Gene expression in zebrafish following knockdown of pitx2 or tbx5
Ontology highlight
ABSTRACT: Key regulators of septum formation between the left and right ventricle in mammals, including the transcription factors TXB5 and PITX2, feature loss-of-function phenotypes that affect development of the two-chambered zebrafish heart, suggesting uncharacterized primordial functions of these septation regulators prior to the evolution of any physical boundaries between heart chambers. Data is as published in Mosimann & Panakova et al (Nature Communications, 2015) Samples for tbx5a versus pitx2ab MO comparison were collected from three independent experiments of MO-injected siblings and uninjected wildtype controls at 56hpf by morphology.
Project description:drl expression initiates during gastrulation and condenses as a band of cells at the prospective lateral embryo margin. In late epiboly, drl:EGFP is detectable as a band of scattered EGFP-fluorescent cells; after gastrulation, drl:EGFP-positive cells coalesce at the embryo margin that then in somitogenesis break down into the anterior and posterior lateral plate with subsequent cell migrations that form the posterior vascular/hematopoietic stripes and the anterior cardiovascular and myeloid precursors. Data is as published in Mosimann & Panakova et al (Nature Communications, 2015) The same pool of homozygous drl:EGFP transgenic zebrafish were mass-mated 3 times and embryos collected at 2ss. Embryos were de-chorionated, homogenized, and sorted, then subject to mRNA isolation and expression analysis.
Project description:Key regulators of septum formation between the left and right ventricle in mammals, including the transcription factors TXB5 and PITX2, feature loss-of-function phenotypes that affect development of the two-chambered zebrafish heart, suggesting uncharacterized primordial functions of these septation regulators prior to the evolution of any physical boundaries between heart chambers. Data is as published in Mosimann & Panakova et al (Nature Communications, 2015)
Project description:Background—YAP, the nuclear effector of Hippo signaling, regulates cellular growth and survival in multiple organs, including the heart, by interacting with TEAD sequence specific DNA-binding proteins. Recent studies showed that YAP stimulates cardiomyocyte proliferation and survival. However, the direct transcriptional targets through which YAP exerts its effects are poorly defined. Methods and Results—To identify genes directly regulated by YAP in cardiomyocytes, we combined differential gene expression analysis in YAP gain- and loss-of-function with genome-wide identification of YAP bound loci using chromatin immunoprecipitation and high throughput sequencing. This screen identified Pik3cb, encoding p110β, a catalytic subunit of phosphoinositol-3-kinase (PI3K), as a candidate YAP effector that promotes cardiomyocyte proliferation and survival. We validated YAP and TEAD occupancy of a conserved enhancer within the first intron of Pik3cb, and show that this enhancer drives YAP-dependent reporter gene expression. Yap gain- and loss-of-function studies indicated that YAP is necessary and sufficient to activate the PI3K-Akt pathway. Like Yap, Pik3cb gain-of-function stimulated cardiomyocyte proliferation, and Pik3cb knockdown dampened the YAP mitogenic activity. Reciprocally, Yap loss-of-function impaired heart function and reduced cardiomyocyte proliferation and survival, all of which were significantly rescued by AAV-mediated Pik3cb expression. Conclusion—Pik3cb is a crucial direct target of YAP, through which the YAP activates PI3K-AKT pathway and regulates cardiomyocyte proliferation and survival. Yap wild type ChIPseq and input
Project description:Zebrafish embryos are significantly more resistant to cyanide exposure at 24 h post fertilization than at 7 days post fertilization. In this experiment we examined the transcriptional response to cyanide exposure at both ages.
Project description:Primary mitochondrial respiratory chain (RC) diseases are heterogeneous in etiology and manifestations but collectively impair cellular energy metabolism. To identify a common cellular response to RC disease, systems biology level transcriptome investigations were performed in human RC disease skeletal muscle and fibroblasts. Global transcriptional and post-transcriptional dysregulation in a tissue-specific fashion was identified across diverse RC complex and genetic etiologies. RC disease muscle was characterized by decreased transcription of cytosolic ribosomal proteins to reduce energy-intensive anabolic processes, increased transcription of mitochondrial ribosomal proteins, shortened 5'-UTRs to improve translational efficiency, and stabilization of 3'-UTRs containing AU-rich elements. These same modifications in a reversed direction typified RC disease fibroblasts. RC disease also dysregulated transcriptional networks related to basic nutrient-sensing signaling pathways, which collectively mediate many aspects of tissue-specific cellular responses to primary RC disease. These findings support the utility of a systems biology approach to improve mechanistic understanding of mitochondrial RC disease. To identify a common cellular response to primary RC that might improve mechanistic understanding and lead to targeted therapies for human RC disease, we performed collective transcriptome profiling in skeletal muscle biopsy specimens and fibroblast cell lines (FCLs) of a diverse cohort of human mitochondrial disease subjects relative to controls. Systems biology investigations of common cellular responses to primary RC disease revealed a collective pattern of transcriptional, post-transcriptional and translational dysregulation occurring in a highly tissue-specific fashion. Affymetrix Human Exon 1.0ST microarray analysis was performed on 29 skeletal muscle samples and Fibroblast cell lines from mitochondrial disease patients and age- and gender-matched controls.
Project description:Many pathways regulating blood formation have been elucidated, yet how each coordinates with embryonic biophysiology to modulate the spatio-temporal production of hematopoietic stem cells (HSCs) is currently unresolved. Here, we report that glucose metabolism impacts the onset and magnitude of HSC induction in vivo. In zebrafish, transient elevations in physiological glucose levels elicited dose-dependent effects on HSC development, including enhanced runx1 expression and hematopoietic cluster formation in the Aorta-Gonad-Mesonephros (AGM) region; embryonic-to-adult transplantation studies confirmed glucose increased functional HSCs. Glucose uptake was required to mediate the enhancement in HSC development; likewise, metabolic inhibitors diminished nascent HSC production and reversed glucose-mediated effects on HSCs. Increased glucose metabolism preferentially impacted hematopoietic and vascular targets, as determined by gene expression analysis, through mitochondrial-derived reactive oxygen species (ROS)-mediated stimulation of hypoxia inducible factor 1α (hif1α); epistasis assays demonstrated hif1α regulates HSC formation in vivo and mediates the dose-dependent effects of glucose metabolism on the timing and magnitude of HSC production. We propose this fundamental metabolic-sensing mechanism enables the embryo to respond to changes in environmental energy input and adjust hematopoietic output to maintain embryonic growth and ensure viability. We performed microarray analysis to explore the changes in gene expression that occur in repsonse to altered metabolism during the induction of developmental hematopoeisis. We compared RNA from zebrafish raised in a solution of 1% glucose from 12-36hpf vs controls. Two biological replicates for each condition were performed.
Project description:Cardiac rhythm is extremely robust, generating 2 billion contraction cycles during the average human life span. Transcriptional control of cardiac rhythm is poorly understood. We found that removal of the transcription factor gene Tbx5 from the adult mouse caused primary spontaneous and sustained atrial fibrillation (AF). Atrial cardiomyocytes from the Tbx5-mutant mice exhibited action potential abnormalities, including spontaneous depolarizations, which were rescued by chelating free calcium. We identified a multitiered transcriptional network that linked seven previously defined AF risk loci: TBX5 directly activated PITX2, and TBX5 and PITX2 antagonistically regulated membrane effector genes Scn5a, Gja1, Ryr2, Dsp, and Atp2a2 In addition, reduced Tbx5 dose by adult-specific haploinsufficiency caused decreased target gene expression, myocardial automaticity, and AF inducibility, which were all rescued by Pitx2 haploinsufficiency in mice. These results defined a transcriptional architecture for atrial rhythm control organized as an incoherent feed-forward loop, driven by TBX5 and modulated by PITX2. TBX5/PITX2 interplay provides tight control of atrial rhythm effector gene expression, and perturbation of the co-regulated network caused AF susceptibility. This work provides a model for the molecular mechanisms underpinning the genetic implication of multiple AF genome-wide association studies loci and will contribute to future efforts to stratify patients for AF risk by genotype.
Project description:We used a smooth muscle cell-specific mineralocorticoid receptor knockout mouse to generate young and aged MR-intact and SMC-MR-KO aortic miRNA to examine the effect of age on vascular miRNA alterations in the presence and absence of SMC-MR. For more information about the mouse model see: McCurley, A et al. Direct regulation of blood pressure by smooth muscle cell mineralocorticoid receptors. Nat Med. 2012 Sep;18(9):1429-33 Total miRNA was extracted from young (3-4 mo) and aged male (12mo) MR-intact and SMC-MR-KO mice to investigate aging-induced alterations in vascular miRNA expression
Project description:To better understand the natural history of bone marrow failure syndromes, we analyzed 124 single nucleotide polymorphism arrays (SNP-A) from a comprehensively characterized cohort of 91 patients who had SNP-A for clinical evaluation of BMFS. 67 samples from 51 patients were genotyped with the Quad610, and 57 samples from 54 patients were genotyped with the Omni1-Quad. This submission includes 55 samples from 54 patients that were genotyped with Omni1-Quad. Illumina Infinium SNP-A genotyping was performed on DNA extracted from bone marrow aspirates using standard manufacturer's protocol