scholarly journals CGGBP1 regulates CTCF occupancy at repeats

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Divyesh Patel ◽  
Manthan Patel ◽  
Subhamoy Datta ◽  
Umashankar Singh

Abstract Background CGGBP1 is a repeat-binding protein with diverse functions in the regulation of gene expression, cytosine methylation, repeat silencing and genomic integrity. CGGBP1 has also been identified as a cooperator of histone-modifying enzymes and as a component of CTCF-containing complexes that regulate the enhancer–promoter looping. CGGBP1–CTCF cross talk in chromatin regulation has been hitherto unknown. Results Here, we report that the occupancy of CTCF at repeats depends on CGGBP1. Using ChIP-sequencing for CTCF, we describe its occupancy at repetitive DNA. Our results show that endogenous level of CGGBP1 ensures CTCF occupancy preferentially on repeats over canonical CTCF motifs. By combining CTCF ChIP-sequencing results with ChIP sequencing for three different kinds of histone modifications (H3K4me3, H3K9me3 and H3K27me3), we show that the CGGBP1-dependent repeat-rich CTCF-binding sites regulate histone marks in flanking regions. Conclusion CGGBP1 affects the pattern of CTCF occupancy. Our results posit CGGBP1 as a regulator of CTCF and its binding sites in interspersed repeats.

2019 ◽  
Author(s):  
Divyesh Patel ◽  
Manthan Patel ◽  
Umashankar Singh

ABSTRACTCGGBP1 is a repeat-binding protein with diverse functions in regulation of gene expression, cytosine methylation, repeat silencing and genomic integrity. CGGBP1 has also been identified as a cooperator factor in histone modifying complexes and as a component of protein complexes that form the enhancer-promoter loops. Here we report that the occupancy of CTCF at repeats and the chromatin barrier function of these repeat sequences depends on CGGBP1. Using ChIP-sequencing for CTC we describe CTCF binding on repetitive DNA. Our results show that CGGBP1 determines the CTCF occupancy preference for repeats over canonical CTCF-motif. By combining CTCF ChIP-sequencing results with ChIP-sequencing for three different kinds of histone modifications (H3K4me3, H3K9me3 and H3K27me3) we uncover insulator-like chromatin barrier activities of the repeat-rich CTCF-binding sites. This work shows that CGGBP1 is a regulator of CTCF occupancy and posits it as a regulator of barrier functions of CTCF-binding sites.


2020 ◽  
Author(s):  
Manthan Patel ◽  
Divyesh Patel ◽  
Subhamoy Datta ◽  
Umashankar Singh

ABSTRACTThe human CGGBP1 is implicated in a variety of cellular functions. It regulates genomic integrity, cell cycle, gene expression and cellular response to growth signals. Evidence suggests that these functions of CGGBP1 manifest through binding to GC-rich regions in the genome and regulation of interspersed repeats. Recent works show that CGGBP1 is needed for cytosine methylation homeostasis and genome-wide occupancy patterns of the epigenome regulator protein CTCF. It has remained unknown if cytosine methylation regulation and CTCF occupancy regulation by CGGBP1 are independent or interdependent processes. By sequencing immunoprecipitated methylated DNA, we have found that some transcription factor-binding sites resist stochastic changes in cytosine methylation. Of these, we have analyzed the CTCF-binding sites thoroughly and show that cytosine methylation regulation at CTCF-binding DNA sequence motifs by CGGBP1 is deterministic. These CTCF-binding sites are positioned at locations where the spread of cytosine methylation in cis depends on the levels of CGGBP1. Our findings suggest that CTCF occupancy and functions are determined by CGGBP1-regulated cytosine methylation patterns.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Martin Wegner ◽  
Valentina Diehl ◽  
Verena Bittl ◽  
Rahel de Bruyn ◽  
Svenja Wiechmann ◽  
...  

Current technologies used to generate CRISPR/Cas gene perturbation reagents are labor intense and require multiple ligation and cloning steps. Furthermore, increasing gRNA sequence diversity negatively affects gRNA distribution, leading to libraries of heterogeneous quality. Here, we present a rapid and cloning-free mutagenesis technology that can efficiently generate covalently-closed-circular-synthesized (3Cs) CRISPR/Cas gRNA reagents and that uncouples sequence diversity from sequence distribution. We demonstrate the fidelity and performance of 3Cs reagents by tailored targeting of all human deubiquitinating enzymes (DUBs) and identify their essentiality for cell fitness. To explore high-content screening, we aimed to generate the largest up-to-date gRNA library that can be used to interrogate the coding and noncoding human genome and simultaneously to identify genes, predicted promoter flanking regions, transcription factors and CTCF binding sites that are linked to doxorubicin resistance. Our 3Cs technology enables fast and robust generation of bias-free gene perturbation libraries with yet unmatched diversities and should be considered an alternative to established technologies.


2021 ◽  
Author(s):  
Joshua W. Collins ◽  
Daniel Martin ◽  
Shaohe Wang ◽  
Kenneth M. Yamada ◽  

ABSTRACTThe vast majority of mammalian genomes are transcribed as non-coding RNA in what is referred to as “pervasive transcription.” Recent studies have uncovered various families of non-coding RNA transcribed upstream of transcription start sites. In particular, highly unstable promoter upstream transcripts known as PROMPTs have been shown to be targeted for exosomal degradation by the nuclear exosome targeting complex (NEXT) consisting of the RNA helicase MTR4, the zinc-knuckle scaffold ZCCHC8, and the RNA binding protein RBM7. Here, we report that in addition to its known RNA substrates, ZCCHC8 is required for the targeted degradation of pervasive transcripts produced at CTCF binding sites, open chromatin regions, promoters, promoter flanking regions, and transcription factor binding sites. Additionally, we report that a significant number of RIKEN cDNAs and predicted genes display the hallmarks of PROMPTs and are also substrates for ZCCHC8 and/or NEXT complex regulation suggesting these are unlikely to be functional genes. Our results suggest that ZCCHC8 and/or the NEXT complex may play a larger role in the global regulation of pervasive transcription than previously reported.


2018 ◽  
Vol 16 (01) ◽  
pp. 1750029 ◽  
Author(s):  
Vladimir Y. Ovchinnikov ◽  
Denis V. Antonets ◽  
Lyudmila F. Gulyaeva

MicroRNAs (miRNAs) play important roles in the regulation of gene expression at the post-transcriptional level. Many exogenous compounds or xenobiotics may affect microRNA expression. It is a well-established fact that xenobiotics with planar structure like TCDD, benzo(a)pyrene (BP) can bind aryl hydrocarbon receptor (AhR) followed by its nuclear translocation and transcriptional activation of target genes. Another chemically diverse group of xenobiotics including phenobarbital, DDT, can activate the nuclear receptor CAR and in some cases estrogen receptors ESR1 and ESR2. We hypothesized that such chemicals can affect miRNA expression through the activation of AHR, CAR, and ESRs. To prove this statement, we used in silico methods to find DRE, PBEM, ERE potential binding sites for these receptors, respectively. We have predicted AhR, CAR, and ESRs binding sites in 224 rat, 201 mouse, and 232 human promoters of miRNA-coding genes. In addition, we have identified a number of miRNAs with predicted AhR, CAR, and ESRs binding sites that are known as oncogenes and as tumor suppressors. Our results, obtained in silico, open a new strategy for ongoing experimental studies and will contribute to further investigation of epigenetic mechanisms of carcinogenesis.


Development ◽  
1996 ◽  
Vol 122 (5) ◽  
pp. 1373-1383 ◽  
Author(s):  
S. Christensen ◽  
V. Kodoyianni ◽  
M. Bosenberg ◽  
L. Friedman ◽  
J. Kimble

The homologous receptors LIN-12 and GLP-1 mediate diverse cell-signaling events during development of the nematode Caenorhabditis elegans. These two receptors appear to be functionally interchangeable and have sequence similarity to Drosophila Notch. Here we focus on a molecular analysis of the lag-1 gene (lin-12 -and glp-1), which plays a central role in LIN-12 and GLP-1-mediated signal transduction. We find that the predicted LAG-1 protein is homologous to two DNA-binding proteins: human C Promoter Binding Factor (CBF1) and Drosophila Suppressor of Hairless (Su(H)). Furthermore, we show that LAG-1 binds specifically to the DNA sequence RTGGGAA, previously identified as a CBF-1/Su(H)-binding site. Finally, we report that the 5′ flanking regions and first introns of the lin-12, glp-1 and lag-1 genes are enriched for potential LAG-1-binding sites. We propose that LAG-1 is a transcriptional regulator that serves as a primary link between the LIN-12 and GLP-1 receptors and downstream target genes in C. elegans. In addition, we propose that LAG-1 may be a key component of a positive feedback loop that amplifies activity of the LIN-12/GLP-1 pathway.


Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Brian J Morris ◽  
Timothy A Donlon ◽  
Randi Chen ◽  
Kamal H Masaki ◽  
Richard C Allsopp ◽  
...  

The transcription factor FoxO3 regulates multiple genes involved in cell resilience. We have previously implicated variation in non-coding DNA of the FoxO3 gene ( FOXO3 ) with lower blood pressure, reduced inflammation, less hypertension, reduced coronary heart disease mortality, and longevity. The aim of the present study was to determine transcriptional, genetic and genomic mechanisms involving FOXO3 . By DNA sequencing of chromosome 6q21 in lymphoblastoid cell lines of 95 men who had survived to ≥ 95 years of age we identified 110 FOXO3 single nucleotide polymorphisms (SNPs). Thirteen SNPs were at binding sites for 18 transcription factors. Those SNPs appeared to be in physical contact, via RNA polymerase II binding chromatin looping, with sites in the FOXO3 promoter, and likely function together as a cis -regulatory unit. At the chromosome level, FOXO3 was located at the center of a 7.3 Mb 46-gene chromatin domain flanked by gene deserts. We identified distant contact points between FOXO3 and these 46 neighboring genes, through long-range physical contacts via CCCTC-binding factor zinc finger protein (CTCF) binding sites. The genes in this “archipelago” of neighbourhood genes mediate a similar repertoire of functions as FoxO3, including stress resistance, nutrient sensing, cell proliferation, autophagy, apoptosis and stem cell maintenance. The 7.3 Mb gene domain was highly conserved across species, indicating evolutionary importance. We believe that FOXO3 serves as the hub for an “interactome” involved in healthy aging, including cardiovascular disease reduction, in those with favorable FOXO3 genotypes. In support, we found that cellular stress (H 2 O 2 ) could stimulate FOXO3 expression in 20 lymphoblastoid cell lines, being 3-fold stronger for those with a favorable FOXO3 genotype. In FISH experiments, stress-induced activation of FOXO3 caused it to move towards its neighboring genes as suggested by our genomic data. In conclusion, we have shown, for the first time, that FOXO3 is at the central hub of a gene network on chromosome 6 involved in cell protection and healthy aging. The concept of “gene factories” may apply more broadly to genome and genetic mechanisms involved in cardiovascular disease etiology.


2015 ◽  
Vol 112 (47) ◽  
pp. E6456-E6465 ◽  
Author(s):  
Adrian L. Sanborn ◽  
Suhas S. P. Rao ◽  
Su-Chen Huang ◽  
Neva C. Durand ◽  
Miriam H. Huntley ◽  
...  

We recently used in situ Hi-C to create kilobase-resolution 3D maps of mammalian genomes. Here, we combine these maps with new Hi-C, microscopy, and genome-editing experiments to study the physical structure of chromatin fibers, domains, and loops. We find that the observed contact domains are inconsistent with the equilibrium state for an ordinary condensed polymer. Combining Hi-C data and novel mathematical theorems, we show that contact domains are also not consistent with a fractal globule. Instead, we use physical simulations to study two models of genome folding. In one, intermonomer attraction during polymer condensation leads to formation of an anisotropic “tension globule.” In the other, CCCTC-binding factor (CTCF) and cohesin act together to extrude unknotted loops during interphase. Both models are consistent with the observed contact domains and with the observation that contact domains tend to form inside loops. However, the extrusion model explains a far wider array of observations, such as why loops tend not to overlap and why the CTCF-binding motifs at pairs of loop anchors lie in the convergent orientation. Finally, we perform 13 genome-editing experiments examining the effect of altering CTCF-binding sites on chromatin folding. The convergent rule correctly predicts the affected loops in every case. Moreover, the extrusion model accurately predicts in silico the 3D maps resulting from each experiment using only the location of CTCF-binding sites in the WT. Thus, we show that it is possible to disrupt, restore, and move loops and domains using targeted mutations as small as a single base pair.


2019 ◽  
Author(s):  
Nathan D. Kopp ◽  
Kayla R. Nygaard ◽  
Katherine B. McCullough ◽  
Susan E. Maloney ◽  
Harrison W. Gabel ◽  
...  

AbstractGtf2ird1 and Gtf2i may mediate aspects of the cognitive and behavioral phenotypes of Williams Syndrome (WS) – a microdeletion syndrome encompassing these transcription factors (TFs). Knockout mouse models of each TF show behavioral phenotypes. Here we identify their genomic binding sites in the developing brain, and test for additive effects of their mutation on transcription and behavior. Both TFs target constrained chromatin modifier and synaptic protein genes, including a significant number of ASD genes. They bind promoters, strongly overlap CTCF binding and TAD boundaries, and moderately overlap each other, suggesting epistatic effects. We used single and double mutants to test whether mutating both TFs will modify transcriptional and behavioral phenotypes of single Gtf2ird1 mutants. Despite little difference in DNA-binding and transcriptome-wide expression, Gtf2ird1 mutation caused balance, marble burying, and conditioned fear phenotypes. However, mutating Gtf2i in addition to Gtf2ird1 did not further modify transcriptomic or most behavioral phenotypes, suggesting Gtf2ird1 mutation alone is sufficient.


2021 ◽  
Vol 118 (46) ◽  
pp. e2113579118
Author(s):  
Yuko Hasegawa ◽  
Kevin Struhl

Using a tamoxifen-inducible time-course ChIP-sequencing (ChIP-seq) approach, we show that the ubiquitous transcription factor SP1 has different binding dynamics at its target sites in the human genome. SP1 very rapidly reaches maximal binding levels at some sites, but binding kinetics at other sites is biphasic, with rapid half-maximal binding followed by a considerably slower increase to maximal binding. While ∼70% of SP1 binding sites are located at promoter regions, loci with slow SP1 binding kinetics are enriched in enhancer and Polycomb-repressed regions. Unexpectedly, SP1 sites with fast binding kinetics tend to have higher quality and more copies of the SP1 sequence motif. Different cobinding factors associate near SP1 binding sites depending on their binding kinetics and on their location at promoters or enhancers. For example, NFY and FOS are preferentially associated near promoter-bound SP1 sites with fast binding kinetics, whereas DNA motifs of ETS and homeodomain proteins are preferentially observed at sites with slow binding kinetics. At promoters but not enhancers, proteins involved in sumoylation and PML bodies associate more strongly with slow SP1 binding sites than with the fast binding sites. The speed of SP1 binding is not associated with nucleosome occupancy, and it is not necessarily coupled to higher transcriptional activity. These results with SP1 are in contrast to those of human TBP, indicating that there is no common mechanism affecting transcription factor binding kinetics. The biphasic kinetics at some SP1 target sites suggest the existence of distinct chromatin states at these loci in different cells within the overall population.


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