Transcriptional profiles between mp mutant seedlings and transgenics carrying the dexamethasone-inducible GR-bdl protein

In order to identify targets of the transcription factor AUXIN RESPONSE FACTOR5 / MONOPTEROS (ARF5/MP), we compared transcriptomes of mp-B4149 mutant seedlings (9 day-old) and seedlings carrying the dexamethasone-inducible version of the MP inhibitor protein BODENLOS (GR-bdl). Without dexamethasone (DEX) treatment, this line is identical to the wild-type, while DEX treatment leads to strong inhibition of ARF-dependent transcription. To remove all endogenous MP-inhibiting Aux/IAA proteins, we treated mp or GR-bdl seedlings during 1 hour with auxin (50 micromolar Indole-3-Acetic Acid), either with or without a pretreatment with 10 micromolar DEX for 1 hour. Genes that are activated by MP are expected to br downregulated in mp seedlings and in the GR-bdl line afer DEX treatment. We used biological duplicates for each of the three treatments.