scholarly journals Chromatin accessibility dynamics of myogenesis at single cell resolution

2017 ◽  
Author(s):  
Hannah A. Pliner ◽  
Jonathan Packer ◽  
José L. McFaline-Figueroa ◽  
Darren A. Cusanovich ◽  
Riza Daza ◽  
...  

AbstractOver a million DNA regulatory elements have been cataloged in the human genome, but linking these elements to the genes that they regulate remains challenging. We introduce Cicero, a statistical method that connects regulatory elements to target genes using single cell chromatin accessibility data. We apply Cicero to investigate how thousands of dynamically accessible elements orchestrate gene regulation in differentiating myoblasts. Groups of co-accessible regulatory elements linked by Cicero meet criteria of “chromatin hubs”, in that they are physically proximal, interact with a common set of transcription factors, and undergo coordinated changes in histone marks that are predictive of gene expression. Pseudotemporal analysis revealed a subset of elements bound by MYOD in myoblasts that exhibit early opening, potentially serving as the initial sites of recruitment of chromatin remodeling and histone-modifying enzymes. The methodological framework described here constitutes a powerful new approach for elucidating the architecture, grammar and mechanisms of cis-regulation on a genome-wide basis.

Genes ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 24
Author(s):  
Jianfei Wu ◽  
Fan Gao ◽  
Tongtong Li ◽  
Haixia Guo ◽  
Li Zhang ◽  
...  

Auxin has a profound impact on plant physiology and participates in almost all aspects of plant development processes. Auxin exerts profound pleiotropic effects on plant growth and differentiation by regulating the auxin response genes’ expressions. The classical auxin reaction is usually mediated by auxin response factors (ARFs), which bind to the auxin response element (AuxRE) in the promoter region of the target gene. Experiments have generated only a limited number of plant genes with well-characterized functions. It is still unknown how many genes respond to exogenous auxin treatment. An economical and effective method was proposed for the genome-wide discovery of genes responsive to auxin in a model plant, Arabidopsis thaliana (A. thaliana). Our method relies on cis-regulatory-element-based targeted gene finding across different promoters in a genome. We first exploit and analyze auxin-specific cis-regulatory elements for the transcription of the target genes, and then identify putative auxin responsive genes whose promoters contain the elements in the collection of over 25,800 promoters in the A. thaliana genome. Evaluating our result by comparing with a published database and the literature, we found that this method has an accuracy rate of 65.2% (309/474) for predicting candidate genes responsive to auxin. Chromosome distribution and annotation of the putative auxin-responsive genes predicted here were also mined. The results can markedly decrease the number of identified but merely potential auxin target genes and also provide useful clues for improving the annotation of gene that lack functional information.


2019 ◽  
Author(s):  
Florian Schmidt ◽  
Alexander Marx ◽  
Marie Hebel ◽  
Martin Wegner ◽  
Nina Baumgarten ◽  
...  

AbstractUnderstanding the complexity of transcriptional regulation is a major goal of computational biology. Because experimental linkage of regulatory sites to genes is challenging, computational methods considering epigenomics data have been proposed to create tissue-specific regulatory maps. However, we showed that these approaches are not well suited to account for the variations of the regulatory landscape between cell-types. To overcome these drawbacks, we developed a new method called STITCHIT, that identifies and links putative regulatory sites to genes. Within STITCHIT, we consider the chromatin accessibility signal of all samples jointly to identify regions exhibiting a signal variation related to the expression of a distinct gene. STITCHIToutperforms previous approaches in various validation experiments and was used with a genome-wide CRISPR-Cas9 screen to prioritize novel doxorubicin-resistance genes and their associated non-coding regulatory regions. We believe that our work paves the way for a more refined understanding of transcriptional regulation at the gene-level.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Wanwen Zeng ◽  
Xi Chen ◽  
Zhana Duren ◽  
Yong Wang ◽  
Rui Jiang ◽  
...  

Abstract Characterizing and interpreting heterogeneous mixtures at the cellular level is a critical problem in genomics. Single-cell assays offer an opportunity to resolve cellular level heterogeneity, e.g., scRNA-seq enables single-cell expression profiling, and scATAC-seq identifies active regulatory elements. Furthermore, while scHi-C can measure the chromatin contacts (i.e., loops) between active regulatory elements to target genes in single cells, bulk HiChIP can measure such contacts in a higher resolution. In this work, we introduce DC3 (De-Convolution and Coupled-Clustering) as a method for the joint analysis of various bulk and single-cell data such as HiChIP, RNA-seq and ATAC-seq from the same heterogeneous cell population. DC3 can simultaneously identify distinct subpopulations, assign single cells to the subpopulations (i.e., clustering) and de-convolve the bulk data into subpopulation-specific data. The subpopulation-specific profiles of gene expression, chromatin accessibility and enhancer-promoter contact obtained by DC3 provide a comprehensive characterization of the gene regulatory system in each subpopulation.


2018 ◽  
Author(s):  
Longqi Liu ◽  
Chuanyu Liu ◽  
Andrés Quintero ◽  
Liang Wu ◽  
Yue Yuan ◽  
...  

AbstractIntegrative analysis of multi-omics layers at single cell level is critical for accurate dissection of cell-to-cell variation within certain cell populations. Here we report scCAT-seq, a technique for simultaneously assaying chromatin accessibility and the transcriptome within the same single cell. We show that the combined single cell signatures enable accurate construction of regulatory relationships between cis-regulatory elements and the target genes at single-cell resolution, providing a new dimension of features that helps direct discovery of regulatory patterns specific to distinct cell identities. Moreover, we generated the first single cell integrated maps of chromatin accessibility and transcriptome in human pre-implantation embryos and demonstrated the robustness of scCAT-seq in the precise dissection of master transcription factors in cells of distinct states during embryo development. The ability to obtain these two layers of omics data will help provide more accurate definitions of “single cell state” and enable the deconvolution of regulatory heterogeneity from complex cell populations.


2017 ◽  
Author(s):  
Dinesh Manandhar ◽  
Lingyun Song ◽  
Ami Kabadi ◽  
Jennifer Kwon ◽  
Lee Edsall ◽  
...  

Our current understanding of cellular transdifferentiation systems is limited. It is oftentimes unknown, at a genome-wide scale, how much transdifferentiated cells differ quantitatively from both the starting cells and the target cells. Focusing on transdifferentiation of primary human skin fibroblasts by forced expression of myogenic transcription factor MyoD, we performed quantitative analyses of gene expression and chromatin accessibility profiles of transdifferentiated cells compared to fibroblasts and myoblasts. In this system, we find that while many of the early muscle marker genes are reprogrammed, global gene expression and accessibility changes are still incomplete when compared to myoblasts. In addition, we find evidence of epigenetic memory in the transdifferentiated cells, with reminiscent features of fibroblasts being visible both in chromatin accessibility and gene expression. Quantitative analyses revealed a continuum of changes in chromatin accessibility induced by MyoD, and a strong correlation between chromatin-remodeling deficiencies and incomplete gene expression reprogramming. Classification analyses identified genetic and epigenetic features that distinguish reprogrammed from non-reprogrammed sites, and suggested ways to potentially improve transdifferentiation efficiency. Our approach for combining gene expression, DNA accessibility, and protein-DNA binding data to quantify and characterize the efficiency of cellular transdifferentiation on a genome-wide scale can be applied to any transdifferentiation system.


Science ◽  
2018 ◽  
Vol 362 (6413) ◽  
pp. eaav1898 ◽  
Author(s):  
M. Ryan Corces ◽  
Jeffrey M. Granja ◽  
Shadi Shams ◽  
Bryan H. Louie ◽  
Jose A. Seoane ◽  
...  

We present the genome-wide chromatin accessibility profiles of 410 tumor samples spanning 23 cancer types from The Cancer Genome Atlas (TCGA). We identify 562,709 transposase-accessible DNA elements that substantially extend the compendium of known cis-regulatory elements. Integration of ATAC-seq (the assay for transposase-accessible chromatin using sequencing) with TCGA multi-omic data identifies a large number of putative distal enhancers that distinguish molecular subtypes of cancers, uncovers specific driving transcription factors via protein-DNA footprints, and nominates long-range gene-regulatory interactions in cancer. These data reveal genetic risk loci of cancer predisposition as active DNA regulatory elements in cancer, identify gene-regulatory interactions underlying cancer immune evasion, and pinpoint noncoding mutations that drive enhancer activation and may affect patient survival. These results suggest a systematic approach to understanding the noncoding genome in cancer to advance diagnosis and therapy.


Blood ◽  
2012 ◽  
Vol 119 (16) ◽  
pp. 3724-3733 ◽  
Author(s):  
Louis C. Doré ◽  
Timothy M. Chlon ◽  
Christopher D. Brown ◽  
Kevin P. White ◽  
John D. Crispino

Abstract There are many examples of transcription factor families whose members control gene expression profiles of diverse cell types. However, the mechanism by which closely related factors occupy distinct regulatory elements and impart lineage specificity is largely undefined. Here we demonstrate on a genome wide scale that the hematopoietic GATA factors GATA-1 and GATA-2 bind overlapping sets of genes, often at distinct sites, as a means to differentially regulate target gene expression and to regulate the balance between proliferation and differentiation. We also reveal that the GATA switch, which entails a chromatin occupancy exchange between GATA2 and GATA1 in the course of differentiation, operates on more than one-third of GATA1 bound genes. The switch is equally likely to lead to transcriptional activation or repression; and in general, GATA1 and GATA2 act oppositely on switch target genes. In addition, we show that genomic regions co-occupied by GATA2 and the ETS factor ETS1 are strongly enriched for regions marked by H3K4me3 and occupied by Pol II. Finally, by comparing GATA1 occupancy in erythroid cells and megakaryocytes, we find that the presence of ETS factor motifs is a major discriminator of megakaryocyte versus red cell specification.


2021 ◽  
Author(s):  
Tyler Hansen ◽  
Emily Hodges

Massively parallel reporter assays test the capacity of putative cis-regulatory elements (CREs) to drive transcription on a genome-wide scale. In nearly all cases, chromatin accessibility is necessary to drive activity, so most CREs are inactive due to chromatin context rather than intrinsic DNA sequence properties. Here, we combined assay for transposase-accessible chromatin (ATAC-seq) with self-transcribing active regulatory region sequencing (STARR-seq) to selectively assay the regulatory potential of nucleosome-free DNA genome-wide. Our approach enabled high-resolution testing of ~50 million unique DNA fragments tiling ~101,000 accessible chromatin regions in human lymphoblastoid cells. To illustrate the application of our approach, we show that 30% of all accessible regions contain an activator, a silencer or both. Benchmarking against standard ATAC-seq, our approach faithfully captures chromatin accessibility and transcription factor (TF) footprints with high signal-to-noise. Integrating three layers of genomic information (accessibility, TF occupancy, and activity) provided by ATAC-STARR-seq, we stratified active and silent CREs by the presence of several TF footprints and show that CREs with specific TF combinations are associated with distinct gene regulatory pathways. Altogether, these data highlight the power of ATAC-STARR-seq to comprehensively investigate the regulatory landscape of the human genome from a single DNA source.


2021 ◽  
Author(s):  
Hao Yu ◽  
Na Ai ◽  
Ping Peng ◽  
Yu wen Ke ◽  
Xue peng Chen ◽  
...  

The regulatory programs driving early organogenesis in human is complex and still poorly understood. We performed parallel profiling of gene expression and chromatin accessibility to 28 human fetal tissue samples representing 14 organs in the first trimester. Collectively, we have generated 415,793 single-cell profiles. By integration analysis of transcriptome and chromatin accessibility, we detected 225 distinct cell types and 848,475 candidate accessible cis-regulatory elements (aCREs). By linking regulatory elements to their putative target genes, we identified not only 108,699 enhancers, but also 23,392 silencers elements. We uncovered thousands of genes regulated by both enhancers and silencers in an organ or cell-type-specific manner. Furthermore, our unique approach revealed a substantial proportion of distal DNA elements are transcribed CREs (tCREs), which show both open chromatin signal and transcription initiation activity of non-coding transcript. The landscape of fetal cis-regulatory elements facilitates the interpretation of the genetic variant of complex disease and infer the cell type of origin for cancer. Overall, our data provide a comprehensive map of the fetal cis-regulatory elements at single-cell resolution and a valuable resource for future study of human development and disease.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Timothy Barry ◽  
Xuran Wang ◽  
John A. Morris ◽  
Kathryn Roeder ◽  
Eugene Katsevich

AbstractSingle-cell CRISPR screens are a promising biotechnology for mapping regulatory elements to target genes at genome-wide scale. However, technical factors like sequencing depth impact not only expression measurement but also perturbation detection, creating a confounding effect. We demonstrate on two single-cell CRISPR screens how these challenges cause calibration issues. We propose SCEPTRE: analysis of single-cell perturbation screens via conditional resampling, which infers associations between perturbations and expression by resampling the former according to a working model for perturbation detection probability in each cell. SCEPTRE demonstrates very good calibration and sensitivity on CRISPR screen data, yielding hundreds of new regulatory relationships supported by orthogonal biological evidence.


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