Identification of genes cooperatively regulated by cytokinin and HD-ZIP III transcription factors
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ABSTRACT: In Arabidopsis thaliana, cytokinin responsive B-type ARR transcription factors and HD-ZIP III transcription factors such as REVOLUTA (REV), act cooperatively as master regulators of shoot regeneration. To identify the downstream targets of ARR-HD-ZIP III transcriptional complex, we used an inducible line of REV, 35S::FLAG-GR-rREV, in which FLAG-tagged miR165/6-non-targetable form of REV (rREV)-GR fusion protein was expressed from 35S promoter. DEX treatment induced activation of REV by translocation of FLAG-GR-rREV fusion protein from cytoplasm to the nucleus. We treated 35S::FLAG-GR-rREV seedlings with 6-benzylaminopurine (6-BA, a cytokinin), dexamethasone (DEX), or 6-BA+DEX for 2 hours. Total RNAs were extracted and subjected to Agilent Arabidopsis Gene Expression Microarray analyses. The differentially expressed genes (>1.5-fold, p<0.05) were identified. 10-day-old 35S::FLAG-GR-rREV plants were treated with 6-benzylaminopurine (6-BA), dexamethasone (DEX), or 6-BA+DEX for 2 hours. DEX treatment induced activation of REV by translocation of FLAG-GR-rREV fusion protein from cytoplasm to the nucleus. Total RNA was extracted with RNeasy Mini Kit and hybridized to Agilent Arabidopsis Gene Expression Microarray. Differentially expressed genes were defined by a 1.5-fold expression difference with a P value<0.05. Biological replicates were performed.
Project description:In Arabidopsis thaliana, cytokinin responsive B-type ARR transcription factors and HD-ZIP III transcription factors such as REVOLUTA (REV), act cooperatively as master regulators of shoot regeneration. To identify the downstream targets of ARR-HD-ZIP III transcriptional complex, we used an inducible line of REV, 35S::FLAG-GR-rREV, in which FLAG-tagged miR165/6-non-targetable form of REV (rREV)-GR fusion protein was expressed from 35S promoter. DEX treatment induced activation of REV by translocation of FLAG-GR-rREV fusion protein from cytoplasm to the nucleus. We treated 35S::FLAG-GR-rREV seedlings with 6-benzylaminopurine (6-BA, a cytokinin), dexamethasone (DEX), or 6-BA+DEX for 2 hours. Total RNAs were extracted and subjected to Agilent Arabidopsis Gene Expression Microarray analyses. The differentially expressed genes (>1.5-fold, p<0.05) were identified.
Project description:Dexamethasone applied to WT, GR-AS2, GR-KAN1, GR-REV and GR-STM seedlings and expression measured at 0, 30, 60 and 120 minutes after Dex application.
Project description:Downstream genes of PtVNS genes were explored with inducible expression system using glucocorticoid receptor (GR). Transgenic poplar plants expressing 35S:AtVND7-VP16-GR were treated with dexamethazone (DEX). A number of genes related to the formation of xylem vessels were induced by DEX.
Project description:The Arabidopsis thaliana Myb transcription factor, FE, acts as a key regulator of phase transition. In order to identify potential target genes of FE protein, we performed microarray experiments. Using fe-1 and transgenic plants overexpressing GR-tagged FE (35S::FE-GR), we compared transcriptional profiling of WT (L.er) vs fe-1 and Dex-treated 35S::FE-GR vs Mock-treated 35S::FE-GR. Transcriptional profiling of A. thaliana comparing WT (L.er) with the fe-1 mutant
Project description:Downstream genes of PtVNS genes were explored with inducible expression system using glucocorticoid receptor (GR). Transgenic poplar plants expressing 35S:AtVND7-VP16-GR were treated with dexamethazone (DEX). A number of genes related to the formation of xylem vessels were induced by DEX. Total RNAs of the transgenic plants carrying 35S:AtVND7-VP16-GR treated with and without DEX were compared.
Project description:A glucocorticoid-regulated BBM protein (35S:BBM-GR) was used in combination with microarray analysis to identify genes directly activated by BBM. We employed the system described by (Lloyd et al., 1994) in which dexamethasone (DEX) and cycloheximide (CHX) are applied together to respectively, induce nuclear localization of the BBM-GR protein and prevent translation of the primary targets mRNAs. In this way it is possible to identify direct targets of a transcriptional activator by comparing gene expression profiles between DEX+CHX-treated transgenic and wild-type tissues. The ability of the 35S:BBM GR construct to induce somatic embryogenesis in Arabidopsis seedlings was determined by phenotypic observation of 35S:BBM GR seeds germinated and grown in the presence of 10 µM dexamethasone (DEX). As in 35S:BBM seedlings, we observed somatic embryo formation on the cotyledons, first leaves and shoot meristem of DEX-treated 35S:BBM GR seedlings. We identified a set of 20 genes (including BBM itself) and our analysis indicates that BBM directly activates a signaling pathway comprising transcription factors and other signaling molecules, but which does not initially include genes known to induce somatic embryogenesis, such as LEC1, LEC2 or WUS. The functions of the BBM target genes are unknown, however a number of them have recently been identified in microarray screens for meristem-expressed genes. The identification of BBM-interacting partners and downstream targets provides new tools for unraveling pathways related to plant cell growth and organogenesis. Keywords: transcriptional activation
Project description:To obtain information on which genes are regulated by an Arabidopsis transcription factor Dof3.2, we treated Arabidopsis transgenic 35S::Dof3.2-GR seedlings with dexamethasone (DEX), then performed DNA microarray analyses. T3 homozygous Dof3.2-GR transgenic line was used.
Project description:This experiment describes gene expression after the activation of APETALA1-GR, to study and identify AP1 target genes. We used a 35S:AP1-GR ap1 cal line to induce a synchronized response activating the AP1-GR fusion protein in ap1 cal inflorescence-like meristems through dexamethasone or dexamethasone+cycloheximide treatment. Tissue samples were collected at 3hrs after the treatment. The expression profiles of the individual samples were then analyzed by gene expression profiling using whole-genome oligonucleotide arrays (Agilent, custom-commercial). We treated inflorescences of 35S:AP1-GR ap1-1 cal-1 plants with a dexamethasone-containing or a mock solution, or with identical solutions that contained in addition 10 M-NM-<M cycloheximide. Tissue was collected 3 hours after the treatment. Samples from each of the four biological replicates resulted in a set of four hybridization pairs: Mock vs. Dex, Mock vs. Chx, Mock vs. Dex+Chx, and Chx vs. Dex+Chx. Dye polarities were switched between biological replicates.