We identified Ncoa3 as a regulator of neuronal morphology and microRNA activity. In order to uncover target genes of this transcriptional coactivator we performed this microarray analysis.
A large-scale functional screen identifies Nova1 and Ncoa3 as regulators of neuronal miRNA function.
Specimen part, Treatment
View SamplesPhysiologically, Notch signal transduction plays a pivotal role in differentiation; pathologically, Notch signaling contributes to the development of cancer. Transcriptional activation of Notch target genes involves cleavage of the Notch receptor in response to ligand binding, production of the Notch intracellular domain (NICD), and NICD migration into the nucleus and assembly of a coactivator complex. Posttranslational modifications of the NICD are important for its transcriptional activity and protein turnover. Deregulation of Notch signaling and stabilizing mutations of Notch1 have been linked to leukemia development. We found that the methyltransferase CARM1 (coactivator-associated arginine methyltransferase 1; also known as PRMT4) methylated NICD at five conserved arginine residues within the C-terminal transactivation domain. CARM1 physically and functionally interacted with the NICD-coactivator complex and was found at gene enhancers in a Notch-dependent manner. Although a methylation-defective NICD mutant was biochemically more stable, this mutant was biologically less active as measured with Notch assays in embryos of Xenopus laevis and Danio rerio. Mathematical modeling indicated that full but short and transient Notch signaling required methylation of NICD.
Site-specific methylation of Notch1 controls the amplitude and duration of the Notch1 response.
Cell line
View SamplesWe analyzed and classified Whi3-regulated and ploidy-regulated genes in haploid and diploid strains of the Sigma1278b genetic background under vegetative growth conditions.<br></br><br></br>For this purpose, we measured transcriptional profiles of two different haploid MATa and one diploid MATa/a yeast strains of the following genotypes: WHI3 strain (SS_YHUM468=YHUM0468), whi3 strain (SS_ySS137=YHUM1920) and whi3-delta/whi3-delta strain (SS_ySS137dipl=YHUM2152). All three strains were grown in duplicate in YNB medium supplemented with tryptophan and uracil at 30 degrees C to an optical density of 1.0 before extraction of total RNA and transcriptional profiling<br></br><br></br>
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Sex, Subject
View SamplesWe determined and classified Yak1-regulated genes in haploid strains of the Sigma1278b genetic background under vegetative growth conditions. For this purpose, we measured transcriptional profiles of different haploid MATa yeast strains of the following genotypes:YAK1 (468=YHUM0468), yak1 (1313=YHUM1313), strain YHUM1313 (yak1) carrying a high copy plasmid with YAK1 (1313Yhc) and strain YHUM1313 (yak1) carrying a high copy plasmid with YAK1 K398R (1313KDhc). All strains were grown in duplicate in YNB medium supplemented with tryptophan at 30 degrees Celsius to an optical density of 1.0 before extraction of total RNA and transcriptional profiling.
No associated publication
Sex
View SamplesWe determined and classified Whi3-regulated genes in haploid strains of the Sigma1278b genetic background under vegetative growth conditions. For this purpose, we measured transcriptional profiles of two different haploid MATa yeast strains of the following genotypes: WHI3 strain (468=YHUM0468) and whi3 strain (1105=YHUM1105).Both starins were grown in duplicate in YNB medium with tryptophan at 30°C to an optical density of 1.0 before extraction of total RNA and transcriptional profiling
No associated publication
Sex
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.
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View SamplesWe performed a comprehensive molecular and cellular analysis of primary dermal fibroblasts taken from a patient with recurrent cancers, harboring a BRCA1 mosaic epimutation (BRCA1mosMe) in comparison to their isogenic control fibroblasts (BRCA1wt), taken from the patients healthy monozygous sister.
No associated publication
Specimen part, Disease
View SamplesVery small embryonic-like (VSEL) cells have been described as putatively pluripotent stem cells present in murine bone marrow and human umbilical cord blood (hUCB) and as such are of high potential interest for regenerative medicine. However, there remain some questions concerning the precise identity and properties of VSEL cells, particularly those derived from hUCB. For this reason, we have carried out an extensive characterisation of purified populations of VSEL cells from a large number of UCB samples. Consistent with a previous report, we find that VSEL cells are CXCR4+, have a high density, are indeed significantly smaller than HSC and have an extremely high nuclear/cytoplasmic ratio. Their nucleoplasm is unstructured and stains strongly with Hoechst 33342. A comprehensive FACS screen for surface markers characteristic of embryonic, mesenchymal, neuronal or hematopoietic stem cells revealed negligible expression on VSEL cells. These cells failed to expand in vitro under a wide range of culture conditions known to support embryonic or adult stem cell types and a microarray analysis revealed the transcriptional profile of VSELs to be clearly distinct both from well-defined populations of pluripotent and adult stem cells and from the mature hematopoietic lineages. Finally, we detected an aneuploid karyotype in the majority of purified VSEL cells by fluorescence in situ hybridisation. These data support neither an embryonic nor an adult stem cell like phenotype, suggesting rather that hUCB VSEL are an aberrant and inactive population that is not comparable to murine VSEL.
No associated publication
Specimen part
View Samples