A 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 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 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 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 SamplesAge-related defects in stem cells can limit proper tissue maintenance and hence contribute to a shortened life-span. Using highly purified hematopoietic stem cells from mice aged 2 to 21 months, we demonstrate a deficit in function yet an increase in stem cell number with advancing age. Expression analysis of more than 14,000 genes identified 1500 that were age-induced and 1600 that were age-repressed. Genes associated with the stress response, inflammation, and protein aggregation dominated the upregulated expression profile, while the downregulated profile was marked by genes involved in the preservation of genomic integrity and chromatin remodeling. Many chromosomal regions showed coordinate loss of transcriptional regulation, and an overall increase in transcriptional activity with aged, and inappropriate expression genes normally regulated by epigenetic mechanisms was observed. Hematopoietic stem cells from early-aging mice expressing a mutant p53 allele reveal that aging of stem cells can be uncoupled from aging at an organismal level. These studies show that HSC are not protected from aging. Instead, loss of epigenetic regulation at the chromatin level may drive both functional attenuation of cells, as well as other manifestations of aging, including the increased propensity for neoplastic transformation.
Aging hematopoietic stem cells decline in function and exhibit epigenetic dysregulation.
No sample metadata fields
View SamplesFew families of signaling factors have been implicated in the control of development. Here we identify the neuropeptides nociceptin and somatostatin, a neurotransmitter and neuroendocrine hormone, as a class of developmental signals in chick and zebrafish. We show that signals from the anterior mesendoderm are required for the formation of anterior placode progenitors with one of the signals being somatostatin. Somatostatin controls ectodermal expression of nociceptin and both peptides regulate Pax6 in lens and olfactory progenitors. Consequently, loss of somatostatin and nociceptin signaling leads to severe reduction of lens formation. Our findings not only uncover these neuropeptides as developmental signals, but also identify a long-sought-after mechanism that initiates Pax6 in placode progenitors and may explain the ancient evolutionary origin of neuropeptides, pre-dating a complex nervous system.
Neuropeptides: developmental signals in placode progenitor formation.
Specimen part
View SamplesPURPOSE: To examine if a parental high fat diet (HFD) influences metabolic health in two generations of offspring, and alters the germ cell (GC) transcriptome. PROCEDURE: GC-eGFP Sprague Dawley rats were weaned onto HFD (45% fat) or Control Diet (CD; 10% fat). After metabolic testing, founders (F0) were bred with controls, establishing the F1 generation. Germ cells from F0 males were isolated and their RNA sequenced. F1 rats were bred with control rats at 17 weeks to generate F2 offspring. FINDINGS: HFD resulted in 9.7% and 14.7% increased weight in male and female F0 respectively. F1 offspring of HFD mothers were heavier than controls. F1 daughters of HFD-fed males were also heavier. F2 male offspring derived from HFD-fed maternal grandfathers were 7.2% heavier, and exhibited increases of 31% in adiposity, 97% in plasma leptin and 300% in luteinising hormone to testosterone ratio. HFD exposure did not alter the F0 GC transcriptome. CONTROLS: Matched CD was consumed by all animals not consuming the HFD. Animals were compared to a parallel cohort of CD rats. CONCLUSIONS: HFD consumption by maternal grandfathers results in a disrupted metabolic phenotype in grandsons. This effect is not mediated by alterations to the GC transcriptome. Overall design: Male rats high fat diet vs. control diet. 4 replicates per condition. SmallRNA seq and mRNAseq for each replicate and condition
High-fat diet disrupts metabolism in two generations of rats in a parent-of-origin specific manner.
No sample metadata fields
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 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
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