ALTERED MERISTEM PROGRAM1 (AMP1) is a member of the M28 family of carboxypeptidases with a pivotal role in cell fate maintenance in the embryo and shoot meristem. A defect in AMP1 function results in suspensor to embryo conversion and a hypertrophic shoot meristem forming ectopic stem cell pools. 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. Double mutants in CYP78A5 and CYP78A7 develop a similar set of cell fate defects. To further assess whether this phenotypic overlap is also depicted in a congruency at the global gene expression level, we analyzed the transcriptomic responses of both genotypes
AMP1 and CYP78A5/7 act through a common pathway to govern cell fate maintenance in Arabidopsis thaliana.
Age, Specimen part
View SamplesBrassinosteroids (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 SamplesThis SuperSeries is composed of the SubSeries listed below.
The Small Molecule Hyperphyllin Enhances Leaf Formation Rate and Mimics Shoot Meristem Integrity Defects Associated with AMP1 Deficiency.
Specimen part, Treatment
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 and 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 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 SamplesMiR-221 overexpression leads to activation of apoptosis, growth arrest and reduced invasivness in PCa cells. Interaction of miR-221 with potential target genes was analyzed by a genome wide expression profiling.. Regulation of selected genes and proteins identified in the gene array analysis was confirmed by Real Time RT-PCR assay (IRF1, IRF2 SOCS3, STAT1), and Western Blotting. In total, 282 genes were upregulated and 64 downregulated based on a more than 2-fold difference to untransfected PC-3 cells. Regulated genes are involved in apoptosis, hemostasis, oxidative stress response, tumorigenesis and inflammation. We confirmed dysregulation of IRF-2 SOCS3, STAT1,IRF9. These results indicate that miR-221 overexpression might lead to activation of the JAK/STAT pathway and downregulation of miR-221 might contribute to tumorigenesis in PCa cells.
Survival in patients with high-risk prostate cancer is predicted by miR-221, which regulates proliferation, apoptosis, and invasion of prostate cancer cells by inhibiting IRF2 and SOCS3.
Cell line
View SamplesHypoxia triggers aggressive cancer growth and contributes to chemotherapy resistance. Novel therapeutic strategies aim at targeting hypoxia activated signaling pathways. Tumor hypoxia not only affects neoplastic tumor cells but also the surrounding stroma cells. Therefore, a novel ex vivo model was established, which allows the study of hypoxia effects in fragments of non-small cell lung cancer (NSCLC) with preserved tumor microenvironment and 3D-structure. Microarray analysis identified 107 significantly regulated genes with at least two-fold expression change in hypoxic compared to normoxic fragments. However, only four genes were significantly regulated in both subtypes, adenocarcinoma and squamous cell carcinoma. The hypoxic regulation of these four genes was verified in an independent set using quantitative PCR.
Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells.
Specimen part, Treatment
View SamplesKRAS mutations are the ost abundand driver mutations found in lung adenocarcinoma patients. Unfortunately, there are no clinical approved inhibitors available, to directly target mutant forms of KRAS. The aim of the study was to unravel the impact of upstream Egfr activation in signaling of mutated K-ras. We found that upregulation of G12D mutant Kras induced genes was significantly impaired when Egfr was knocked out. Our data suggests that signaling of mutant Kras depends on upstream activation. This finding may be exploited therapeutically by targeting EGFR in KRAS mutant patients. Overall design: We isolated mouse alveolar type II cells and induced the Kras G12D mutation, with and without concomitant Egfr knockout, in vitro. Cells lysates were analyzed 5 days following transgene induction.
JAK-STAT inhibition impairs K-RAS-driven lung adenocarcinoma progression.
Specimen part, Cell line, Subject
View SamplesThe genome of Epstein-Barr virus (EBV) encodes 86 proteins but only a limited set is expressed in EBV-growth transformed B cells, termed lymphoblastoid cell lines (LCLs). These cells proliferate via the concerted action of EBV nuclear antigens (EBNAs) and latent membrane proteins (LMPs), some of which are rate limiting to establish a stable homeostasis of growth promoting and anti-apoptotic activities. We show here that EBV mutants, which lack the EBNA-3A gene, are impaired but can still initiate cell-cycle entry and proliferation of primary human B cells in contrast to an EBNA-2-deficient mutant virus. Surprisingly and in contrast to previous reports, these viral mutants are attenuated in growth transformation assays but give rise to permanently growing EBNA-3A negative B cell lines which exhibit reduced proliferation rates and elevated levels of apoptosis. Expression profiles of EBNA-3A deficient LCLs are characterized by 129 upregulated and 167 downregulated genes, which are significantly enriched for genes involved in apoptotic processes or cell cycle progression like the tumor suppressor gene p16/INK4A or might contribute to essential steps in the viral life cycle. In addition EBNA-3A cellular target genes remarkably overlap with previously identified targets of EBNA-2.
Differential gene expression patterns of EBV infected EBNA-3A positive and negative human B lymphocytes.
Specimen part
View Samples10 days old tumor spheroids were processed for RNA isolation using the Quiagen RNeasy Micro Kit and cDNA synthesis was done using the Ambion WT Expression Kit. Wt, HIF-1 k/d and HIF-2 k/d samples were compared to each other.
HIF-2alpha-dependent PAI-1 induction contributes to angiogenesis in hepatocellular carcinoma.
Specimen part, Cell line
View Samples