scholarly journals Novel regulatory mechanisms for the CFTR gene

2009 ◽  
Vol 37 (4) ◽  
pp. 843-848 ◽  
Author(s):  
Christopher J. Ott ◽  
Neil P. Blackledge ◽  
Shih-Hsing Leir ◽  
Ann Harris

The CFTR (cystic fibrosis transmembrane conductance regulator) gene, which when mutated causes cystic fibrosis, encompasses nearly 200 kb of genomic DNA at chromosome 7q31.2. It is flanked by two genes ASZ1 [ankyrin repeat, SAM (sterile α-motif) and basic leucine zipper] and CTTNBP2 (cortactin-binding protein 2), which have very different expression profiles. CFTR is expressed primarily in specialized epithelial cells, whereas ASZ1 is transcribed exclusively in the testis and ovary, and CTTNBP2 is highly expressed in the brain, kidney and pancreas, with lower levels of expression in other tissues. Despite its highly regulated pattern of expression, the promoter of the CFTR gene apparently lacks the necessary elements to achieve this. We previously suggested that cis-acting regulatory elements elsewhere in the locus, both flanking the gene and within introns, were required to co-ordinate regulated, tissue-specific expression of CFTR. We identified a number of crucial elements, including enhancer-blocking insulators flanking the locus, intronic tissue-specific enhancers and also characterized some of the interacting proteins. We recently employed a high-resolution method of mapping DHS (DNase I-hypersensitive sites) using tiled microarrays. DHS are often associated with regulatory elements and use of this technique generated cell-specific profiles of potential regulatory sequences in primary cells and cell lines. We characterized a set of cis-acting elements within the CFTR locus and demonstrated direct physical interaction between them and the CFTR promoter, by chromosome conformation capture (3C). These results provide the first insight into the three-dimensional structure of the active CFTR gene.

2021 ◽  
Vol 22 (5) ◽  
pp. 2599
Author(s):  
Mégane Collobert ◽  
Ozvan Bocher ◽  
Anaïs Le Nabec ◽  
Emmanuelle Génin ◽  
Claude Férec ◽  
...  

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.


1989 ◽  
Vol 9 (5) ◽  
pp. 2228-2232
Author(s):  
C D Trainor ◽  
J D Engel

Molecular genetic analysis of a number of vertebrate erythroid cell-specific genes has identified at least two types of cis-acting regulatory sequences which control the complex developmental pattern of gene expression during erythroid cell maturation. Tissue-specific cellular enhancers have been identified 3' to three erythroid cell-specific genes, and additional regulatory elements have been identified in the promoters of many erythroid genes. We show that the histone H5 enhancer, like the adult beta-globin enhancer, is involved in mediating the developmental induction of histone H5 mRNA as erythroid cells mature. We also describe the preliminary characterization of a tissue-specific regulatory element within the 5' region of the H5 locus and describe investigations of the interaction between this element and the histone H5 enhancer in mediating histone H5 regulation.


1989 ◽  
Vol 9 (5) ◽  
pp. 2228-2232 ◽  
Author(s):  
C D Trainor ◽  
J D Engel

Molecular genetic analysis of a number of vertebrate erythroid cell-specific genes has identified at least two types of cis-acting regulatory sequences which control the complex developmental pattern of gene expression during erythroid cell maturation. Tissue-specific cellular enhancers have been identified 3' to three erythroid cell-specific genes, and additional regulatory elements have been identified in the promoters of many erythroid genes. We show that the histone H5 enhancer, like the adult beta-globin enhancer, is involved in mediating the developmental induction of histone H5 mRNA as erythroid cells mature. We also describe the preliminary characterization of a tissue-specific regulatory element within the 5' region of the H5 locus and describe investigations of the interaction between this element and the histone H5 enhancer in mediating histone H5 regulation.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5816 ◽  
Author(s):  
Lidong Hao ◽  
Xiuli Qiao

As one of the non-selective cation channel gene families, the cyclic nucleotide-gated channel (CNGC) gene family plays a vital role in plant physiological processes that are related to signal pathways, plant development, and environmental stresses. However, genome-wide identification and analysis of the CNGC gene family in maize has not yet been undertaken. In the present study, twelve ZmCNGC genes were identified in the maize genome, which were unevenly distributed on chromosomes 1, 2, 4, 5, 6, 7, and 8. They were classified into five major groups: Groups I, II, III, IVa, and IVb. Phylogenetic analysis showed that gramineous plant CNGC genes expanded unequally during evolution. Group IV CNGC genes emerged first, whereas Groups I and II appeared later. Prediction analysis of cis-acting regulatory elements showed that 137 putative cis-elements were related to hormone-response, abiotic stress, and organ development. Furthermore, 120 protein pairs were predicted to interact with the 12 ZmCNGC proteins and other maize proteins. The expression profiles of the ZmCNGC genes were expressed in tissue-specific patterns. These results provide important information that will increase our understanding of the CNGC gene family in maize and other plants.


Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 235 ◽  
Author(s):  
Hannah Swahn ◽  
Ann Harris

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.


1987 ◽  
Vol 7 (10) ◽  
pp. 3749-3758
Author(s):  
V da C Soares ◽  
R M Gubits ◽  
P Feigelson ◽  
F Costantini

To investigate the tissue-specific and hormonal regulation of the rat alpha 2u globulin gene family, we introduced one cloned member of the gene family into the mouse germ line and studied its expression in the resulting transgenic mice. Alpha 2u globulingene 207 was microinjected on a 7-kilobase DNA fragment, and four transgenic lines were analyzed. The transgene was expressed at very high levels, specifically in the liver and the preputial gland of adult male mice. The expression in male liver was first detected at puberty, and no expression was detected in female transgenic mice. This pattern of expression is similar to the expression of endogenous alpha 2u globulin genes in the rat but differs from the expression of the homologous mouse major urinary protein (MUP) gene family in that MUPs are synthesized in female liver and not in the male preputial gland. We conclude that these differences between rat alpha 2u globulin and mouse MUP gene expression are due to evolutionary differences in cis-acting regulatory elements. The expression of the alpha 2u globulin transgene in the liver was abolished by castration and fully restored after testosterone replacement. The expression could also be induced in the livers of female mice by treatment with either testosterone or dexamethasone, following ovariectomy and adrenalectomy. Therefore, the cis-acting elements responsible for regulation by these two hormones, as well as those responsible for tissue-specific expression, are closely linked to the alpha 2u globulin gene.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4209-4209
Author(s):  
John A. Stamatoyannopouylos ◽  
Michael Hawrylycz ◽  
Richard Humbert ◽  
James C. Wallace ◽  
Man Yu ◽  
...  

Abstract Cis-acting sequences play defining roles in the control of genes involved in hematopoiesis. However, for the vast majority of such genes, regulatory sequences remain to be defined. We describe a powerful, generic approach to identification of cis-regulatory sequences that may be applied to any gene locus in the context of any cell type. We used densely tiled primers and a novel real-time PCR-based assay to create continuous, high-resolution quantitative profiles of in vivo chromatin structure across entire gene domains. Such profiles can be analyzed using robust statistical algorithms to pinpoint disruptions in chromatin structure that are characteristic of cis-regulatory elements. We analyzed >1Mb of human genomic terrain from diverse gene loci in the context of several hematopoietic cell lines and cleanly delineated a spectrum of classical cis-regulatory activities including enhancers, promoters, insulators, and locus control regions. The approach displayed outstanding sensitivity (100%) and specificity (>99.6%) for known elements and was successful in defining novel elements even in heavily-explored terrain such as the alpha- and beta-globin loci. Since only small quantities of cells are required, the approach can be used readily in the context of hematopoietic progenitors. Systematic application of quantitative chromatin profiling to relevant genes promises to expand dramatically our understanding of the regulation of hematopoiesis.


1987 ◽  
Vol 166 (3) ◽  
pp. 625-636 ◽  
Author(s):  
Y Wang ◽  
A S Larsen ◽  
B M Peterlin

We mapped cis-acting regulatory elements in the HLA-DR alpha gene, which encodes the monomorphic subunit of the HLA-DR heterodimer. Genomic fragments of HLA-DR alpha were placed 5' or 3' to the chloramphenicol acetyltransferase reporter gene, the transcription of which was initiated from the Herpes simplex thymidine kinase promoter. In transient expression assays, fragments from the body of the HLA-DR alpha gene were able to increase chloramphenicol acetyltransferase activity in a position-, orientation-, and promoter-independent yet tissue-specific fashion. These HLA-DR alpha cis-acting regulatory elements contain previously identified DNase I-hypersensitive sites and DNA sequences homologous to those found in other eukaryotic transcriptional enhancers.


Genetics ◽  
1995 ◽  
Vol 140 (4) ◽  
pp. 1389-1406 ◽  
Author(s):  
G I Patterson ◽  
K M Kubo ◽  
T Shroyer ◽  
V L Chandler

Abstract The b gene encodes a transcriptional regulator of the maize anthocyanin biosynthetic pathway. Certain b alleles participate in paramutation, an allele-specific interaction that heritably alters transcription. The moderately transcribed B' allele heritably reduces the transcription of the highly transcribed B-I allele in a B'/B-I heterozygote, such that the B-I allele becomes B'. To identify the cis-acting sequences required for paramutation, we used B' or B-I alleles to isolate intragenic recombinants with B-Peru, an allele that is insensitive to paramutation and has distinct tissue-specific regulation. Physical mapping of the recombinant alleles showed that most of the crossovers were in a small region near the 5' end of the b-transcribed region. Analysis of the recombinant alleles revealed that the ability to cause and respond to paramutation and the control of tissue-specific expression both localize to the 5' region of the gene. The 3' boundary of these functions lies just upstream of the translation initiation codon. The 5' boundary has been estimated to be no more than 0.1 cM further upstream (1-150 kb). Thus, sequences critical for paramutation lie upstream of the b coding sequences and may include transcriptional regulatory sequences.


2014 ◽  
Vol 42 (15) ◽  
pp. 9612-9622 ◽  
Author(s):  
Nehal Gosalia ◽  
Daniel Neems ◽  
Jenny L. Kerschner ◽  
Steven T. Kosak ◽  
Ann Harris

Abstract Higher order chromatin structures across the genome are maintained in part by the architectural proteins CCCTC binding factor (CTCF) and the cohesin complex, which co-localize at many sites across the genome. Here, we examine the role of these proteins in mediating chromatin structure at the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR encompasses nearly 200 kb flanked by CTCF-binding enhancer-blocking insulator elements and is regulated by cell-type-specific intronic enhancers, which loop to the promoter in the active locus. SiRNA-mediated depletion of CTCF or the cohesin component, RAD21, showed that these two factors have distinct roles in regulating the higher order organization of CFTR. CTCF mediates the interactions between CTCF/cohesin binding sites, some of which have enhancer-blocking insulator activity. Cohesin shares this tethering role, but in addition stabilizes interactions between the promoter and cis-acting intronic elements including enhancers, which are also dependent on the forkhead box A1/A2 (FOXA1/A2) transcription factors (TFs). Disruption of the three-dimensional structure of the CFTR gene by depletion of CTCF or RAD21 increases gene expression, which is accompanied by alterations in histone modifications and TF occupancy across the locus, and causes internalization of the gene from the nuclear periphery.


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