Profiling of chromatin accessibility identifies transcription factor binding sites across the genome of Aspergillus species

Abstract Background The identification of open chromatin regions and transcription factor binding sites (TFBs) is an important step in understanding the regulation of gene expression in diverse species. ATAC-seq is a technique used for such purpose by providing high-resolution measurements of chromatin accessibility revealed through integration of Tn5 transposase. However, the existence of cell walls in filamentous fungi and associated difficulty in purifying nuclei have precluded the routine application of this technique, leading to a lack of experimentally determined and computationally inferred data on the identity of genome-wide cis-regulatory elements (CREs) and TFBs. In this study, we constructed an ATAC-seq platform suitable for filamentous fungi and generated ATAC-seq libraries of Aspergillus niger and Aspergillus oryzae grown under a variety of conditions. Results We applied the ATAC-seq assay for filamentous fungi to delineate the syntenic orthologue and differentially changed chromatin accessibility regions among different Aspergillus species, during different culture conditions, and among specific TF-deleted strains. The syntenic orthologues of accessible regions were responsible for the conservative functions across Aspergillus species, while regions differentially changed between culture conditions and TFs mutants drove differential gene expression programs. Importantly, we suggest criteria to determine TFBs through the analysis of unbalanced cleavage of distinct TF-bound DNA strands by Tn5 transposase. Based on this criterion, we constructed data libraries of the in vivo genomic footprint of A. niger under distinct conditions, and generated a database of novel transcription factor binding motifs through comparison of footprints in TF-deleted strains. Furthermore, we validated the novel TFBs in vivo through an artificial synthetic minimal promoter system. Conclusions We characterized the chromatin accessibility regions of filamentous fungi species, and identified a complete TFBs map by ATAC-seq, which provides valuable data for future analyses of transcriptional regulation in filamentous fungi.

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Profiling of chromatin accessibility across Aspergillus species and identification of transcription factor binding sites in the Aspergillus genome using filamentous fungi ATAC-seq

10.1101/857284 ◽

2019 ◽

Author(s):

Lianggang Huang ◽

Xuejie Li ◽

Liangbo Dong ◽

Bin Wang ◽

Li Pan

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Filamentous Fungi ◽

Binding Sites ◽

Regulatory Elements ◽

Transcription Factor Binding ◽

Chromatin Accessibility ◽

Open Chromatin ◽

Factor Binding ◽

Tn5 Transposase

AbstractTo identify cis-regulatory elements (CREs) and motifs of TF binding is an important step in understanding the regulatory functions of TF binding and gene expression. The lack of experimentally determined and computationally inferred data means that the genome-wide CREs and TF binding sites (TFBs) in filamentous fungi remain unknown. ATAC-seq is a technique that provides a high-resolution measurement of chromatin accessibility to Tn5 transposase integration. In filamentous fungi, the existence of cell walls and the difficulty in purifying nuclei have prevented the routine application of this technique. Herein, we modified the ATAC-seq protocol in filamentous fungi to identify and map open chromatin and TF-binding sites on a genome-scale. We applied the assay for ATAC-seq among different Aspergillus species, during different culture conditions, and among TF-deficient strains to delineate open chromatin regions and TFBs across each genome. The syntenic orthologues regions and differential changes regions of chromatin accessibility were responsible for functional conservative regulatory elements and differential gene expression in the Aspergillus genome respectively. Importantly, 17 and 15 novel transcription factor binding motifs that were enriched in the genomic footprints identified from ATAC-seq data of A. niger, were verified in vivo by our artificial synthetic minimal promoter system, respectively. Furthermore, we first confirmed the strand-specific patterns of Tn5 transposase around the binding sites of known TFs by comparing ATAC-seq data of TF-deficient strains with the data from a wild-type strain.

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Bioinformatics Analysis of SNPs in IL-6 Gene Promoter of Jinghai Yellow Chickens

Genes ◽

10.3390/genes9090446 ◽

2018 ◽

Vol 9 (9) ◽

pp. 446 ◽

Cited By ~ 3

Author(s):

Shijie Xin ◽

Xiaohui Wang ◽

Guojun Dai ◽

Jingjing Zhang ◽

Tingting An ◽

...

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Binding Sites ◽

Promoter Region ◽

Bioinformatics Analysis ◽

Cpg Islands ◽

Regulatory Region ◽

Transcription Factor Binding Sites ◽

Transcription Factor Binding ◽

Factor Binding

The proinflammatory cytokine, interleukin-6 (IL-6), plays a critical role in many chronic inflammatory diseases, particularly inflammatory bowel disease. To investigate the regulation of IL-6 gene expression at the molecular level, genomic DNA sequencing of Jinghai yellow chickens (Gallus gallus) was performed to detect single-nucleotide polymorphisms (SNPs) in the region −2200 base pairs (bp) upstream to 500 bp downstream of IL-6. Transcription factor binding sites and CpG islands in the IL-6 promoter region were predicted using bioinformatics software. Twenty-eight SNP sites were identified in IL-6. Four of these 28 SNPs, three [−357 (G > A), −447 (C > G), and −663 (A > G)] in the 5′ regulatory region and one in the 3′ non-coding region [3177 (C > T)] are not labelled in GenBank. Bioinformatics analysis revealed 11 SNPs within the promoter region that altered putative transcription factor binding sites. Furthermore, the C-939G mutation in the promoter region may change the number of CpG islands, and SNPs in the 5′ regulatory region may influence IL-6 gene expression by altering transcription factor binding or CpG methylation status. Genetic diversity analysis revealed that the newly discovered A-663G site significantly deviated from Hardy-Weinberg equilibrium. These results provide a basis for further exploration of the promoter function of the IL-6 gene and the relationships of these SNPs to intestinal inflammation resistance in chickens.

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Genomic Promoter Analysis Predicts Functional Transcription Factor Binding

Advances in Bioinformatics ◽

10.1155/2008/369830 ◽

2008 ◽

Vol 2008 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

J. Sunil Rao ◽

Suresh Karanam ◽

Colleen D. McCabe ◽

Carlos S. Moreno

Keyword(s):

Transcription Factor ◽

Binding Sites ◽

Transcription Factor Binding Sites ◽

Transcription Factor Binding ◽

Proximal Promoter ◽

Marginal Effect ◽

Promoter Sequences ◽

Factor Binding ◽

Functional Transcription Factor

Background. The computational identification of functional transcription factor binding sites (TFBSs) remains a major challenge of computational biology. Results. We have analyzed the conserved promoter sequences for the complete set of human RefSeq genes using our conserved transcription factor binding site (CONFAC) software. CONFAC identified 16296 human-mouse ortholog gene pairs, and of those pairs, 9107 genes contained conserved TFBS in the 3 kb proximal promoter and first intron. To attempt to predict in vivo occupancy of transcription factor binding sites, we developed a novel marginal effect isolator algorithm that builds upon Bayesian methods for multigroup TFBS filtering and predicted the in vivo occupancy of two transcription factors with an overall accuracy of 84%. Conclusion. Our analyses show that integration of chromatin immunoprecipitation data with conserved TFBS analysis can be used to generate accurate predictions of functional TFBS. They also show that TFBS cooccurrence can be used to predict transcription factor binding to promoters in vivo.

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Assessing the model transferability for prediction of transcription factor binding sites based on chromatin accessibility

BMC Bioinformatics ◽

10.1186/s12859-017-1769-7 ◽

2017 ◽

Vol 18 (1) ◽

Cited By ~ 12

Author(s):

Sheng Liu ◽

Cristina Zibetti ◽

Jun Wan ◽

Guohua Wang ◽

Seth Blackshaw ◽

...

Keyword(s):

Transcription Factor ◽

Binding Sites ◽

Transcription Factor Binding Sites ◽

Transcription Factor Binding ◽

Chromatin Accessibility ◽

Factor Binding ◽

Model Transferability

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WAPL maintains dynamic cohesin to preserve lineage specific distal gene regulation

10.1101/731141 ◽

2019 ◽

Cited By ~ 2

Author(s):

Ning Qing Liu ◽

Michela Maresca ◽

Teun van den Brand ◽

Luca Braccioli ◽

Marijne M.G.A. Schijns ◽

...

Keyword(s):

Gene Expression ◽

Gene Regulation ◽

Transcription Factor ◽

Binding Sites ◽

Transcription Factor Binding ◽

Ctcf Binding ◽

Release Factor ◽

Factor Binding ◽

Active Enhancer ◽

Lineage Specific Genes

SUMMARYThe cohesin complex plays essential roles in sister chromatin cohesin, chromosome organization and gene expression. The role of cohesin in gene regulation is incompletely understood. Here, we report that the cohesin release factor WAPL is crucial for maintaining a pool of dynamic cohesin bound to regions that are associated with lineage specific genes in mouse embryonic stem cells. These regulatory regions are enriched for active enhancer marks and transcription factor binding sites, but largely devoid of CTCF binding sites. Stabilization of cohesin, which leads to a loss of dynamic cohesin from these regions, does not affect transcription factor binding or active enhancer marks, but does result in changes in promoter-enhancer interactions and downregulation of genes. Acute cohesin depletion can phenocopy the effect of WAPL depletion, showing that cohesin plays a crucial role in maintaining expression of lineage specific genes. The binding of dynamic cohesin to chromatin is dependent on the pluripotency transcription factor OCT4, but not NANOG. Finally, dynamic cohesin binding sites are also found in differentiated cells, suggesting that they represent a general regulatory principle. We propose that cohesin dynamically binding to regulatory sites creates a favorable spatial environment in which promoters and enhancers can communicate to ensure proper gene expression.HIGHLIGHTSThe cohesin release factor WAPL is crucial for maintaining a pluripotency-specific phenotype.Dynamic cohesin is enriched at lineage specific loci and overlaps with binding sites of pluripotency transcription factors.Expression of lineage specific genes is maintained by dynamic cohesin binding through the formation of promoter-enhancer associated self-interaction domains.CTCF-independent cohesin binding to chromatin is controlled by the pioneer factor OCT4.

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Regulatory plasticity within a complex cytokine-sensing mammary enhancer during lactation

10.1101/2020.06.04.134429 ◽

2020 ◽

Author(s):

Hye Kyung Lee ◽

Chengyu Liu ◽

Lothar Hennighausen

Keyword(s):

Gene Expression ◽

Transcription Factor ◽

Transcription Factors ◽

Transcription Factor Binding ◽

Mouse Genetics ◽

Biological Information ◽

Mammary Tissue ◽

Factor Binding ◽

Biological Importance

AbstractEnhancers are transcription factor platforms that synergize with promoters to activate gene expression up to several-thousand-fold. While genome-wide structural studies are used to predict enhancers, the in vivo significance is less clear. Specifically, the biological importance of individual transcription factors within enhancer complexes remains to be understood. Here we investigate the structural and biological importance of individual transcription factor binding sites and redundancy among transcription components within a complex enhancer in vivo. The Csn1s2b gene is expressed exclusively in mammary tissue and activated several thousand-fold during pregnancy and lactation. Using ChIP-seq we identified a complex lactation-specific candidate enhancer that binds multiple transcription factors and coincides with activating histone marks. Using experimental mouse genetics, we determined that deletion of canonical binding motifs for the transcription factors NFIB and STAT5, individually and combined, had a limited biological impact. Loss of these sites led to a shift of transcription factor binding to juxtaposed sites, suggesting exceptional plasticity that does not require direct protein-DNA interactions. Additional deletions revealed the critical importance of a non-canonical STAT5 binding site for enhancer activity. Our data also suggest that enhancer RNAs are not required for the activity of this specific enhancer. While ChIP-seq experiments predicted an additional candidate intronic enhancer, its deletion did not adversely affect gene expression, emphasizing the limited biological information provided by structural data. Our study provides comprehensive insight into the anatomy and biology of a composite mammary enhancer that activates its target gene several hundred-fold during lactation.

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