Expression profiling of shoot apices of 35S::WOX1:GR seedlings transiently treated with DEX

The WOX1 transcription factor is a multifunctional regulator of lateral-organ development that acts as a transcriptional repressor. WOX1 promotes lamina growth, controls marginal tissue differentiation and is involved in establishment and maintenance of the adaxial-abaxial pattern from the middle domain of leaf primordia. To identify the WOX1 downstream genes, we performed a microarray analysis of shoot apices of transgenic Arabidopsis thaliana lines harboring 35S::WOX1:glucocorticoid receptor (GR) in which the WOX1 function was temporarily enhanced by dexamethasone (DEX). The effects of transient enhancement of WOX1 function on shoot apices of seedlings were analyzed by using GR-DEX system. Plants were grown on solid medium contains 0.5x Murashige and Skoog (MS) salts, 1% sucrose, 0.05% MES-KOH (w/v) pH 5.7, 1.2 % purified agar for 6 days and transfer to liquid medium containing 0.5x MS salts, 1% sucrose and 0.05% MES-KOH (w/v) pH 5.7 with or without 10 µM DEX, 10 µM cycloheximide (CHX) and 20 µM IAA. Samples were treated with DEX, CHX and IAA treatments for 6 hours, 6 hours and 3 hours, respectively, before collection. RNA samples were extracted from shoot apices, including leaf primordia, of 6-day post sowing seedlings by using Plant RNeasy Mini Kit (QIAGEN). For analysis of 35S::WOX1:GR plants treated with or without DEX and/or CHX, sampling was performed twice in two independent lines. For analysis of 35S::GFP:GR and of a combined application of DEX and IAA, sampling was performed from two independent lines.