Project description:Here, we show through comparative epigenomic analysis the identification of enhancers and promoters that have gained activity in humans during cardiogenesis. These cis-regulatory elements (CREs) are associated with genes involved in heart development and function, and may account for species-specific differences between human and mouse hearts. Supporting these findings, genetic variants that are associated with human cardiac phenotypic/disease traits, particularly those differing between human and mouse, are enriched in human-gained CREs. During early stages of human cardiogenesis, these CREs are also gained within genomic loci of transcriptional regulators, potentially expanding their role in human heart development. In particular, we discovered that gained enhancers in the locus of the early human developmental regulator ZIC3 are selectively accessible within a subpopulation of mesoderm cells which exhibits cardiogenic potential, thus possibly extending the function of ZIC3 beyond its conserved left-right asymmetry role. Genetic deletion of these enhancers identified a human gained enhancer that was required for not only ZIC3 and early cardiac gene expression at the mesoderm stage but also cardiomyocyte differentiation. Overall, our results illuminate how human gained CREs may contribute to human-specific cardiac attributes, and provide insight into how transcriptional regulators may gain developmental roles through the evolutionary acquisition of enhancers.
Project description:The heart, a vital organ which is first to develop, has adapted its size, structure and function in order to accommodate the circulatory demands for a broad range of animals. Although heart development is controlled by a relatively conserved network of transcriptional/chromatin regulators, how the human heart has evolved species-specific features to maintain adequate cardiac output and function remains to be defined. Here, we show through comparative epigenomic analysis the identification of enhancers and promoters that have gained activity in humans during cardiogenesis. These cis-regulatory elements (CREs) are associated with genes involved in heart development and function, and may account for species-specific differences between human and mouse hearts. Supporting these findings, genetic variants that are associated with human cardiac phenotypic/disease traits, particularly those differing between human and mouse, are enriched in human-gained CREs. During early stages of human cardiogenesis, these CREs are also gained within genomic loci of transcriptional regulators, potentially expanding their role in human heart development. In particular, we discovered that gained enhancers in the locus of the early human developmental regulator ZIC3 are selectively accessible within a subpopulation of mesoderm cells which exhibits cardiogenic potential, thus possibly extending the function of ZIC3 beyond its conserved left-right asymmetry role. Genetic deletion of these enhancers identified a human gained enhancer that was required for not only ZIC3 and early cardiac gene expression at the mesoderm stage but also cardiomyocyte differentiation. Overall, our results illuminate how human gained CREs may contribute to human-specific cardiac attributes, and provide insight into how transcriptional regulators may gain developmental roles through the evolutionary acquisition of enhancers.
Project description:Mammalian heart development is built on highly conserved molecular mechanisms with polygenetic perturbations resulting in a spectrum of congenital heart diseases (CHD). However, the transcriptional landscape of cardiogenic ontogeny that regulates proper cardiogenesis remains largely based on candidate-gene approaches. Herein, we designed a time-course transcriptome analysis to investigate the genome-wide expression profile of innate murine cardiogenesis ranging from embryonic stem cells to adult cardiac structures. This comprehensive analysis generated temporal and spatial expression profiles, prioritized stage-specific gene functions, and mapped the dynamic transcriptome of cardiogenesis to curated pathways. Reconciling the bioinformatics of the congenital heart disease interactome, we deconstructed disease-centric regulatory networks encoded within this cardiogenic atlas to reveal stage-specific developmental disturbances clustered on epithelial-to-mesenchymal transition (EMT), BMP regulation, NF-AT signaling, TGFb-dependent induction, and Notch signaling. Therefore, this cardiogenic transcriptional landscape defines the time-dependent expression of cardiac ontogeny and prioritizes regulatory networks at the interface between health and disease. To interrogate the temporal and spatial expression profiles across the entire genome during mammalian heart development, we designed a time-course microarray experiment using the mouse model at defined stages of cardiogenesis, starting with embryonic stem cells (ESC, R1 stem cell line), early embryonic developmental stages: E7.5 whole embryos, E8.5 heart tubes, left and right ventricle tissues at E9.5, E12.5, E14.5, E18.5 to 3 days after birth (D3) and adult heart (Figure 1A). At each time point, microarray experiments were performed on triplicate biological samples. Starting at E9.5, tissue samples from left ventricles (LV) and right ventricles (RV) were microdissected for RNA purification and microarray analysis to determine spatially differential gene expression between LV and RV during heart development.
Project description:Protein phosphorylation is known to regulate a wide scenario of key cellular processes. However, phosphorylation mediated regulatory networks in honeybee embryogenesis are largely unknown. We identified 6342 phosphosites from 2438 phosphoproteins and predicted 168 kinases in the honeybee embryo. The worker and drone develop similar phosphoproteome architectures and central phosphorylation events during embryogenesis.