scholarly journals Cell-Selective Regulation of CFTR Gene Expression: Relevance to Gene Editing Therapeutics

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 235 ◽  
Author(s):  
Hannah Swahn ◽  
Ann Harris
Keyword(s):  
Gene Expression ◽  
Cystic Fibrosis ◽  
Gene Editing ◽  
Genetic Diseases ◽  
3D Structure ◽  
Three Dimensional ◽  
Cell Types ◽  
Regulatory Elements ◽  
Cftr Gene ◽  
Specific Expression

The cystic fibrosis transmembrane conductance regulator (CFTR) gene is an attractive target for gene editing approaches, which may yield novel therapeutic approaches for genetic diseases such as cystic fibrosis (CF). However, for gene editing to be effective, aspects of the three-dimensional (3D) structure and cis-regulatory elements governing the dynamic expression of CFTR need to be considered. In this review, we focus on the higher order chromatin organization required for normal CFTR locus function, together with the complex mechanisms controlling expression of the gene in different cell types impaired by CF pathology. Across all cells, the CFTR locus is organized into an invariant topologically associated domain (TAD) established by the architectural proteins CCCTC-binding factor (CTCF) and cohesin complex. Additional insulator elements within the TAD also recruit these factors. Although the CFTR promoter is required for basal levels of expression, cis-regulatory elements (CREs) in intergenic and intronic regions are crucial for cell-specific and temporal coordination of CFTR transcription. These CREs are recruited to the promoter through chromatin looping mechanisms and enhance cell-type-specific expression. These features of the CFTR locus should be considered when designing gene-editing approaches, since failure to recognize their importance may disrupt gene expression and reduce the efficacy of therapies.

scholarly journals CFTR Cooperative Cis-Regulatory Elements in Intestinal Cells

2021 ◽  
Vol 22 (5) ◽  
pp. 2599
Author(s):  
Mégane Collobert ◽  
Ozvan Bocher ◽  
Anaïs Le Nabec ◽  
Emmanuelle Génin ◽  
Claude Férec ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cystic Fibrosis ◽  
Gene Regulation ◽  
Genetic Diseases ◽  
Regulatory Elements ◽  
Cftr Gene ◽  
Intestinal Cells ◽  
Cooperative Effects ◽  
Cis Acting ◽  
Study Techniques

About 8% of the human genome is covered with candidate cis-regulatory elements (cCREs). Disruptions of CREs, described as “cis-ruptions” have been identified as being involved in various genetic diseases. Thanks to the development of chromatin conformation study techniques, several long-range cystic fibrosis transmembrane conductance regulator (CFTR) regulatory elements were identified, but the regulatory mechanisms of the CFTR gene have yet to be fully elucidated. The aim of this work is to improve our knowledge of the CFTR gene regulation, and to identity factors that could impact the CFTR gene expression, and potentially account for the variability of the clinical presentation of cystic fibrosis as well as CFTR-related disorders. Here, we apply the robust GWAS3D score to determine which of the CFTR introns could be involved in gene regulation. This approach highlights four particular CFTR introns of interest. Using reporter gene constructs in intestinal cells, we show that two new introns display strong cooperative effects in intestinal cells. Chromatin immunoprecipitation analyses further demonstrate fixation of transcription factors network. These results provide new insights into our understanding of the CFTR gene regulation and allow us to suggest a 3D CFTR locus structure in intestinal cells. A better understand of regulation mechanisms of the CFTR gene could elucidate cases of patients where the phenotype is not yet explained by the genotype. This would thus help in better diagnosis and therefore better management. These cis-acting regions may be a therapeutic challenge that could lead to the development of specific molecules capable of modulating gene expression in the future.

scholarly journals Chromatin three-dimensional interactions mediate genetic effects on gene expression

Science ◽  
2019 ◽  
Vol 364 (6439) ◽  
pp. eaat8266 ◽  
Author(s):  
O. Delaneau ◽  
M. Zazhytska ◽  
C. Borel ◽  
G. Giannuzzi ◽  
G. Rey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Regulatory Networks ◽  
Three Dimensional ◽  
Cell Types ◽  
Regulatory Elements ◽  
Genetic Effects ◽  
Chromatin Organization ◽  
Regulatory Domains ◽  
Regulatory Variants ◽  
Cis And Trans

Studying the genetic basis of gene expression and chromatin organization is key to characterizing the effect of genetic variability on the function and structure of the human genome. Here we unravel how genetic variation perturbs gene regulation using a dataset combining activity of regulatory elements, gene expression, and genetic variants across 317 individuals and two cell types. We show that variability in regulatory activity is structured at the intra- and interchromosomal levels within 12,583 cis-regulatory domains and 30 trans-regulatory hubs that highly reflect the local (that is, topologically associating domains) and global (that is, open and closed chromatin compartments) nuclear chromatin organization. These structures delimit cell type–specific regulatory networks that control gene expression and coexpression and mediate the genetic effects of cis- and trans-acting regulatory variants on genes.

scholarly journals Deciphering programs of transcriptional regulation by combined deconvolution of multiple omics layers

2017 ◽  
Author(s):  
Daniel Hüebschmann ◽  
Nils Kurzawa ◽  
Sebastian Steinhauser ◽  
Philipp Rentzsch ◽  
Stephen Krämer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Developmental Stages ◽  
Cell Types ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Cell Type ◽  
Specific Expression ◽  
Input Size ◽  
Human Blood Cells ◽  
Cell Type Specific Expression

AbstractMetazoans are crucially dependent on multiple layers of gene regulatory mechanisms which allow them to control gene expression across developmental stages, tissues and cell types. Multiple recent research consortia have aimed to generate comprehensive datasets to profile the activity of these cell type- and condition-specific regulatory landscapes across many different cell lines and primary cells. However, extraction of genes or regulatory elements specific to certain entities from these datasets remains challenging. We here propose a novel method based on non-negative matrix factorization for disentangling and associating huge multi-assay datasets including chromatin accessibility and gene expression data. Taking advantage of implementations of NMF algorithms in the GPU CUDA environment full datasets composed of tens of thousands of genes as well as hundreds of samples can be processed without the need for prior feature selection to reduce the input size. Applying this framework to multiple layers of genomic data derived from human blood cells we unravel mechanisms of regulation of cell type-specific expression in T-cells and monocytes.

Abstract 331: Genome-wide Analysis of Cardiac and Cardiac Fibroblasts Regulatory Elements Reveals Combinatorial Control of Gene Expression

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Tal Golan Lagziel ◽  
Lilac Caspi ◽  
Yair Lewis ◽  
Izhak Kehat
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Target Genes ◽  
Cardiac Fibroblasts ◽  
Cell Types ◽  
Regulatory Elements ◽  
Open Chromatin ◽  
Specific Expression ◽  
Control Of Gene Expression ◽  
Tissue Specific

The mammalian body contains several hundred cell types that share the same genome, but can express distinct gene signatures. This specification of gene expression is achieved through the activity of cis-regulatory genomic elements (CRE), such as enhancers, promoters, and silencers. The Assay for Transposase-Accessible Chromatin followed by sequencing (ATAC-seq) can identify nucleosome evicted open chromatin, an established marker of regulatory regions. Using a differential ATAC-seq approach, coupled with RNA-seq, H3K27ac ChiP-seq, and computational transcription factor (TFs) binding analysis we comprehensively mapped cell-type and condition specific cis regulatory elements for cardiac fibroblasts and cardiomyocytes, and outlined the TFs that control them. We show that in cardiomyocytes six main transcription factor groups, that control their own and each other’s expression, cooperatively bind discrete distal enhancers that are located at a variable distance from the transcription start site of their target genes. None of these factors is entirely tissue specific in expression, yet various combination of binding sites for these factors, densely clustered within a nucleosome length of genomic stretch make these CREs tissue specific. Multiple tissue specific CREs in turn, are clustered around highly tissue specific genes, and multiple factors, acting from the same and from different CREs can converge on these genes to control their tissue specific expression. Together our data puts forward a mechanistic multi-level combinatorial model for cardiac specific genes expression

scholarly journals The CD11b promoter directs high-level expression of reporter genes in macrophages in transgenic mice [published erratum appears in Blood 1995 Apr 1;85(7):1983]

Blood ◽  
1995 ◽  
Vol 85 (2) ◽  
pp. 319-329 ◽  
Author(s):  
S Dziennis ◽  
RA Van Etten ◽  
HL Pahl ◽  
DL Morris ◽  
TL Rothstein ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Transgene Expression ◽  
Heterologous Gene Expression ◽  
Myeloid Cells ◽  
Reporter Genes ◽  
Regulatory Elements ◽  
Specific Expression ◽  
High Level

Abstract CD11b is the alpha chain of the Mac-1 integrin and is preferentially expressed in myeloid cells (neutrophils, monocytes, and macrophages). We have previously shown that the CD11b promoter directs cell-type- specific expression in myeloid lines using transient transfection assays. To confirm that these promoter sequences contain the proper regulatory elements for correct myeloid expression of CD11b in vivo, we have used the -1.7-kb human CD11b promoter to direct reporter gene expression in transgenic mice. Stable founder lines were generated with two different reporter genes, a Thy 1.1 surface marker and the Escherichia coli lacZ (beta-galactosidase) gene. Analysis of founders generated with each reporter demonstrated that the CD11b promoter was capable of driving high levels of transgene expression in murine macrophages for the lifetime of the animals. Similar to the endogenous gene, transgene expression was preferentially found in mature monocytes, macrophages, and neutrophils and not in myeloid precursors. These experiments indicate that the -1.7 CD11b promoter contains the regulatory elements sufficient for high-level macrophage expression. This promoter should be useful for targeting heterologous gene expression to mature myeloid cells.

scholarly journals A gain-of-function single nucleotide variant creates a new promoter which acts as an orientation-dependent enhancer-blocker

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yavor K. Bozhilov ◽  
Damien J. Downes ◽  
Jelena Telenius ◽  
A. Marieke Oudelaar ◽  
Emmanuel N. Olivier ◽  
...  
Keyword(s):  
Gene Expression ◽  
Genetic Diseases ◽  
Regulatory Elements ◽  
Base Change ◽  
Dependent Manner ◽  
Globin Genes ◽  
Single Nucleotide Variants ◽  
Single Nucleotide ◽  
Super Enhancer ◽  
Single Base Change

AbstractMany single nucleotide variants (SNVs) associated with human traits and genetic diseases are thought to alter the activity of existing regulatory elements. Some SNVs may also create entirely new regulatory elements which change gene expression, but the mechanism by which they do so is largely unknown. Here we show that a single base change in an otherwise unremarkable region of the human α-globin cluster creates an entirely new promoter and an associated unidirectional transcript. This SNV downregulates α-globin expression causing α-thalassaemia. Of note, the new promoter lying between the α-globin genes and their associated super-enhancer disrupts their interaction in an orientation-dependent manner. Together these observations show how both the order and orientation of the fundamental elements of the genome determine patterns of gene expression and support the concept that active genes may act to disrupt enhancer-promoter interactions in mammals as in Drosophila. Finally, these findings should prompt others to fully evaluate SNVs lying outside of known regulatory elements as causing changes in gene expression by creating new regulatory elements.

scholarly journals The transcriptional tissue specificity of the human proα1(I) collagen gene is determined by a negative cis-regulatory element in the promoter

1992 ◽  
Vol 286 (1) ◽  
pp. 179-185 ◽  
Author(s):  
C P Simkevich ◽  
J P Thompson ◽  
H Poppleton ◽  
R Raghow
Keyword(s):  
Tissue Specificity ◽  
Regulatory Element ◽  
Mesenchymal Cell ◽  
Cell Types ◽  
Regulatory Elements ◽  
Negative Influence ◽  
Collagen Gene ◽  
Specific Expression ◽  
Cis Acting ◽  
First Intron

The transcriptional activity of plasmid pCOL-KT, in which human pro alpha 1 (I) collagen gene upstream sequences up to -804 and most of the first intron (+474 to +1440) drive expression of the chloramphenicol acetyltransferase (CAT) gene [Thompson, Simkevich, Holness, Kang & Raghow (1991) J. Biol. Chem. 266, 2549-2556], was tested in a number of mesenchymal and non-mesenchymal cells. We observed that pCOL-KT was readily expressed in fibroblasts of human (IMR-90 and HFL-1), murine (NIH 3T3) and avian (SL-29) origin and in a human rhabdomyosarcoma cell line (A204), but failed to be expressed in human erythroleukaemia (K562) and rat pheochromocytoma (PC12) cells, indicating that the regulatory elements required for appropriate tissue-specific expression of the human pro alpha 1 (I) collagen gene were present in pCOL-KT. To delineate the nature of cis-acting sequences which determine the tissue specificity of pro alpha 1 (I) collagen gene expression, functional consequences of deletions in the promoter and first intron of pCOL-KT were tested in various cell types by transient expression assays. Cis elements in the promoter-proximal and intronic sequences displayed either a positive or a negative influence depending on the cell type. Thus deletion of fragments using EcoRV (nt -625 to -442 deleted), XbaI (-804 to -331) or SstII (+670 to +1440) resulted in 2-10-fold decreased expression in A204 and HFL-1 cells. The negative influences of deletions in the promoter-proximal sequences was apparently considerably relieved by deleting sequences in the first intron, and the constructs containing the EcoRV/SstII or XbaI/SstII double deletions were expressed to a much greater extent than either of the single deletion constructs. In contrast, the XbaI* deletion (nt -804 to -609), either alone or in combination with the intronic deletion, resulted in very high expression in all cells regardless of their collagen phenotype; the XbaI*/(-SstII) construct, which contained the intronic SstII fragment (+670 to +1440) in the reverse orientation, was not expressed in either mesenchymal or nonmesenchymal cells. Based on these results, we conclude that orientation-dependent interactions between negatively acting 5′-upstream sequences and the first intron determine the mesenchymal cell specificity of human pro alpha 1 (I) collagen gene transcription.

scholarly journals Characterization of Wild-Type and ΔF508 Cystic Fibrosis Transmembrane Regulator in Human Respiratory Epithelia

2005 ◽  
Vol 16 (5) ◽  
pp. 2154-2167 ◽  
Author(s):  
Silvia M. Kreda ◽  
Marcus Mall ◽  
April Mengos ◽  
Lori Rochelle ◽  
James Yankaskas ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Normal Subjects ◽  
Cell Types ◽  
Cystic Fibrosis Transmembrane Regulator ◽  
Ciliated Cells ◽  
Metabolic Fate ◽  
Specific Expression ◽  
Δf508 Cftr ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

Previous studies in native tissues have produced conflicting data on the localization and metabolic fate of WT and ΔF508 cystic fibrosis transmembrane regulator (CFTR) in the lung. Combining immunocytochemical and biochemical studies utilizing new high-affinity CFTR mAbs with ion transport assays, we examined both 1) the cell type and region specific expression of CFTR in normal airways and 2) the metabolic fate of ΔF508 CFTR and associated ERM proteins in the cystic fibrosis lung. Studies of lungs from a large number of normal subjects revealed that WT CFTR protein localized to the apical membrane of ciliated cells within the superficial epithelium and gland ducts. In contrast, other cell types in the superficial, gland acinar, and alveolar epithelia expressed little WT CFTR protein. No ΔF508 CFTR mature protein or function could be detected in airway specimens freshly excised from a large number of ΔF508 homozygous subjects, despite an intact ERM complex. In sum, our data demonstrate that WT CFTR is predominantly expressed in ciliated cells, and ΔF508 CFTR pathogenesis in native tissues, like heterologous cells, reflects loss of normal protein processing.

Gene-regulatory elements may change the amount, timing, or location of gene expression, cis-Regulation therapy platforms might become a gene therapy to treat many genetic diseases

2021 ◽  
Author(s):  
Moataz Dowaidar
Keyword(s):  
Gene Expression ◽  
Genetic Diseases ◽  
Regulatory Elements ◽  
Tissue Type ◽  
Gene Promoters ◽  
Expression Levels ◽  
Cis Regulation ◽  
Gene Regulatory Elements ◽  
Gene Regulatory ◽  
Gene Expression Levels

Changes in gene expression levels above or below a particular threshold may have a dramatic impact on phenotypes, leading to a wide spectrum of human illnesses. Gene-regulatory elements, also known as cis-regulatory elements (CREs), may change the amount, timing, or location (cell/tissue type) of gene expression, whereas mutations in a gene's coding sequence may result in lower or higher gene expression levels resulting in protein loss or gain. Loss-of-function mutations in both genes produce recessive human illness, while haploinsufficient mutations in 65 genes are also known to be deleterious due to function gain, according to the ClinVar1 and ClinGen3 databases. CREs are promoters living near to a gene's transcription start site and switching it on at predefined times, places, and levels. Other distal CREs, like enhancers and silencers, are temporal and tissue-specific control promoters. Enhancers activate promoters, commonly referred to as "promoters," whereas silencers turn them off. Insulators also restrict promiscuous interactions between enhancers and gene promoters. Systematic genomic approaches can help understand the cis-regulatory circuitry of gene expression by highly detecting and functionally defining these CREs. This includes the new use of CRISPR–CRISPR-associated protein 9 (CRISPR–Cas9) and other editing approaches to discover CREs. Cis-Regulation therapy (CRT) provides many promises to heal human ailments. CRT may be used to upregulate or downregulate disease-causing genes due to lower or higher levels of expression, and it may also be used to precisely adjust the expression of genes that assist in alleviating disease features. CRT may employ proteins that generate epigenetic modifications like methylation, histone modification, or gene expression regulation looping. Weighing CRT's advantages and downsides against alternative treatment methods is crucial. CRT platforms might become a practical technique to treat many genetic diseases that now lack treatment alternatives if academics, patient communities, clinicians, regulators and industry work together.

scholarly journals A scalable platform for the development of cell-type-specific viral drivers

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Sinisa Hrvatin ◽  
Christopher P Tzeng ◽  
M Aurel Nagy ◽  
Hume Stroud ◽  
Charalampia Koutsioumpa ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heterologous Gene Expression ◽  
High Specificity ◽  
Cell Types ◽  
Regulatory Elements ◽  
Cell Type ◽  
Cell Type Specificity ◽  
Cell Type Specific ◽  
The Many ◽  
Dna Regulatory Elements

Enhancers are the primary DNA regulatory elements that confer cell type specificity of gene expression. Recent studies characterizing individual enhancers have revealed their potential to direct heterologous gene expression in a highly cell-type-specific manner. However, it has not yet been possible to systematically identify and test the function of enhancers for each of the many cell types in an organism. We have developed PESCA, a scalable and generalizable method that leverages ATAC- and single-cell RNA-sequencing protocols, to characterize cell-type-specific enhancers that should enable genetic access and perturbation of gene function across mammalian cell types. Focusing on the highly heterogeneous mammalian cerebral cortex, we apply PESCA to find enhancers and generate viral reagents capable of accessing and manipulating a subset of somatostatin-expressing cortical interneurons with high specificity. This study demonstrates the utility of this platform for developing new cell-type-specific viral reagents, with significant implications for both basic and translational research.

Sign in / Sign up

Export Citation Format

Share Document