Maternal 5-HT1A-receptor (R) is required for the timely development of the hippocampus and the establishment of emotional behaviors in Swiss-Webster (SW) mice. A partial and/or complete loss of maternal 5-HT1AR results in delayed ventral dentate granule cell (v-DGC) development and subsequent anxiety-like phenotype in the wild-type offspring by a non-genetic, presumably epigenetic mechanism. Here we tested v-DGCs for genome-wide DNA methylation changes elicited by the receptor deficient maternal environment. We identified a set of hypomethylated regions in the offspring of receptor deficient mothers. A significant fraction of these maternal-differentially methylated regions (m-DMRs) mapped to strong CpG islands, sequences that are typically not methylated or if methylated, resistant to environmental-induced changes. Many m-DMRs mapped to exons and some were associated with expression changes. Their hypomethylation was due to an arrest in de novo methylation and, to a lesser extent, to demethylation during postnatal life indicating that the perturbation in methylation coincides with the developmental delay in DGC maturation in the offspring of receptor deficient mothers. Inhibiting methylation in differentiating neurons impaired their maturation further suggesting a link between de novo methylation and neuronal differentiation. These data suggest that methylation at specific exonic CpG-islands may contribute to the mechanism through which maternal 5-HT1AR modulates hippocampal development and consecutively the level of anxiety in the SW offspring. Reduced 5-HT1AR-binding has been reported in individuals, particularly in association with anxiety/depression, including peri/postpartum depression. Therefore, maternal receptor deficit may contribute, via a non-genetic mechanism, to the high prevalence and heritability of anxiety disorders in human. Overall design: Examined transcriptomes of 5HT1A wild type offspring with 5HT1A wild type/heterozygous mother or 5HT1A KO offspring with 5HT1A of heterozygous/knock out mother
Differential gene body methylation and reduced expression of cell adhesion and neurotransmitter receptor genes in adverse maternal environment.
Specimen part, Cell line, Subject
View SamplesThe traditional view of hematopoiesis has been that all the cells of the peripheral blood are the progeny of a unitary homogeneous pool of hematopoietic stem cells (HSCs). Recent evidence suggests that the hematopoietic system is actually maintained by a consortium of HSC subtypes with distinct functional characteristics. We show here that myeloid-biased HSCs (My-HSCs) and lymphoid-biased (Ly-HSCs) can be purified according to their capacity for Hoechst dye efflux in combination with canonical HSC markers.
Distinct hematopoietic stem cell subtypes are differentially regulated by TGF-beta1.
Sex, Specimen part
View SamplesA systematic survey of the transcriptional status of individual segments of the developing chick hindbrain (r1-5) and the adjacent region of the embryonic midbrain (m) during the HH11 stage of chick development
Transcriptomic analysis of midbrain and individual hindbrain rhombomeres in the chick embryo.
Specimen part
View SamplesCerebral palsy is primarily an upper motor neuron disease that results in a spectrum of progressive movement disorders. Secondary to the neurological lesion, muscles from patients with cerebral palsy are often spastic and form debilitating contractures that limit range of motion and joint function. With no genetic component, the pathology of skeletal muscle in cerebral palsy is a response to aberrant neurological input in ways that are not fully understood. This study was designed to gain further understanding of the skeletal muscle response to cerebral palsy using microarrays and correlating the transcriptional data with functional measures. Hamstring biopsies from gracilis and semitendinosus muscles were obtained from a cohort of patients with cerebral palsy (n=10) and typically developing patients (n=10) undergoing surgery. Affymetrix HG-U133A 2.0 chips (n=40) were used and expression data was verified for 6 transcripts using quantitative real-time PCR, as well as for two genes not on the microarray. Chips were clustered based on their expression and those from patients with cerebral palsy clustered separately. Significant genes were determined conservatively based on the overlap of three summarization algorithms (n=1,398). Significantly altered genes were analyzed for over-representation among gene ontologies, transcription factors, pathways, microRNA and muscle specific networks. These results centered on an increase in extracellular matrix expression in cerebral palsy as well as a decrease in metabolism and ubiquitin ligase activity. The increase in extracellular matrix products was correlated with mechanical measures demonstrating the importance in disability. These data lay a framework for further studies and novel therapies.
Transcriptional abnormalities of hamstring muscle contractures in children with cerebral palsy.
Sex, Age, Disease, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Analysis of Gal4-directed transcription activation using Tra1 mutants selectively defective for interaction with Gal4.
Time
View SamplesWe used microarrays to detail the global program of gene expression underlying gonadotropin-releasing hormone (GnRH) generation and delamination from the olfactory placode.
Serotonin Receptor 1A (HTR1A), a Novel Regulator of GnRH Neuronal Migration in Chick Embryo.
Specimen part
View SamplesPromoter-specific transcriptional activators (activators) stimulate transcription through direct interactions with one or more components of the transcription machinery, termed the target. Previous studies have provided evidence that the Tra1 subunit of the yeast SAGA (Spt-Ada-Gcn5-acetyltransferase) complex is the target of the yeast activator Gal4. However, several other general transcription factors, in particular the mediator complex, have also been implicated as Gal4 targets. To investigate the essentiality of Tra1 as a target of Gal4, here we derive Tra1 mutants that are selectively defective for interaction with Gal4 in vivo (Gal4 Interaction Defective (GID) mutants). In contrast to wild-type Tra1, Tra1 GID mutants are not recruited by Gal4 to the promoter and cannot support Gal4-directed transcription activation, demonstrating that the Gal4Tra1 interaction is required for Gal4 function. In yeast strains expressing a Tra1 GID mutant, Gal4 promoter binding is unexpectedly also diminished indicating that Gal4 and Tra1 bind cooperatively. Consistent with cooperative binding, we demonstrate that the interaction between Gal4 and Tra1 occurs predominantly on the promoter and not off DNA. Finally, we show that although Tra1 is also targeted by other activators, these interaction are unaffected by GID mutations, revealing an unanticipated specificity of the Gal4-Tra1 interaction.
Analysis of Gal4-directed transcription activation using Tra1 mutants selectively defective for interaction with Gal4.
Time
View SamplesPromoter-specific transcriptional activators (activators) stimulate transcription through direct interactions with one or more components of the transcription machinery, termed the target. Previous studies have provided evidence that the Tra1 subunit of the yeast SAGA (Spt-Ada-Gcn5-acetyltransferase) complex is the target of the yeast activator Gal4. However, several other general transcription factors, in particular the mediator complex, have also been implicated as Gal4 targets. To investigate the essentiality of Tra1 as a target of Gal4, here we derive Tra1 mutants that are selectively defective for interaction with Gal4 in vivo (Gal4 Interaction Defective (GID) mutants). In contrast to wild-type Tra1, Tra1 GID mutants are not recruited by Gal4 to the promoter and cannot support Gal4-directed transcription activation, demonstrating that the Gal4Tra1 interaction is required for Gal4 function. In yeast strains expressing a Tra1 GID mutant, Gal4 promoter binding is unexpectedly also diminished indicating that Gal4 and Tra1 bind cooperatively. Consistent with cooperative binding, we demonstrate that the interaction between Gal4 and Tra1 occurs predominantly on the promoter and not off DNA. Finally, we show that although Tra1 is also targeted by other activators, these interaction are unaffected by GID mutations, revealing an unanticipated specificity of the Gal4-Tra1 interaction.
Analysis of Gal4-directed transcription activation using Tra1 mutants selectively defective for interaction with Gal4.
No sample metadata fields
View SamplesSince the first generation of induced Pluripotent Stem cells (iPSCs), several reprogramming systems have been used to study its molecular mechanisms. However, the system of choice largely affects the reprogramming efficiency, influencing our view on the mechanisms. Here we demonstrate that reprogramming triggered by less efficient polycistronic reprogramming cassettes not only highlights Mesenchymal-Epithelial Transition (MET) as a roadblock, but also faces more severe difficulties to attain a pluripotent state even post-MET. Also, in contrast to previous findings, more efficient cassettes can reprogram both wild type and Nanog-/- fibroblasts with comparable efficiencies, routes and kinetics, rebutting previous studies that Nanog is critical for iPSC generation. We revealed that the 9 amino acids in the N-terminus of Klf4 in polycistronic reprogramming cassettes are the dominant factor causing these critical differences. Our data establishes that some reprogramming roadblocks are system-dependent, highlighting the need to pursue mechanistic studies with close attention to the systems to better understand reprogramming. Overall design: The aim of the experiment is to compare the reprogramming pathways driven by two different polycistronic cassettes (MKOS and OKMS). We have isolated cells at intermediate stages of both MKOS and OKMS reprogramming and analysed their gene expression profiles. 2N- are CD44- ICAM1-, Nanog-GFP-, 3N- are CD44- ICAM1+, Nanog-GFP-, 3N+ are CD44- ICAM1+, Nanog-GFP+, all from day 10 of reprogramming. MKOS/OKMS iPSCs are established iPSC clones, TNG an Embryonic Stem Cell line carrying a Nanog-GFP reporter published in Chambers et al. Cell, 113, 643-655, from this line TNG MKOS and OKMS Embryonic Stem Cells were generated after targeting the Sp3 locus with the MKOS or the OKMS cassette respectively,E14 a reference Embryonic Stem Cell line and MEF are Mouse Embryonic Fibroblasts either wild type or generaterd from TNG MKOS or OKMS ESCs. D6 is the D6s4B5 iPSC line published in O''Malley et al. Nature, 499, 88-91.
Reprogramming Roadblocks Are System Dependent.
No sample metadata fields
View SamplesAllergic asthma is a complex trait. Several approaches have been used to identify biomarkers involved in this disease. This study aimed at demonstrating the relevance and validity of microarrays in the definition of allergic asthma expression pattern. The authors compared the transcript expressions of bronchial biopsy of 2 different microarray experiments done 2 years apart, both including nonallergic healthy and allergic asthmatic subjects (n = 4 in each experiment). U95Av2 and U133A GeneChips detected respectively 89 and 40 differentially expressed genes. Fifty-five percent of the U133A genes were previously identified with the U95Av2 arrays. The immune signaling molecules and the proteolytic enzymes were the most preserved categories between the 2 experiments, because 3/4 of the genes identified by the U133A were also significant in the U95Av2 study for both categories. These results demonstrate the relevance of microarray experiments using bronchial tissues in allergic asthma. The comparison of these GeneChip studies suggests that earlier microarray results are as relevant as actual ones to target new genes of interest, particularly in function categories linked to the studied disease. Moreover, it demonstrates that microarrays are a valuable technology to target novel allergic asthma pathways as well as biomarkers.
A comparison of two sets of microarray experiments to define allergic asthma expression pattern.
Specimen part, Disease
View Samples