Redox Responsive Transcription Factor1 (RRTF1) in Arabidopsis is rapidly and transiently upregulated by H202, as well as biotic and abiotic induced redox signals. Inactivation of RRTF1 restricts and overexpression promotes reactive oxygen species (ROS) accumulation in response to stress. Overexpressor (oe) lines are impaired in root and shoot development, light sensitive and susceptible to Alternaria brassicae infection. These symptoms are diminished by the beneficial root endophyte Piriformospora indica which reduces ROS accumulation locally in roots and systemically in shoots, and by antioxidants and ROS inhibitors which scavenge ROS. More than 850 stress-, redox-, ROS regulated-, ROS scavenging-, defense-, cell death- and senescence-related genes are regulated by RRTF1, ~ 30% of them have ROS related functions. Bioinformatic analyses and in vitro DNA binding assays demonstrate that RRTF1 binds to GCC-box and GCC-box like sequences in the promoter of RRTF1-responsive genes. Upregulation of RRTF1 by stress stimuli as well as H2O2 requires WRKY18/40/60. RRTF1 is co-regulated with the phylogenetically related RAP2.6, which contains GCC-box like sequene in its promoter, but RAP2.6 oe lines do not accumulate higher ROS levels. RRTF1 stimulates systemic ROS accumulation in distal non-stressed leaves. We conclude that the highly conserved RRTF1 rapidly, transiently and systemically induce ROS accumulation in response to ROS and ROS-producing abiotic and biotic stress signals. Necrotrophs stimulate RRTF1 expression, while symbiotic interactions of Arabidopsis with (hemi)-biotrophs and P. indica do not affect or repress RRTF1 expression.
High REDOX RESPONSIVE TRANSCRIPTION FACTOR1 Levels Result in Accumulation of Reactive Oxygen Species in Arabidopsis thaliana Shoots and Roots.
Age, Specimen part
View SamplesPiriformospora indica, an endophytic fungus of Sebacinales, colonizes the roots of many plant species including Arabidopsis thaliana. The symbiotic interaction promotes plant per-formance, growth and resistance/tolerance against abiotic and biotic stress. We demonstrate that exudated compounds from the fungus activate stress and defense responses in the Arabidopsis roots and shoots before the two partners are in physical contact. They induce stomata closure, stimulate reactive oxygen species (ROS) production, stress-related phytohormone accumulation and activate defense and stress genes in the roots and/or shoots. Once a physical contact is established, the stomata re-open, ROS and phytohormone levels decline, and the gene expression pattern indicates a shift from defense to mutualistic interaction.
The interaction of Arabidopsis with Piriformospora indica shifts from initial transient stress induced by fungus-released chemical mediators to a mutualistic interaction after physical contact of the two symbionts.
Age, Specimen part
View SamplesProducts derived from roots of Leuzea carthamoides DC. (maral root) are being promoted as anti-aging and adaptogenic. The phytoecdysteroids are considered as active principles with numerous beneficial effects, but little is known about the pharmacological properties of Leuzea extracts. We, therefore, investigated the effects of a lipophilic Leuzea root extract on ER+ breast cancer MCF-7 cells at transcriptional level in comparison to 17beta-estradiol and the ER antagonist tamoxifen. With the extract 241 genes were regulated more than 1.5 fold. We observed gene regulation in an anti-proliferative and pro-apoptotic manner.
Effects of Leuzea carthamoides on human breast adenocarcinoma MCF-7 cells determined by gene expression profiling and functional assays.
No sample metadata fields
View SamplesExtracts from the rhizome of Cimicifuga racemosa (black cohosh) are increasingly popular as herbal alternative to hormone replacement therapy (HRT) for the alleviation of postmenopausal disorders. However, the molecular mode of action and the active principles are presently not clear. Previously published data have been largely contradictory. We, therefore, investigated the effects of a lipophilic Cimicifuga rhizome extract on the ER+ breast cancer MCF-7 cells at transcriptional level in comparision to 17beta-estradiol and the ER antagonist tamoxifen. With the extract 431 genes were regulated more than 1.5 fold. The overall expression pattern differed from those of 17-estradiol or the estrogen receptor antagonist tamoxifen. We observed an enrichment of genes in an anti-proliferative and apoptosis-sensitizing manner, together with an increase of mRNAs coding for gene products involved in several stress response pathways. Regulated genes of these functional groups were highly overrepresented among all regulated genes. Various transcripts coding for oxidoreductases were induced, as for example the cytochrome P450 family members 1A1 and 1B1. In addition, some transcripts associated with antitumor but also tumor-promoting activity were regulated.
Gene expression profiling reveals effects of Cimicifuga racemosa (L.) NUTT. (black cohosh) on the estrogen receptor positive human breast cancer cell line MCF-7.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The transcription factor prospero homeobox protein 1 is a direct target of SoxC proteins during developmental vertebrate neurogenesis.
Specimen part
View SamplesThe HMG-domain containing SoxC transcription factors Sox4 and Sox11 are expressed in the vertebrate central nervous system in neuronal precursors and neuroblasts. They are required during early stages of neurogenesis.
The transcription factor prospero homeobox protein 1 is a direct target of SoxC proteins during developmental vertebrate neurogenesis.
Specimen part
View SamplesThe HMG-domain containing SoxC transcription factors Sox4 and Sox11 are expressed in the vertebrate central nervous system in neuronal precursors and neuroblasts. They are required during early stages of neurogenesis.
The transcription factor prospero homeobox protein 1 is a direct target of SoxC proteins during developmental vertebrate neurogenesis.
Specimen part
View SamplesThe methyl-cytosine binding protein 2 (MeCP2) is a reader of epigenetic DNA methylation marks and necessary and sufficient to reorganize 3D heterochromatin structure during cellular differentiation, e.g., myogenesis. In addition to global expression profile changes, myogenic differentiation is accompanied by 3D-heterochromatin reorganization that is dependent on MeCP2. MeCP2 is enriched at pericentric heterochromatin foci (chromocenters). During myogenesis, the total heterochromatin foci number per nucleus decreases while foci volumes and MeCP2 protein levels increase. Ectopic MeCP2 is able to mimic similar heterochromatin restructuring in the absence of differentiation.
Gene repositioning within the cell nucleus is not random and is determined by its genomic neighborhood.
Specimen part, Cell line
View SamplesAbiotic stress is a major factor for crop productivity, a problem likely to be exacerbated by climate change. Improving the tolerance to environmental stress is one of the most important goals of crop breeding programmes. While the early responses to abiotic stress in plants are well studied, plant adaptation to enduring or recurring stress conditions has received little attention. This project investigates the molecular mechanism of the maintenance of acquired thermotolerance as a model case of stress memory in Arabidopsis. Arabidopsis seedlings acquire thermotolerance through a heat treatment at sublethal temperatures. To investigate the underlying mechanisms, we are investigating changes in the transcriptome at two timepoints after a heat acclimation treatment using Arabidopsis thaliana seedlings.
Arabidopsis miR156 Regulates Tolerance to Recurring Environmental Stress through SPL Transcription Factors.
Treatment
View SamplesTransposable elements (TEs) make up a large proportion of eukaryotic genomes. As their mobilization creates genetic variation that threatens genome integrity, TEs are epigenetically silenced through several pathways and this may spread to neighboring sequences. JUMONJI (JMJ) proteins can function as anti-silencing factors and prevent silencing of genes next to TEs. Whether TE silencing is counterbalanced by the activity of anti-silencing factors is still unclear. Here, we characterize JMJ24 as a regulator of TE silencing. We show that loss of JMJ24 results in increased silencing of the DNA transposon AtMu1c, while overexpression of JMJ24 reduces silencing. JMJ24 has a JumonjiC (JmjC) domain and two RING domains. JMJ24 auto-ubiquitinates in vitro, demonstrating E3 ligase activity of the RING domain(s). JMJ24-JmjC binds the N-terminal tail of histone H3 and full-length JMJ24 binds histone H3 in vivo. JMJ24 activity is anti-correlated with histone H3 lysine 9 dimethylation (H3K9me2) levels at AtMu1c. Double mutant analyses with epigenetic silencing mutants suggest that JMJ24 antagonizes histone H3K9me2, and requires H3K9 methyltransferases for its activity on AtMu1c. Genome-wide transcriptome analysis indicates that JMJ24 affects silencing at additional TEs. Our results suggest that the JmjC domain of JMJ24 has lost demethylase activity but has been retained as a binding domain for histone H3. This is in line with phylogenetic analyses indicating that JMJ24 [with the mutated JmjC domain] is widely conserved in angiosperms. Taken together, this study assigns a role in TE silencing to a conserved JmjC-domain protein with E3 ligase activity, but no demethylase activity.
A JUMONJI Protein with E3 Ligase and Histone H3 Binding Activities Affects Transposon Silencing in Arabidopsis.
No sample metadata fields
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