Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Meyerowitz Lab Arabidopsis Operon Array v4 - 4200A scanner - AP1-GR ap1cal inflorescences - time series (hours)

ABSTRACT: 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 treatment. Tissue samples were collected immediately after the treatment, as well as subsequent timepoints. The expression profiles of the individual samples were then analyzed by gene expression profiling using whole-genome oligonucleotide arrays (non-commercial; Meyerowitz Lab Arabidopsis Operon Array v4). Keywords: time course Four sets of biologically independent tissue samples were collect at 0, 2, 4 ,8, and 12 hours after the application of dexamethasone (Dex-; activation of the AP1-GR fusion protein) or a mock solution (Mock-; control). In each of the biological replicates of the time course experiments, all the samples derived from dexamethasone (Dex)-treated plants were labeled with one dye (i.e., Cy3), and all the samples derived from the corresponding Mock-treated plants were labeled with the alternative dye (i.e., Cy5). The dyes used for labeling RNA from a given treatment type (Dex and Mock) were switched for two of the replicate experiments, to reduce dye-related artifacts. Dex- and Mock-derived samples for each timepoint and biological replicate were co-hybridized. This experimental setup resulted in a total of 5 hybridizations per set (0h, 2h, 4, 8h, and 12h; Dex vs. Mock at each timepoint), and two biological replicate sets labeled with each dye polarity (Mock-Cy3/Dex-Cy5, and vice versa). The combined ratio data results are available as a supplementary file on the Series record.

ORGANISM(S): Arabidopsis thaliana

SUBMITTER: Jose Riechmann

PROVIDER: E-GEOD-20182 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Orchestration of floral initiation by APETALA1.

Kaufmann Kerstin K Wellmer Frank F Muiño Jose M JM Ferrier Thilia T Wuest Samuel E SE Kumar Vijaya V Serrano-Mislata Antonio A Madueño Francisco F Krajewski Pawel P Meyerowitz Elliot M EM Angenent Gerco C GC Riechmann José Luis JL

Science (New York, N.Y.) 20100401 5974

The MADS-domain transcription factor APETALA1 (AP1) is a key regulator of Arabidopsis flower development. To understand the molecular mechanisms underlying AP1 function, we identified its target genes during floral initiation using a combination of gene expression profiling and genome-wide binding studies. Many of its targets encode transcriptional regulators, including known floral repressors. The latter genes are down-regulated by AP1, suggesting that it initiates floral development by abrogat ...[more]

PMID: 20360106

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Project description:Cell-cell communication is critical for stem cell maintenance. Shoot apical meristem (SAM) located at the shoot tip harbors stem cells within the central zone (CZ). Their progeny differentiate in the adjacent peripheral zone (PZ). WUSCHEL (WUS) is a homeodomain transcription factor produced in a few cells of the organizing center (OC), located beneath the CZ. It has been shown to specify stem cell fate and also activate CLAVATA3 (CLV3) expression in cells of the CZ. CLV3 is a secreted peptide that activates a membrane bound receptor kinase-CLAVATA1 to restrict WUS transcription to the OC. It has been hypothesized that WUS activates CLV3 expression and stem cell fate in adjacent cells of the CZ by activating a non-cell autonomous signal. Contrary to this hypothesis, here we show that the WUS protein after being synthesized in cells of the OC, migrates into the superficial cell layers of the CZ where it activates CLV3 transcription by binding to its promoter elements. WUS also migrates laterally into the PZ to repress the expression of differentiation promoting transcription factors by binding to their regulatory regions. Migration of a stem cell inducing transcription factor into adjacent cells to activate a negative regulator, whereby restricting its own accumulation is unique to plant stem cell niches. While stem cell promoting transcription factor directly repressing differentiation promoting transcription factors to prevent premature differentiation of stem cell progenitors is conserved among diverse stem cell niches. A dexamethasone inducible version of WUSCHEL was used to identify its direct tragets. To analyze WUS-regulated gene expression programs at a higher spatial resolution, we introduced a dexamethasone (Dex)-inducible form of WUS consisting of the WUS protein-coding region fused to sequences coding for the ligand-binding domain of the rat glucocorticoid receptor (GR), expressed under a ubiquitous promoter (35S::WUS-GR) into apetala1-1;cauliflower1-1 (ap1-1;cal1-1) double mutant background. 35S::WUS-GR; ap1-1;cal1-1 SAMs were either treated with 10μM Dex or mock solution for four hours and RNA samples were hybridized to Arabidopsis ATH1 gene Chip (Affymmetrix). To identify putative genes that are directly regulated by WUS, in independent experiments, SAMs were simultaneously treated with 10μM Dex and 10μM Cycloheximide (Cyc), protein synthesis inhibitor and Cyc alone for four hours. A comparison of Dex-treated samples with mock identified 641 genes as differentially expressed [DEGs] (≥/≤2 fold; p < 0.01) and comparison of Dex+Cyc with Cyc identified 457 genes as DEGs (≥/≤2 fold; p < 0.01).

Dataset Information

Meyerowitz Lab Arabidopsis Operon Array v4 - 4200A scanner - AP1-GR ap1cal inflorescences - time series (hours)

Publications

Orchestration of floral initiation by APETALA1.

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