Brassinosteroids (BRs) are growth-promoting plant hormones that play a role in abiotic stress responses, but molecular modes that enable this activity remain largely unknown. Here we show that BRs participate in the regulation of freezing tolerance. BR signaling-defective mutants of Arabidopsis thaliana were hypersensitive to freezing before and after cold acclimation. The constitutive activation of BR signaling, in contrast, enhanced freezing resistance. Evidence is provided that the BR-controlled basic helixloophelix transcription factor CESTA (CES) can contribute to the constitutive expression of the C-REPEAT/DEHYDRATION-RESPONSIVE ELEMENT BINDING FACTOR (CBF) transcriptional regulators that control cold responsive (COR) gene expression. In addition, CBF-independent classes of BR-regulated COR genes are identified that are regulated in a BR- and CES-dependent manner during cold acclimation. A model is presented in which BRs govern different cold-responsive transcriptional cascades through the posttranslational modification of CES and redundantly acting factors. This contributes to the basal resistance against freezing stress, but also to the further improvement of this resistance through cold acclimation.
Brassinosteroids participate in the control of basal and acquired freezing tolerance of plants.
Age, Specimen part, Treatment
View SamplesCirculating progesterone (P4) levels decline before the onset of parturition in most animals, but not in humans. This has led to the suggestion that there is functional withdrawal of P4 action at the myometrial level prior to labor onset. Mifepristone is widely used to induce human labour
The study of progesterone action in human myometrial explants.
Specimen part, Disease
View SamplesTF1a AML cell line was selected for in vitro modelling of dormancy in AML. TF1-a were subjected to AML-niche-mimicking in vitro conditioning by culture with TGFB1 and the mTOR inhibitor rapamycin. Also TF1a cells were in vitro cultured with prolonged sublethal doses of Etoposide.
A molecular signature of dormancy in CD34<sup>+</sup>CD38<sup>-</sup> acute myeloid leukaemia cells.
Specimen part
View SamplesALTERED MERISTEM PROGRAM1 (AMP1) is a member of the M28 family of carboxypeptidases with a pivotal role in plant development and stress adaptation. Its most prominent mutant defect is a unique hypertrophic shoot phenotype combining a strongly increased organ formation rate with enhanced meristem size and the formation of ectopic meristem poles. However, so far the role of AMP1 in shoot development could not be assigned to a specific molecular pathway nor is its biochemical function resolved. We used a chemical genetic approach to identify the drug hyperphyllin (HP), which specifically mimics the shoot defects of amp1, including plastochron reduction and enlargement and multiplication of the shoot meristem. To further assess whether hyperphyllin acts in an AMP1-dependent manner we compared the transcriptonal responses of hyperphyllin-treated wild-type Arabidopsis seedlings with those of untreated amp1 mutant seedlings.
The Small Molecule Hyperphyllin Enhances Leaf Formation Rate and Mimics Shoot Meristem Integrity Defects Associated with AMP1 Deficiency.
Specimen part, Treatment
View SamplesGene expression profiling of the inferior and superior wall of the distal midgestation arterial domain (outflow tract) of the wild type CD1 mouse embryonic heart
Tbx1 coordinates addition of posterior second heart field progenitor cells to the arterial and venous poles of the heart.
Specimen part
View SamplesIkaros hypomorphic mice (IkL/L) show plasmacytoid dendritic cell (pDC) defects with an absence of pDCs in the peripheral organs and a reduction of pDCs in the bone marrow (BM). Moreover in vitro differentiation of pDC from IkL/L total BM cells is also defective.
Ikaros cooperates with Notch activation and antagonizes TGFβ signaling to promote pDC development.
Treatment
View SamplesWe compared the seedling transcription profiles to determine the effects of loss-of-function of the BRX gene of Arabidopsis. BRX is required for optimal root growth. We compared seedlings of a loss-of-function line (brx) with its control background (Sav-0). Because the loss-of-function line was derived from introgression, a brx line that was complemented by a transgenic wild type copy of BRX was also included as a control. This line (rescued brx) allows the identification of expression differences that are due to introgression drag. See Mouchel et al. 2004, Genes & Dev. Vol. 18, p. 700 for a detailed description. We also compared to response of the different genotypes to the application of the phytohormones brassinolide (BL) and indole acetic acid (IAA)
BRX mediates feedback between brassinosteroid levels and auxin signalling in root growth.
None
Age, Compound, Time
View SamplesTo assess the importance of the Wnt pathway during T cell develoment, we generated a mouse line (R26-cat) in which high levels of active -catenin are maintained throughout T cell development. Young R26-cat mice (6-week-old) show a differentiation block at the CD4+CD8+ DP stage. All R26-cat mice develop T cell leukemias with a DP phenotype at 5-6 months of age.
β-Catenin activation synergizes with Pten loss and Myc overexpression in Notch-independent T-ALL.
Age, Specimen part
View SamplesThe SAGA co-activator has been implicated in the regulation of a smal subset of genes in budding yeast in transcriptomic analyses performed in steady-state levels of RNA.
SAGA Is a General Cofactor for RNA Polymerase II Transcription.
No sample metadata fields
View SamplesRNA Pol II transcription has been implied to be either regulated by the general transcription factor TFIID or the co-activator SAGA. Also, this dominancy of either SAGA or TFIID might be according to the existance, or not, of a TATA consensus sequence.
Transcription of Nearly All Yeast RNA Polymerase II-Transcribed Genes Is Dependent on Transcription Factor TFIID.
Treatment
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