipient leaf primordia. Here, we show that the Auxin response factor (ARF) MONOPTEROS (MP) directly controls DRN transcription in the tips of the embryonic cotyledons, which depends on the presence of canonical Auxin response elements (AuxREs), potential ARF-binding sites flanking the DRN transcription unit. Chromatin immunoprecipitation experiments show that MP binds in vivo to two AuxRE-spanning fragments in the DRN promoter, and that MP is required for expression of DRN in cotyledon tips. Hence, DRN represents a direct target of MP and functions downstream of MP in cotyledon development.
多萝西（DRN）编码AP2型转录因子家族的一个成员，在拟南芥胚胎中参与生长素运输和感知。用转录或翻译GFP融合蛋白进行的实时成像显示，DRN在第一次合子分裂后在顶端细胞中被激活，以细胞自主方式起作用，并在从顶端茎干细胞区横向延伸的单细胞中表达，这些单细胞位于初始叶原基的位置。在这里，我们表明生长素响应因子（ARF）单翼子叶（MP）直接控制胚胎子叶尖端的DRN转录，这取决于典型生长素响应元件（AuxREs）的存在，即DRN转录单元两侧的潜在ARF结合位点。染色质免疫沉淀实验表明，MP在体内与DRN启动子中的两个跨越AuxRE的片段结合，并且MP是子叶尖端DRN表达所必需的。因此，DRN代表MP的直接靶标，并在子叶发育中在MP下游起作用。
