Project description:Although most disease-causing variants are within coding region of genes, it is now well established that cis-acting regulatory sequences, depending on 3D-chromatin organization, are required for temporal and spatial control of gene expression. Disruptions of such regulatory elements and/or chromatin conformation are likely to play a critical role in human genetic disease. Hence, recurrent monoallelic cases of the most common hereditary type of nonsyndromic hearing loss (i.e. DFNB1) carrying out only one identified pathogenic allele, led to strongly suggest the presence of uncharacterized distal cis-acting elements in the missing allele. Herewith, we study the spatial organization of a large DFNB1 locus encompassing the gap junction protein beta 2 (GJB2) gene, the most frequently mutated gene in this inherited hearing loss, with the chromosome conformation capture carbon copy technology (5C). By combining this approach with functional activity reporter assays and mapping of CCCTC-binding factor (CTCF) along the DFNB1 locus by quantitative real-time PCR chromatin immunoprecipitation, we identify a novel set of cooperating GJB2 cis-acting elements and propose a DFNB1 three-dimensional looping regulation model. A loop chromatin forming, allows bringing closer enhancers to the GJB2 promoter, but also avoids GJB2 silencing with an enhancer-blocking insulator activity.
Project description:Higher order chromatin structure establishes domains that organize the genome and coordinate gene expression. However, the molecular mechanisms controlling transcription of individual loci within a topological domain (TAD) are not fully understood. The cystic fibrosis transmembrane conductance regulator (CFTR) gene provides a paradigm for investigating these mechanisms. CFTR occupies a TAD bordered by CTCF/cohesin binding sites within which are cell-type-selective cis-regulatory elements for the locus. We showed previously that intronic and extragenic enhancers, when occupied by specific transcription factors, are recruited to the CFTR promoter by a looping mechanism to drive gene expression. Here we use a combination of CRISPR/Cas9 editing of cis-regulatory elements and siRNA-mediated depletion of architectural proteins to determine the relative contribution of structural elements and enhancers to the higher order structure and expression of the CFTR locus. We found the boundaries of the CFTR TAD are conserved among diverse cell types and are dependent on CTCF and cohesin complex. Removal of an upstream CTCF-binding insulator alters the interaction profile, but has little effect on CFTR expression. Within the TAD, intronic enhancers recruit cell-type selective transcription factors and deletion of a pivotal enhancer element dramatically decreases CFTR expression, but has minor effect on its 3D structure. Examination of open chromatin region in Caco2 (colorectal adenocarcinoma cells), HBE (primary human bronchial epithelial cells), and primary adult human epididymis cells
Project description:We investigated the transcriptional activation and cis-regulatory elements of effector ISGs in CD8+ murine dendritic cells (DCs) stimulated with IFN-beta. We analysed gene repression changes and characterized activated cis-regulatory regions. Binding of ISGF3 subunits (IRF9, Stat1, and Stat2) and other transcription factors, DNA motifs, and chromatin status were also determined.
Project description:We have combined the 4C chromosome conformation capture protocol with high throughput, genome-wide sequence analysis to characterise in full a cis-acting regulatory network at a single locus. In contrast to methods which identify large interacting regions (10-1000kb), the 4C approach provides a comprehensive, high resolution analysis of a specific locus with the aim of defining, in detail, all cis- regulatory elements controlling a single gene or gene cluster. Using the human M-NM-1-globin locus as a model we detected all known local and long-range interactions with this gene cluster. In addition we identified two interactions with genes located 300 kb (NME4) and 625 kb (FAM173a) from the M-NM-1-globin cluster. Using paired-end sequencing it was possible for the first time to identify interactions between specific subsets of cis-regulatory elements in populations of cells and within individual cells. Two biological replicates of 4C amplification from the promoters of the human HBA gene promoters. Sequenced as paired end fragments usinig Illumina GAII
Project description:We have combined the 4C chromosome conformation capture protocol with high throughput, genome-wide sequence analysis to characterise in full a cis-acting regulatory network at a single locus. In contrast to methods which identify large interacting regions (10-1000kb), the 4C approach provides a comprehensive, high resolution analysis of a specific locus with the aim of defining, in detail, all cis- regulatory elements controlling a single gene or gene cluster. Using the human M-NM-1-globin locus as a model we detected all known local and long-range interactions with this gene cluster. In addition we identified two interactions with genes located 300 kb (NME4) and 625 kb (FAM173a) from the M-NM-1-globin cluster. Using paired-end sequencing it was possible for the first time to identify interactions between specific subsets of cis-regulatory elements in populations of cells and within individual cells. Two biological replicates of 4C amplification from the promoters of the human HBA and HBB genes and B-Cell controls. Quality of B-cell material was confirmed using amplification from a CTCF bound region associated with Human Axin Gene.