Project description:Genetic mapping studies on crops suggest that agronomic traits can be controlled by loci within the gene-distal intergenic space. Despite the biological importance and the potential agronomic utility of these intergenic loci, they remain virtually uncharacterized in all crop species to date. Here, we provide genetic, epigenomic, and functional molecular evidence supporting the widespread existence of gene-distal (hereafter, distal) loci which act as long-range transcriptional cis-regulatory elements (CREs) in the maize genome. Such loci are enriched for euchromatic chromatin features that suggest their regulatory functions. Chromatin loops link together putative CREs with genes and recapitulate eQTL-gene interactions. Additionally, putative CREs display elevated transcriptional enhancer activities, as measured by STARR-seq. These results provide functional support for the widespread existence of CREs which act over large genomic distances to modulate gene expression.
Project description:Modification of cis regulatory elements to produce differences in gene expression level, localization, and timing is an important mechanism by which organisms evolve divergent adaptations. To examine gene regulatory change during the domestication of maize from its wild progenitor, teosinte, we assessed allele-specific expression in a collection of maize and teosinte inbreds and their F1 hybrids using three tissues from different developmental stages. Our use of F1 hybrids represents the first study in a domesticated crop and wild progenitor that dissects cis and trans regulatory effects to examine characteristics of genes under various cis and trans regulatory regimes. We find evidence for consistent cis regulatory divergence that differentiates maize from teosinte in approximately 4% of genes. These genes are significantly correlated with genes under selection during domestication and crop improvement, suggesting an important role for cis regulatory elements in maize evolution.
Project description:Modification of cis regulatory elements to produce differences in gene expression level, localization, and timing is an important mechanism by which organisms evolve divergent adaptations. To examine gene regulatory change during the domestication of maize from its wild progenitor, teosinte, we assessed allele-specific expression in a collection of maize and teosinte inbreds and their F1 hybrids using three tissues from different developmental stages. Our use of F1 hybrids represents the first study in a domesticated crop and wild progenitor that dissects cis and trans regulatory effects to examine characteristics of genes under various cis and trans regulatory regimes. We find evidence for consistent cis regulatory divergence that differentiates maize from teosinte in approximately 4% of genes. These genes are significantly correlated with genes under selection during domestication and crop improvement, suggesting an important role for cis regulatory elements in maize evolution. We assayed genome-wide cis and trans regulatory differences between maize and its wild progenitor, teosinte, using deep RNA sequencing in F1 hybrid and parent inbred lines for three tissue types (ear, leaf and stem) followed by assessment of allele-specific gene expression.
Project description:Tau is encoded by MAPT and abnormal aggregates of tau are a hallmark of a group of neurodegenerative diseases called tauopathies. MAPT is lowly expressed in neural progenitor cells (NPCs), but it is more highly expressed in oligodendrocytes, astrocytes, and neurons that derive from NPCs. This expression switch at differentiation suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to these differentiated cell types, including neurons.
Project description:Tau is encoded by MAPT and abnormal aggregates of tau are a hallmark of a group of neurodegenerative diseases called tauopathies. MAPT is lowly expressed in neural progenitor cells (NPCs), but it is more highly expressed in oligodendrocytes, astrocytes, and neurons that derive from NPCs. This expression switch at differentiation suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to these differentiated cell types, including neurons.
Project description:Cis-regulatory elements (CREs) are commonly recognized by correlative chromatin features, yet the molecular composition of the vast majority of CREs in chromatin remains unknown. Here we describe a CRISPR affinity purification in situ of regulatory elements (CAPTURE) approach to unbiasedly identify locus-specific chromatin-regulating protein complexes and long-range DNA interactions. Using an in vivo biotinylated endonuclease-deficient Cas9 protein and sequence-specific guide RNAs, we show high-resolution and selective isolation of chromatin interactions at a single copy genomic locus. Purification of human telomeres using CAPTURE identifies known and new telomeric factors. In situ capture of individual constituents of the enhancer cluster controlling human β-globin genes establishes evidence for composition-based hierarchical organization of enhancer structure. Furthermore, unbiased analysis of chromatin interactions at disease-associated cis-elements and developmentally controlled super-enhancers reveals spatial features causally regulate gene transcription. Thus, comprehensive analysis of locus-specific regulatory composition provides mechanistic insight into genome structure and function in development and disease.
Project description:Tau is encoded by MAPT and abnormal aggregates of tau are a hallmark of a group of neurodegenerative diseases called tauopathies. MAPT is lowly expressed in neural progenitor cells (NPCs), but it is more highly expressed in oligodendrocytes, astrocytes, and neurons that derive from NPCs. This expression switch at differentiation suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to these differentiated cell types, including neurons.
Project description:Tau is encoded by MAPT and abnormal aggregates of tau are a hallmark of a group of neurodegenerative diseases called tauopathies. MAPT is lowly expressed in neural progenitor cells (NPCs), but it is more highly expressed in oligodendrocytes, astrocytes, and neurons that derive from NPCs. This expression switch at differentiation suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to these differentiated cell types, including neurons.
Project description:Tau is encoded by MAPT and abnormal aggregates of tau are a hallmark of a group of neurodegenerative diseases called tauopathies. MAPT is lowly expressed in neural progenitor cells (NPCs), but it is more highly expressed in oligodendrocytes, astrocytes, and neurons that derive from NPCs. This expression switch at differentiation suggests that MAPT expression is controlled by transcription factors and cis-regulatory elements specific to these differentiated cell types, including neurons.