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McCann AA, Baniulyte G, Woodstock DL, Sammons MA. Context dependent activity of p63-bound gene regulatory elements. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.09.593326. [PMID: 38766006 PMCID: PMC11100809 DOI: 10.1101/2024.05.09.593326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
The p53 family of transcription factors regulate numerous organismal processes including the development of skin and limbs, ciliogenesis, and preservation of genetic integrity and tumor suppression. p53 family members control these processes and gene expression networks through engagement with DNA sequences within gene regulatory elements. Whereas p53 binding to its cognate recognition sequence is strongly associated with transcriptional activation, p63 can mediate both activation and repression. How the DNA sequence of p63-bound gene regulatory elements is linked to these varied activities is not yet understood. Here, we use massively parallel reporter assays (MPRA) in a range of cellular and genetic contexts to investigate the influence of DNA sequence on p63-mediated transcription. Most regulatory elements with a p63 response element motif (p63RE) activate transcription, with those sites bound by p63 more frequently or adhering closer to canonical p53 family response element sequences driving higher transcriptional output. The most active regulatory elements are those also capable of binding p53. Elements uniquely bound by p63 have varied activity, with p63RE-mediated repression associated with lower overall GC content in flanking sequences. Comparison of activity across cell lines suggests differential activity of elements may be regulated by a combination of p63 abundance or context-specific cofactors. Finally, changes in p63 isoform expression dramatically alters regulatory element activity, primarily shifting inactive elements towards a strong p63-dependent activity. Our analysis of p63-bound gene regulatory elements provides new insight into how sequence, cellular context, and other transcription factors influence p63-dependent transcription. These studies provide a framework for understanding how p63 genomic binding locally regulates transcription. Additionally, these results can be extended to investigate the influence of sequence content, genomic context, chromatin structure on the interplay between p63 isoforms and p53 family paralogs.
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Affiliation(s)
- Abby A. McCann
- Department of Biological Sciences and The RNA Institute, University at Albany, State University of New York. 1400 washington Ave, Albany, NY 12222
| | - Gabriele Baniulyte
- Department of Biological Sciences and The RNA Institute, University at Albany, State University of New York. 1400 washington Ave, Albany, NY 12222
| | - Dana L. Woodstock
- Department of Biological Sciences and The RNA Institute, University at Albany, State University of New York. 1400 washington Ave, Albany, NY 12222
| | - Morgan A. Sammons
- Department of Biological Sciences and The RNA Institute, University at Albany, State University of New York. 1400 washington Ave, Albany, NY 12222
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2
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Wallis M, Xu Q, Krawczyk M, Skowronska-Krawczyk D. Evolution of the enhancer-rich regulatory region of the gene for the cell-type specific transcription factor POU1F1. Heliyon 2024; 10:e28640. [PMID: 38590853 PMCID: PMC10999999 DOI: 10.1016/j.heliyon.2024.e28640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 03/14/2024] [Accepted: 03/21/2024] [Indexed: 04/10/2024] Open
Abstract
Precise spatio-temporal expression of genes in organogenesis is regulated by the coordinated interplay of DNA elements such as promoter and enhancers present in the regulatory region of a given locus. POU1F1 transcription factor plays a crucial role in the development of somatotrophs, lactotrophs and thyrotrophs in the anterior pituitary gland, and in maintaining high expression of growth hormone, prolactin and TSH. In mouse, expression of POU1F1 is controlled by a region fenced by two CTCF sites, containing 5 upstream enhancer elements, designated E-A (5' to 3'). Elements C, B and A correspond to elements shown previously to play a role in pituitary development and hormonal expression; functional roles for elements E and D have not been reported. We performed comparative sequence analysis of this regulatory region and discovered that three elements, B, C and E, are present in all vertebrate groups except Agnatha. One very long (>2 kb) element (A) is unique to mammals suggesting a specific change in regulation of the gene in this group. Using DNA accessibility assay (ATAC-seq) we showed that conserved elements in anterior pituitary of four non-mammals are open, suggesting functionality as regulatory elements. We showed that, in many non-mammalian vertebrates, an additional upstream exon closely follows element E, leading to alternatively spliced transcripts. Here, element E functions as an alternative promoter, but in mammals this feature is lost, suggesting conversion of alternative promoter to enhancer. Our work shows that regulation of POU1F1 changed markedly during the course of vertebrate evolution, use of a low number of enhancer elements combined with alternative promoters in non-mammalian vertebrates being replaced by use of a unique combination of regulatory units in mammals. Most importantly, our work suggests that evolutionary conversion of alternate promoter to enhancer could be one of the evolutionary mechanisms of enhancer birth.
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Affiliation(s)
- Michael Wallis
- Department of Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - Qianlan Xu
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California, Irvine, CA, USA
| | - Michal Krawczyk
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, University of California, Irvine, CA, USA
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3
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He AY, Danko CG. Dissection of core promoter syntax through single nucleotide resolution modeling of transcription initiation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.13.583868. [PMID: 38559255 PMCID: PMC10979970 DOI: 10.1101/2024.03.13.583868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Our understanding of how the DNA sequences of cis-regulatory elements encode transcription initiation patterns remains limited. Here we introduce CLIPNET, a deep learning model trained on population-scale PRO-cap data that accurately predicts the position and quantity of transcription initiation with single nucleotide resolution from DNA sequence. Interpretation of CLIPNET revealed a complex regulatory syntax consisting of DNA-protein interactions in five major positions between -200 and +50 bp relative to the transcription start site, as well as more subtle positional preferences among different transcriptional activators. Transcriptional activator and core promoter motifs occupy different positions and play distinct roles in regulating initiation, with the former driving initiation quantity and the latter initiation position. We identified core promoter motifs that explain initiation patterns in the majority of promoters and enhancers, including DPR motifs and AT-rich TBP binding sequences in TATA-less promoters. Our results provide insights into the sequence architecture governing transcription initiation.
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Affiliation(s)
- Adam Y. He
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University
- Graduate Field of Computational Biology, Cornell University
| | - Charles G. Danko
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University
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4
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Schember I, Reid W, Sterling-Lentsch G, Halfon MS. Conserved and novel enhancers in the Aedes aegypti single-minded locus recapitulate embryonic ventral midline gene expression. PLoS Genet 2024; 20:e1010891. [PMID: 38683842 PMCID: PMC11081499 DOI: 10.1371/journal.pgen.1010891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 05/09/2024] [Accepted: 04/16/2024] [Indexed: 05/02/2024] Open
Abstract
Transcriptional cis-regulatory modules, e.g., enhancers, control the time and location of metazoan gene expression. While changes in enhancers can provide a powerful force for evolution, there is also significant deep conservation of enhancers for developmentally important genes, with function and sequence characteristics maintained over hundreds of millions of years of divergence. Not well understood, however, is how the overall regulatory composition of a locus evolves, with important outstanding questions such as how many enhancers are conserved vs. novel, and to what extent are the locations of conserved enhancers within a locus maintained? We begin here to address these questions with a comparison of the respective single-minded (sim) loci in the two dipteran species Drosophila melanogaster (fruit fly) and Aedes aegypti (mosquito). sim encodes a highly conserved transcription factor that mediates development of the arthropod embryonic ventral midline. We identify two enhancers in the A. aegypti sim locus and demonstrate that they function equivalently in both transgenic flies and transgenic mosquitoes. One A. aegypti enhancer is highly similar to known Drosophila counterparts in its activity, location, and autoregulatory capability. The other differs from any known Drosophila sim enhancers with a novel location, failure to autoregulate, and regulation of expression in a unique subset of midline cells. Our results suggest that the conserved pattern of sim expression in the two species is the result of both conserved and novel regulatory sequences. Further examination of this locus will help to illuminate how the overall regulatory landscape of a conserved developmental gene evolves.
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Affiliation(s)
- Isabella Schember
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, New York, United States of America
| | - William Reid
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, New York, United States of America
| | - Geyenna Sterling-Lentsch
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, New York, United States of America
| | - Marc S. Halfon
- Department of Biochemistry, University at Buffalo-State University of New York, Buffalo, New York, United States of America
- Department of Biomedical Informatics, University at Buffalo-State University of New York, Buffalo, New York, United States of America
- Department of Biological Sciences, University at Buffalo-State University of New York, Buffalo, New York, United States of America
- New York State Center of Excellence in Bioinformatics & Life Sciences, Buffalo, New York, United States of America
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5
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Chen Z, Cortes L, Gallavotti A. Genetic dissection of cis-regulatory control of ZmWUSCHEL1 expression by type B RESPONSE REGULATORS. PLANT PHYSIOLOGY 2024; 194:2240-2248. [PMID: 38060616 PMCID: PMC10980522 DOI: 10.1093/plphys/kiad652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 11/06/2023] [Indexed: 04/01/2024]
Abstract
Mutations in cis-regulatory regions play an important role in the domestication and improvement of crops by altering gene expression. However, assessing the in vivo impact of cis-regulatory elements (CREs) on transcriptional regulation and phenotypic outcomes remains challenging. Previously, we showed that the dominant Barren inflorescence3 (Bif3) mutant of maize (Zea mays) contains a duplicated copy of the homeobox transcription factor gene ZmWUSCHEL1 (ZmWUS1), named ZmWUS1-B. ZmWUS1-B is controlled by a spontaneously generated novel promoter region that dramatically increases its expression and alters patterning and development of young ears. Overexpression of ZmWUS1-B is caused by a unique enhancer region containing multimerized binding sites for type B RESPONSE REGULATORs (RRs), key transcription factors in cytokinin signaling. To better understand how the enhancer increases the expression of ZmWUS1 in vivo, we specifically targeted the ZmWUS1-B enhancer region by CRISPR-Cas9-mediated editing. A series of deletion events with different numbers of type B RR DNA binding motifs (AGATAT) enabled us to determine how the number of AGATAT motifs impacts in vivo expression of ZmWUS1-B and consequently ear development. In combination with dual-luciferase assays in maize protoplasts, our analysis reveals that AGATAT motifs have an additive effect on ZmWUS1-B expression, while the distance separating AGATAT motifs does not appear to have a meaningful impact, indicating that the enhancer activity derives from the sum of individual CREs. These results also suggest that in maize inflorescence development, there is a threshold of buffering capacity for ZmWUS1 overexpression.
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Affiliation(s)
- Zongliang Chen
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Liz Cortes
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
| | - Andrea Gallavotti
- Waksman Institute of Microbiology, Rutgers University, Piscataway, NJ 08854-8020, USA
- Department of Plant Biology, Rutgers University, New Brunswick, NJ 08901, USA
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6
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Lim F, Solvason JJ, Ryan GE, Le SH, Jindal GA, Steffen P, Jandu SK, Farley EK. Affinity-optimizing enhancer variants disrupt development. Nature 2024; 626:151-159. [PMID: 38233525 PMCID: PMC10830414 DOI: 10.1038/s41586-023-06922-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 11/30/2023] [Indexed: 01/19/2024]
Abstract
Enhancers control the location and timing of gene expression and contain the majority of variants associated with disease1-3. The ZRS is arguably the most well-studied vertebrate enhancer and mediates the expression of Shh in the developing limb4. Thirty-one human single-nucleotide variants (SNVs) within the ZRS are associated with polydactyly4-6. However, how this enhancer encodes tissue-specific activity, and the mechanisms by which SNVs alter the number of digits, are poorly understood. Here we show that the ETS sites within the ZRS are low affinity, and identify a functional ETS site, ETS-A, with extremely low affinity. Two human SNVs and a synthetic variant optimize the binding affinity of ETS-A subtly from 15% to around 25% relative to the strongest ETS binding sequence, and cause polydactyly with the same penetrance and severity. A greater increase in affinity results in phenotypes that are more penetrant and more severe. Affinity-optimizing SNVs in other ETS sites in the ZRS, as well as in ETS, interferon regulatory factor (IRF), HOX and activator protein 1 (AP-1) sites within a wide variety of enhancers, cause gain-of-function gene expression. The prevalence of binding sites with suboptimal affinity in enhancers creates a vulnerability in genomes whereby SNVs that optimize affinity, even slightly, can be pathogenic. Searching for affinity-optimizing SNVs in genomes could provide a mechanistic approach to identify causal variants that underlie enhanceropathies.
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Affiliation(s)
- Fabian Lim
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Biological Sciences Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Joe J Solvason
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
- Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA, USA
| | - Genevieve E Ryan
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Sophia H Le
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Granton A Jindal
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Paige Steffen
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Simran K Jandu
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA
| | - Emma K Farley
- Department of Medicine, University of California San Diego, La Jolla, CA, USA.
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA, USA.
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7
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de Boer CG, Taipale J. Hold out the genome: a roadmap to solving the cis-regulatory code. Nature 2024; 625:41-50. [PMID: 38093018 DOI: 10.1038/s41586-023-06661-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 09/20/2023] [Indexed: 01/05/2024]
Abstract
Gene expression is regulated by transcription factors that work together to read cis-regulatory DNA sequences. The 'cis-regulatory code' - how cells interpret DNA sequences to determine when, where and how much genes should be expressed - has proven to be exceedingly complex. Recently, advances in the scale and resolution of functional genomics assays and machine learning have enabled substantial progress towards deciphering this code. However, the cis-regulatory code will probably never be solved if models are trained only on genomic sequences; regions of homology can easily lead to overestimation of predictive performance, and our genome is too short and has insufficient sequence diversity to learn all relevant parameters. Fortunately, randomly synthesized DNA sequences enable testing a far larger sequence space than exists in our genomes, and designed DNA sequences enable targeted queries to maximally improve the models. As the same biochemical principles are used to interpret DNA regardless of its source, models trained on these synthetic data can predict genomic activity, often better than genome-trained models. Here we provide an outlook on the field, and propose a roadmap towards solving the cis-regulatory code by a combination of machine learning and massively parallel assays using synthetic DNA.
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Affiliation(s)
- Carl G de Boer
- School of Biomedical Engineering, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Jussi Taipale
- Applied Tumor Genomics Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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8
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Loell KJ, Friedman RZ, Myers CA, Corbo JC, Cohen BA, White MA. Transcription factor interactions explain the context-dependent activity of CRX binding sites. PLoS Comput Biol 2024; 20:e1011802. [PMID: 38227575 PMCID: PMC10817189 DOI: 10.1371/journal.pcbi.1011802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 01/26/2024] [Accepted: 01/06/2024] [Indexed: 01/18/2024] Open
Abstract
The effects of transcription factor binding sites (TFBSs) on the activity of a cis-regulatory element (CRE) depend on the local sequence context. In rod photoreceptors, binding sites for the transcription factor (TF) Cone-rod homeobox (CRX) occur in both enhancers and silencers, but the sequence context that determines whether CRX binding sites contribute to activation or repression of transcription is not understood. To investigate the context-dependent activity of CRX sites, we fit neural network-based models to the activities of synthetic CREs composed of photoreceptor TFBSs. The models revealed that CRX binding sites consistently make positive, independent contributions to CRE activity, while negative homotypic interactions between sites cause CREs composed of multiple CRX sites to function as silencers. The effects of negative homotypic interactions can be overcome by the presence of other TFBSs that either interact cooperatively with CRX sites or make independent positive contributions to activity. The context-dependent activity of CRX sites is thus determined by the balance between positive heterotypic interactions, independent contributions of TFBSs, and negative homotypic interactions. Our findings explain observed patterns of activity among genomic CRX-bound enhancers and silencers, and suggest that enhancers may require diverse TFBSs to overcome negative homotypic interactions between TFBSs.
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Affiliation(s)
- Kaiser J. Loell
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
| | - Ryan Z. Friedman
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
| | - Connie A. Myers
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
| | - Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
| | - Barak A. Cohen
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
| | - Michael A. White
- Department of Genetics, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America
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9
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Jindal GA, Bantle AT, Solvason JJ, Grudzien JL, D'Antonio-Chronowska A, Lim F, Le SH, Song BP, Ragsac MF, Klie A, Larsen RO, Frazer KA, Farley EK. Single-nucleotide variants within heart enhancers increase binding affinity and disrupt heart development. Dev Cell 2023; 58:2206-2216.e5. [PMID: 37848026 PMCID: PMC10720985 DOI: 10.1016/j.devcel.2023.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 06/07/2023] [Accepted: 09/20/2023] [Indexed: 10/19/2023]
Abstract
Transcriptional enhancers direct precise gene expression patterns during development and harbor the majority of variants associated with phenotypic diversity, evolutionary adaptations, and disease. Pinpointing which enhancer variants contribute to changes in gene expression and phenotypes is a major challenge. Here, we find that suboptimal or low-affinity binding sites are necessary for precise gene expression during heart development. Single-nucleotide variants (SNVs) can optimize the affinity of ETS binding sites, causing gain-of-function (GOF) gene expression, cell migration defects, and phenotypes as severe as extra beating hearts in the marine chordate Ciona robusta. In human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a SNV within a human GATA4 enhancer increases ETS binding affinity and causes GOF enhancer activity. The prevalence of suboptimal-affinity sites within enhancers creates a vulnerability whereby affinity-optimizing SNVs can lead to GOF gene expression, changes in cellular identity, and organismal-level phenotypes that could contribute to the evolution of novel traits or diseases.
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Affiliation(s)
- Granton A Jindal
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Alexis T Bantle
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joe J Solvason
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jessica L Grudzien
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | | | - Fabian Lim
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sophia H Le
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Benjamin P Song
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michelle F Ragsac
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Adam Klie
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Reid O Larsen
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kelly A Frazer
- Department of Pediatrics, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Department of Medicine, Health Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, School of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
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10
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Uttley K, Papanastasiou AS, Lahne M, Brisbane JM, MacDonald RB, Bickmore WA, Bhatia S. Unique activities of two overlapping PAX6 retinal enhancers. Life Sci Alliance 2023; 6:e202302126. [PMID: 37643867 PMCID: PMC10465922 DOI: 10.26508/lsa.202302126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/31/2023] Open
Abstract
Enhancers play a critical role in development by precisely modulating spatial, temporal, and cell type-specific gene expression. Sequence variants in enhancers have been implicated in diseases; however, establishing the functional consequences of these variants is challenging because of a lack of understanding of precise cell types and developmental stages where the enhancers are normally active. PAX6 is the master regulator of eye development, with a regulatory landscape containing multiple enhancers driving the expression in the eye. Whether these enhancers perform additive, redundant or distinct functions is unknown. Here, we describe the precise cell types and regulatory activity of two PAX6 retinal enhancers, HS5 and NRE. Using a unique combination of live imaging and single-cell RNA sequencing in dual enhancer-reporter zebrafish embryos, we uncover differences in the spatiotemporal activity of these enhancers. Our results show that although overlapping, these enhancers have distinct activities in different cell types and therefore likely nonredundant functions. This work demonstrates that unique cell type-specific activities can be uncovered for apparently similar enhancers when investigated at high resolution in vivo.
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Affiliation(s)
- Kirsty Uttley
- https://ror.org/011jsc803 MRC Human Genetics Unithttps://ror.org/01nrxwf90 , Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Andrew S Papanastasiou
- https://ror.org/011jsc803 MRC Human Genetics Unithttps://ror.org/01nrxwf90 , Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Manuela Lahne
- https://ror.org/02jx3x895 UCL Institute of Ophthalmology, University College London, Greater London, UK
| | - Jennifer M Brisbane
- https://ror.org/011jsc803 MRC Human Genetics Unithttps://ror.org/01nrxwf90 , Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Ryan B MacDonald
- https://ror.org/02jx3x895 UCL Institute of Ophthalmology, University College London, Greater London, UK
| | - Wendy A Bickmore
- https://ror.org/011jsc803 MRC Human Genetics Unithttps://ror.org/01nrxwf90 , Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
| | - Shipra Bhatia
- https://ror.org/011jsc803 MRC Human Genetics Unithttps://ror.org/01nrxwf90 , Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK
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11
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Farley EK. Ciona, an ideal research organism to study the role of enhancers. Genesis 2023; 61:e23577. [PMID: 38009359 DOI: 10.1002/dvg.23577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/28/2023]
Affiliation(s)
- Emma Kirsten Farley
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, California, USA
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12
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Arnold M, Stengel KR. Emerging insights into enhancer biology and function. Transcription 2023; 14:68-87. [PMID: 37312570 PMCID: PMC10353330 DOI: 10.1080/21541264.2023.2222032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 06/15/2023] Open
Abstract
Cell type-specific gene expression is coordinated by DNA-encoded enhancers and the transcription factors (TFs) that bind to them in a sequence-specific manner. As such, these enhancers and TFs are critical mediators of normal development and altered enhancer or TF function is associated with the development of diseases such as cancer. While initially defined by their ability to activate gene transcription in reporter assays, putative enhancer elements are now frequently defined by their unique chromatin features including DNase hypersensitivity and transposase accessibility, bidirectional enhancer RNA (eRNA) transcription, CpG hypomethylation, high H3K27ac and H3K4me1, sequence-specific transcription factor binding, and co-factor recruitment. Identification of these chromatin features through sequencing-based assays has revolutionized our ability to identify enhancer elements on a genome-wide scale, and genome-wide functional assays are now capitalizing on this information to greatly expand our understanding of how enhancers function to provide spatiotemporal coordination of gene expression programs. Here, we highlight recent technological advances that are providing new insights into the molecular mechanisms by which these critical cis-regulatory elements function in gene control. We pay particular attention to advances in our understanding of enhancer transcription, enhancer-promoter syntax, 3D organization and biomolecular condensates, transcription factor and co-factor dependencies, and the development of genome-wide functional enhancer screens.
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Affiliation(s)
- Mirjam Arnold
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Kristy R. Stengel
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Montefiore Einstein Cancer Center, Albert Einstein College of Medicine-Montefiore Health System, Bronx, NY, USA
- Ruth L. and David S. Gottesman Institute for Stem Cell and Regenerative Medicine Research, Albert Einstein College of Medicine, Bronx, NY, USA
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13
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Pham PD, Lu H, Han H, Zhou JJ, Madan A, Wang W, Murre C, Cho KWY. Transcriptional network governing extraembryonic endoderm cell fate choice. Dev Biol 2023; 502:20-37. [PMID: 37423592 PMCID: PMC10550205 DOI: 10.1016/j.ydbio.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Accepted: 07/05/2023] [Indexed: 07/11/2023]
Abstract
The mechanism by which transcription factor (TF) network instructs cell-type-specific transcriptional programs to drive primitive endoderm (PrE) progenitors to commit to parietal endoderm (PE) versus visceral endoderm (VE) cell fates remains poorly understood. To address the question, we analyzed the single-cell transcriptional signatures defining PrE, PE, and VE cell states during the onset of the PE-VE lineage bifurcation. By coupling with the epigenomic comparison of active enhancers unique to PE and VE cells, we identified GATA6, SOX17, and FOXA2 as central regulators for the lineage divergence. Transcriptomic analysis of cXEN cells, an in vitro model for PE cells, after the acute depletion of GATA6 or SOX17 demonstrated that these factors induce Mycn, imparting the self-renewal properties of PE cells. Concurrently, they suppress the VE gene program, including key genes like Hnf4a and Ttr, among others. We proceeded with RNA-seq analysis on cXEN cells with FOXA2 knockout, in conjunction with GATA6 or SOX17 depletion. We found FOXA2 acts as a potent suppressor of Mycn while simultaneously activating the VE gene program. The antagonistic gene regulatory activities of GATA6/SOX17 and FOXA2 in promoting alternative cell fates, and their physical co-bindings at the enhancers provide molecular insights to the plasticity of the PrE lineage. Finally, we show that the external cue, BMP signaling, promotes the VE cell fate by activation of VE TFs and repression of PE TFs including GATA6 and SOX17. These data reveal a putative core gene regulatory module that underpins PE and VE cell fate choice.
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Affiliation(s)
- Paula Duyen Pham
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Hanbin Lu
- School of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, 92039, USA
| | - Han Han
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Jeff Jiajing Zhou
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Aarushi Madan
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Wenqi Wang
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Cornelis Murre
- School of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, 92039, USA
| | - Ken W Y Cho
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
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14
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Jores T, Hamm M, Cuperus JT, Queitsch C. Frontiers and techniques in plant gene regulation. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102403. [PMID: 37331209 DOI: 10.1016/j.pbi.2023.102403] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/12/2023] [Accepted: 05/19/2023] [Indexed: 06/20/2023]
Abstract
Understanding plant gene regulation has been a priority for generations of plant scientists. However, due to its complex nature, the regulatory code governing plant gene expression has yet to be deciphered comprehensively. Recently developed methods-often relying on next-generation sequencing technology and state-of-the-art computational approaches-have started to further our understanding of the gene regulatory logic used by plants. In this review, we discuss these methods and the insights into the regulatory code of plants that they can yield.
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Affiliation(s)
- Tobias Jores
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| | - Morgan Hamm
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Josh T Cuperus
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
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15
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Zhu I, Landsman D. Clustered and diverse transcription factor binding underlies cell type specificity of enhancers for housekeeping genes. Genome Res 2023; 33:1662-1672. [PMID: 37884340 PMCID: PMC10691539 DOI: 10.1101/gr.278130.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023]
Abstract
Housekeeping genes are considered to be regulated by common enhancers across different tissues. Here we report that most of the commonly expressed mouse or human genes across different cell types, including more than half of the previously identified housekeeping genes, are associated with cell type-specific enhancers. Furthermore, the binding of most transcription factors (TFs) is cell type-specific. We reason that these cell type specificities are causally related to the collective TF recruitment at regulatory sites, as TFs tend to bind to regions associated with many other TFs and each cell type has a unique repertoire of expressed TFs. Based on binding profiles of hundreds of TFs from HepG2, K562, and GM12878 cells, we show that 80% of all TF peaks overlapping H3K27ac signals are in the top 20,000-23,000 most TF-enriched H3K27ac peak regions, and approximately 12,000-15,000 of these peaks are enhancers (nonpromoters). Those enhancers are mainly cell type-specific and include those linked to the majority of commonly expressed genes. Moreover, we show that the top 15,000 most TF-enriched regulatory sites in HepG2 cells, associated with about 200 TFs, can be predicted largely from the binding profile of as few as 30 TFs. Through motif analysis, we show that major enhancers harbor diverse and clustered motifs from a combination of available TFs uniquely present in each cell type. We propose a mechanism that explains how the highly focused TF binding at regulatory sites results in cell type specificity of enhancers for housekeeping and commonly expressed genes.
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Affiliation(s)
- Iris Zhu
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
| | - David Landsman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland 20894, USA
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16
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Liu Y, Wang Z, Yuan H, Zhu G, Zhang Y. HEAP: a task adaptive-based explainable deep learning framework for enhancer activity prediction. Brief Bioinform 2023; 24:bbad286. [PMID: 37539835 DOI: 10.1093/bib/bbad286] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/05/2023] [Accepted: 07/21/2023] [Indexed: 08/05/2023] Open
Abstract
Enhancers are crucial cis-regulatory elements that control gene expression in a cell-type-specific manner. Despite extensive genetic and computational studies, accurately predicting enhancer activity in different cell types remains a challenge, and the grammar of enhancers is still poorly understood. Here, we present HEAP (high-resolution enhancer activity prediction), an explainable deep learning framework for predicting enhancers and exploring enhancer grammar. The framework includes three modules that use grammar-based reasoning for enhancer prediction. The algorithm can incorporate DNA sequences and epigenetic modifications to obtain better accuracy. We use a novel two-step multi-task learning method, task adaptive parameter sharing (TAPS), to efficiently predict enhancers in different cell types. We first train a shared model with all cell-type datasets. Then we adapt to specific tasks by adding several task-specific subset layers. Experiments demonstrate that HEAP outperforms published methods and showcases the effectiveness of the TAPS, especially for those with limited training samples. Notably, the explainable framework HEAP utilizes post-hoc interpretation to provide insights into the prediction mechanisms from three perspectives: data, model architecture and algorithm, leading to a better understanding of model decisions and enhancer grammar. To the best of our knowledge, HEAP will be a valuable tool for insight into the complex mechanisms of enhancer activity.
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Affiliation(s)
- Yuhang Liu
- School of Computer Science, Chengdu University of Information Technology, 610225, Chengdu, China
| | - Zixuan Wang
- College of Electronics and Information Engieering, Sichuan University, 610065, Chengdu, China
| | - Hao Yuan
- School of Computer Science, Chengdu University of Information Technology, 610225, Chengdu, China
| | - Guiquan Zhu
- West China Hospital of Stomatology, Sichuan University, 610041, Chengdu, China
| | - Yongqing Zhang
- School of Computer Science, Chengdu University of Information Technology, 610225, Chengdu, China
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17
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Sackerson C, Garcia V, Medina N, Maldonado J, Daly J, Cartwright R. Comparative analysis of the myoglobin gene in whales and humans reveals evolutionary changes in regulatory elements and expression levels. PLoS One 2023; 18:e0284834. [PMID: 37643191 PMCID: PMC10464968 DOI: 10.1371/journal.pone.0284834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 08/15/2023] [Indexed: 08/31/2023] Open
Abstract
Cetacea and other diving mammals have undergone numerous adaptations to their aquatic environment, among them high levels of the oxygen-carrying intracellular hemoprotein myoglobin in skeletal muscles. Hypotheses regarding the mechanisms leading to these high myoglobin levels often invoke the induction of gene expression by exercise, hypoxia, and other physiological gene regulatory pathways. Here we explore an alternative hypothesis: that cetacean myoglobin genes have evolved high levels of transcription driven by the intrinsic developmental mechanisms that drive muscle cell differentiation. We have used luciferase assays in differentiated C2C12 cells to test this hypothesis. Contrary to our hypothesis, we find that the myoglobin gene from the minke whale, Balaenoptera acutorostrata, shows a low level of expression, only about 8% that of humans. This low expression level is broadly shared among cetaceans and artiodactylans. Previous work on regulation of the human gene has identified a core muscle-specific enhancer comprised of two regions, the "AT element" and a C-rich sequence 5' of the AT element termed the "CCAC-box". Analysis of the minke whale gene supports the importance of the AT element, but the minke whale CCAC-box ortholog has little effect. Instead, critical positive input has been identified in a G-rich region 3' of the AT element. Also, a conserved E-box in exon 1 positively affects expression, despite having been assigned a repressive role in the human gene. Last, a novel region 5' of the core enhancer has been identified, which we hypothesize may function as a boundary element. These results illustrate regulatory flexibility during evolution. We discuss the possibility that low transcription levels are actually beneficial, and that evolution of the myoglobin protein toward enhanced stability is a critical factor in the accumulation of high myoglobin levels in adult cetacean muscle tissue.
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Affiliation(s)
- Charles Sackerson
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
| | - Vivian Garcia
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
| | - Nicole Medina
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
| | - Jessica Maldonado
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
| | - John Daly
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
| | - Rachel Cartwright
- Biology Department, California State University Channel Islands, Camarillo, California, United States of America
- The Keiki Kohola Project, Lahaina, Hawaii, United States of America
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18
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Friedman RZ, Ramu A, Lichtarge S, Myers CA, Granas DM, Gause M, Corbo JC, Cohen BA, White MA. Active learning of enhancer and silencer regulatory grammar in photoreceptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554146. [PMID: 37662358 PMCID: PMC10473580 DOI: 10.1101/2023.08.21.554146] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Cis-regulatory elements (CREs) direct gene expression in health and disease, and models that can accurately predict their activities from DNA sequences are crucial for biomedicine. Deep learning represents one emerging strategy to model the regulatory grammar that relates CRE sequence to function. However, these models require training data on a scale that exceeds the number of CREs in the genome. We address this problem using active machine learning to iteratively train models on multiple rounds of synthetic DNA sequences assayed in live mammalian retinas. During each round of training the model actively selects sequence perturbations to assay, thereby efficiently generating informative training data. We iteratively trained a model that predicts the activities of sequences containing binding motifs for the photoreceptor transcription factor Cone-rod homeobox (CRX) using an order of magnitude less training data than current approaches. The model's internal confidence estimates of its predictions are reliable guides for designing sequences with high activity. The model correctly identified critical sequence differences between active and inactive sequences with nearly identical transcription factor binding sites, and revealed order and spacing preferences for combinations of motifs. Our results establish active learning as an effective method to train accurate deep learning models of cis-regulatory function after exhausting naturally occurring training examples in the genome.
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Affiliation(s)
- Ryan Z. Friedman
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Avinash Ramu
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Sara Lichtarge
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Connie A. Myers
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - David M. Granas
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Maria Gause
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Joseph C. Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Barak A. Cohen
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
| | - Michael A. White
- The Edison Family Center for Genome Sciences & Systems Biology, Washington University School of Medicine, Saint Louis, MO, 63110
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO, 63110
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19
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Kyrchanova O, Ibragimov A, Postika N, Georgiev P, Schedl P. Boundary bypass activity in the abdominal-B region of the Drosophila bithorax complex is position dependent and regulated. Open Biol 2023; 13:230035. [PMID: 37582404 PMCID: PMC10427195 DOI: 10.1098/rsob.230035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 07/17/2023] [Indexed: 08/17/2023] Open
Abstract
Expression of Abdominal-B (Abd-B) in abdominal segments A5-A8 is controlled by four regulatory domains, iab-5-iab-8. Each domain has an initiator element (which sets the activity state), elements that maintain this state and tissue-specific enhancers. To ensure their functional autonomy, each domain is bracketed by boundary elements (Mcp, Fab-7, Fab-7 and Fab-8). In addition to blocking crosstalk between adjacent regulatory domains, the Fab boundaries must also have bypass activity so the relevant regulatory domains can 'jump over' intervening boundaries and activate the Abd-B promoter. In the studies reported here we have investigated the parameters governing bypass activity. We find that the bypass elements in the Fab-7 and Fab-8 boundaries must be located in the regulatory domain that is responsible for driving Abd-B expression. We suggest that bypass activity may also be subject to regulation.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Airat Ibragimov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
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20
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Kyrchanova O, Ibragimov A, Postika N, Georgiev P, Schedl P. Boundary Bypass Activity in the Abdominal-B Region of the Drosophila Bithorax Complex is Position Dependent and Regulated. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543971. [PMID: 37333165 PMCID: PMC10274778 DOI: 10.1101/2023.06.06.543971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Expression of Abdominal-B ( Abd-B ) in abdominal segments A5 - A8 is controlled by four regulatory domains, iab-5 - iab-8 . Each domain has an initiator element (which sets the activity state), elements that maintain this state and tissue-specific enhancers. To ensure their functional autonomy, each domain is bracketed by boundary elements ( Mcp , Fab-7 , Fab-7 and Fab-8 ). In addition to blocking crosstalk between adjacent regulatory domains, the Fab boundaries must also have bypass activity so the relevant regulatory domains can "jump over" intervening boundaries and activate the Abd-B promoter. In the studies reported here we have investigated the parameters governing bypass activity. We find that the bypass elements in the Fab-7 and Fab-8 boundaries must be located in the regulatory domain that is responsible for driving Abd-B expression. We suggest that bypass activity may also be subject to regulation. Summary Statement Boundaries separating Abd-B regulatory domains block crosstalk between domains and mediate their interactions with Abd-B . The latter function is location but not orientation dependent.
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Affiliation(s)
- Olga Kyrchanova
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Airat Ibragimov
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Institute of Gene Biology, Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Nikolay Postika
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Pavel Georgiev
- Department of the Control of Genetic Processes, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
| | - Paul Schedl
- Laboratory of Gene Expression Regulation in Development, Institute of Gene Biology Russian Academy of Sciences, 34/5 Vavilov St., Moscow 119334, Russia
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
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21
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Mach P, Giorgetti L. Integrative approaches to study enhancer-promoter communication. Curr Opin Genet Dev 2023; 80:102052. [PMID: 37257410 PMCID: PMC10293802 DOI: 10.1016/j.gde.2023.102052] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/21/2023] [Accepted: 04/22/2023] [Indexed: 06/02/2023]
Abstract
The spatiotemporal control of gene expression in complex multicellular organisms relies on noncoding regulatory sequences such as enhancers, which activate transcription of target genes often over large genomic distances. Despite the advances in the identification and characterization of enhancers, the principles and mechanisms by which enhancers select and control their target genes remain largely unknown. Here, we review recent interdisciplinary and quantitative approaches based on emerging techniques that aim to address open questions in the field, notably how regulatory information is encoded in the DNA sequence, how this information is transferred from enhancers to promoters, and how these processes are regulated in time.
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Affiliation(s)
- Pia Mach
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland; University of Basel, Basel, Switzerland. https://twitter.com/@MachPia
| | - Luca Giorgetti
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland.
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22
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Smith GD, Ching WH, Cornejo-Páramo P, Wong ES. Decoding enhancer complexity with machine learning and high-throughput discovery. Genome Biol 2023; 24:116. [PMID: 37173718 PMCID: PMC10176946 DOI: 10.1186/s13059-023-02955-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Enhancers are genomic DNA elements controlling spatiotemporal gene expression. Their flexible organization and functional redundancies make deciphering their sequence-function relationships challenging. This article provides an overview of the current understanding of enhancer organization and evolution, with an emphasis on factors that influence these relationships. Technological advancements, particularly in machine learning and synthetic biology, are discussed in light of how they provide new ways to understand this complexity. Exciting opportunities lie ahead as we continue to unravel the intricacies of enhancer function.
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Affiliation(s)
- Gabrielle D Smith
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, NSW, Australia
| | - Wan Hern Ching
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, Australia
| | - Paola Cornejo-Páramo
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, NSW, Australia
| | - Emily S Wong
- Victor Chang Cardiac Research Institute, 405 Liverpool Street, Darlinghurst, NSW, Australia.
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Kensington, NSW, Australia.
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23
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Ji L, Shi Y, Bian Q. Comparative genomics analyses reveal sequence determinants underlying interspecies variations in injury-responsive enhancers. BMC Genomics 2023; 24:177. [PMID: 37020217 PMCID: PMC10077677 DOI: 10.1186/s12864-023-09283-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND Injury induces profound transcriptional remodeling events, which could lead to only wound healing, partial tissue repair, or perfect regeneration in different species. Injury-responsive enhancers (IREs) are cis-regulatory elements activated in response to injury signals, and have been demonstrated to promote tissue regeneration in some organisms such as zebrafish and flies. However, the functional significances of IREs in mammals remain elusive. Moreover, whether the transcriptional responses elicited by IREs upon injury are conserved or specialized in different species, and what sequence features may underlie the functional variations of IREs have not been elucidated. RESULTS We identified a set of IREs that are activated in both regenerative and non-regenerative neonatal mouse hearts upon myocardial ischemia-induced damage by integrative epigenomic and transcriptomic analyses. Motif enrichment analysis showed that AP-1 and ETS transcription factor binding motifs are significantly enriched in both zebrafish and mouse IREs. However, the IRE-associated genes vary considerably between the two species. We further found that the IRE-related sequences in zebrafish and mice diverge greatly, with the loss of IRE inducibility accompanied by a reduction in AP-1 and ETS motif frequencies. The functional turnover of IREs between zebrafish and mice is correlated with changes in transcriptional responses of the IRE-associated genes upon injury. Using mouse cardiomyocytes as a model, we demonstrated that the reduction in AP-1 or ETS motif frequency attenuates the activation of IREs in response to hypoxia-induced damage. CONCLUSIONS By performing comparative genomics analyses on IREs, we demonstrated that inter-species variations in AP-1 and ETS motifs may play an important role in defining the functions of enhancers during injury response. Our findings provide important insights for understanding the molecular mechanisms of transcriptional remodeling in response to injury across species.
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Affiliation(s)
- Luzhang Ji
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Yuanyuan Shi
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China
| | - Qian Bian
- Shanghai Institute of Precision Medicine, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China.
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24
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Moeckel C, Zaravinos A, Georgakopoulos-Soares I. Strand Asymmetries Across Genomic Processes. Comput Struct Biotechnol J 2023; 21:2036-2047. [PMID: 36968020 PMCID: PMC10030826 DOI: 10.1016/j.csbj.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/08/2023] [Accepted: 03/08/2023] [Indexed: 03/12/2023] Open
Abstract
Across biological systems, a number of genomic processes, including transcription, replication, DNA repair, and transcription factor binding, display intrinsic directionalities. These directionalities are reflected in the asymmetric distribution of nucleotides, motifs, genes, transposon integration sites, and other functional elements across the two complementary strands. Strand asymmetries, including GC skews and mutational biases, have shaped the nucleotide composition of diverse organisms. The investigation of strand asymmetries often serves as a method to understand underlying biological mechanisms, including protein binding preferences, transcription factor interactions, retrotransposition, DNA damage and repair preferences, transcription-replication collisions, and mutagenesis mechanisms. Research into this subject also enables the identification of functional genomic sites, such as replication origins and transcription start sites. Improvements in our ability to detect and quantify DNA strand asymmetries will provide insights into diverse functionalities of the genome, the contribution of different mutational mechanisms in germline and somatic mutagenesis, and our knowledge of genome instability and evolution, which all have significant clinical implications in human disease, including cancer. In this review, we describe key developments that have been made across the field of genomic strand asymmetries, as well as the discovery of associated mechanisms.
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Affiliation(s)
- Camille Moeckel
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Apostolos Zaravinos
- Department of Life Sciences, European University Cyprus, Diogenis Str., 6, Nicosia 2404, Cyprus
- Cancer Genetics, Genomics and Systems Biology laboratory, Basic and Translational Cancer Research Center (BTCRC), Nicosia 1516, Cyprus
- Corresponding author at: Department of Life Sciences, European University Cyprus, Diogenis Str., 6, Nicosia 2404, Cyprus.
| | - Ilias Georgakopoulos-Soares
- Institute for Personalized Medicine, Department of Biochemistry and Molecular Biology, The Pennsylvania State University College of Medicine, Hershey, PA, USA
- Corresponding author.
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25
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Boumpas P, Merabet S, Carnesecchi J. Integrating transcription and splicing into cell fate: Transcription factors on the block. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1752. [PMID: 35899407 DOI: 10.1002/wrna.1752] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/22/2022] [Accepted: 07/01/2022] [Indexed: 11/10/2022]
Abstract
Transcription factors (TFs) are present in all life forms and conserved across great evolutionary distances in eukaryotes. From yeast to complex multicellular organisms, they are pivotal players of cell fate decision by orchestrating gene expression at diverse molecular layers. Notably, TFs fine-tune gene expression by coordinating RNA fate at both the expression and splicing levels. They regulate alternative splicing, an essential mechanism for cell plasticity, allowing the production of many mRNA and protein isoforms in precise cell and tissue contexts. Despite this apparent role in splicing, how TFs integrate transcription and splicing to ultimately orchestrate diverse cell functions and cell fate decisions remains puzzling. We depict substantial studies in various model organisms underlining the key role of TFs in alternative splicing for promoting tissue-specific functions and cell fate. Furthermore, we emphasize recent advances describing the molecular link between the transcriptional and splicing activities of TFs. As TFs can bind both DNA and/or RNA to regulate transcription and splicing, we further discuss their flexibility and compatibility for DNA and RNA substrates. Finally, we propose several models integrating transcription and splicing activities of TFs in the coordination and diversification of cell and tissue identities. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Processing > Splicing Mechanisms.
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Affiliation(s)
- Panagiotis Boumpas
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard-Lyon 1, Lyon, France
| | - Samir Merabet
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard-Lyon 1, Lyon, France
| | - Julie Carnesecchi
- Institut de Génomique Fonctionnelle de Lyon, UMR5242, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, Université Claude Bernard-Lyon 1, Lyon, France
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26
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Reiter F, de Almeida BP, Stark A. Enhancers display constrained sequence flexibility and context-specific modulation of motif function. Genome Res 2023; 33:346-358. [PMID: 36941077 PMCID: PMC10078294 DOI: 10.1101/gr.277246.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 02/14/2023] [Indexed: 03/23/2023]
Abstract
The information about when and where each gene is to be expressed is mainly encoded in the DNA sequence of enhancers, sequence elements that comprise binding sites (motifs) for different transcription factors (TFs). Most of the research on enhancer sequences has been focused on TF motif presence, whereas the enhancer syntax, that is, the flexibility of important motif positions and how the sequence context modulates the activity of TF motifs, remains poorly understood. Here, we explore the rules of enhancer syntax by a two-pronged approach in Drosophila melanogaster S2 cells: we (1) replace important TF motifs by all possible 65,536 eight-nucleotide-long sequences and (2) paste eight important TF motif types into 763 positions within 496 enhancers. These complementary strategies reveal that enhancers display constrained sequence flexibility and the context-specific modulation of motif function. Important motifs can be functionally replaced by hundreds of sequences constituting several distinct motif types, but these are only a fraction of all possible sequences and motif types. Moreover, TF motifs contribute with different intrinsic strengths that are strongly modulated by the enhancer sequence context (the flanking sequence, the presence and diversity of other motif types, and the distance between motifs), such that not all motif types can work in all positions. The context-specific modulation of motif function is also a hallmark of human enhancers, as we demonstrate experimentally. Overall, these two general principles of enhancer sequences are important to understand and predict enhancer function during development, evolution, and in disease.
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Affiliation(s)
- Franziska Reiter
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Bernardo P de Almeida
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030 Vienna, Austria
| | - Alexander Stark
- Research Institute of Molecular Pathology, Vienna BioCenter, Campus-Vienna-BioCenter 1, 1030 Vienna, Austria;
- Medical University of Vienna, Vienna BioCenter, 1030 Vienna, Austria
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27
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Song BP, Ragsac MF, Tellez K, Jindal GA, Grudzien JL, Le SH, Farley EK. Diverse logics and grammar encode notochord enhancers. Cell Rep 2023; 42:112052. [PMID: 36729834 PMCID: PMC10387507 DOI: 10.1016/j.celrep.2023.112052] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 11/07/2022] [Accepted: 01/17/2023] [Indexed: 02/03/2023] Open
Abstract
The notochord is a defining feature of all chordates. The transcription factors Zic and ETS regulate enhancer activity within the notochord. We conduct high-throughput screens of genomic elements within developing Ciona embryos to understand how Zic and ETS sites encode notochord activity. Our screen discovers an enhancer located near Lama, a gene critical for notochord development. Reversing the orientation of an ETS site within this enhancer abolishes expression, indicating that enhancer grammar is critical for notochord activity. Similarly organized clusters of Zic and ETS sites occur within mouse and human Lama1 introns. Within a Brachyury (Bra) enhancer, FoxA and Bra, in combination with Zic and ETS binding sites, are necessary and sufficient for notochord expression. This binding site logic also occurs within other Ciona and vertebrate Bra enhancers. Collectively, this study uncovers the importance of grammar within notochord enhancers and discovers signatures of enhancer logic and grammar conserved across chordates.
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Affiliation(s)
- Benjamin P Song
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Biological Sciences Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Michelle F Ragsac
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA; Bioinformatics and Systems Biology Graduate Program, University of California San Diego, La Jolla, CA 92093, USA
| | - Krissie Tellez
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Granton A Jindal
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jessica L Grudzien
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Sophia H Le
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Emma K Farley
- Department of Medicine, Health Sciences, University of California San Diego, La Jolla, CA 92093, USA; Department of Molecular Biology, Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA.
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28
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Buffry AD, Kittelmann S, McGregor AP. Characterisation of the role and regulation of Ultrabithorax in sculpting fine-scale leg morphology. Front Cell Dev Biol 2023; 11:1119221. [PMID: 36861038 PMCID: PMC9968978 DOI: 10.3389/fcell.2023.1119221] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 01/20/2023] [Indexed: 02/16/2023] Open
Abstract
Hox genes are expressed during embryogenesis and determine the regional identity of animal bodies along the antero-posterior axis. However, they also function post-embryonically to sculpt fine-scale morphology. To better understand how Hox genes are integrated into post-embryonic gene regulatory networks, we further analysed the role and regulation of Ultrabithorax (Ubx) during leg development in Drosophila melanogaster. Ubx regulates several aspects of bristle and trichome patterning on the femurs of the second (T2) and third (T3) leg pairs. We found that repression of trichomes in the proximal posterior region of the T2 femur by Ubx is likely mediated by activation of the expression of microRNA-92a and microRNA-92b by this Hox protein. Furthermore, we identified a novel enhancer of Ubx that recapitulates the temporal and regional activity of this gene in T2 and T3 legs. We then used transcription factor (TF) binding motif analysis in regions of accessible chromatin in T2 leg cells to predict and functionally test TFs that may regulate the Ubx leg enhancer. We also tested the role of the Ubx co-factors Homothorax (Hth) and Extradenticle (Exd) in T2 and T3 femurs. We found several TFs that may act upstream or in concert with Ubx to modulate trichome patterning along the proximo-distal axis of developing femurs and that the repression of trichomes also requires Hth and Exd. Taken together our results provide insights into how Ubx is integrated into a post-embryonic gene regulatory network to determine fine-scale leg morphology.
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Affiliation(s)
- Alexandra D. Buffry
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Sebastian Kittelmann
- Centre for Functional Genomics, Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Alistair P. McGregor
- Department of Biosciences, Durham University, Durham, United Kingdom,*Correspondence: Alistair P. McGregor,
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29
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Galupa R, Alvarez-Canales G, Borst NO, Fuqua T, Gandara L, Misunou N, Richter K, Alves MRP, Karumbi E, Perkins ML, Kocijan T, Rushlow CA, Crocker J. Enhancer architecture and chromatin accessibility constrain phenotypic space during Drosophila development. Dev Cell 2023; 58:51-62.e4. [PMID: 36626871 PMCID: PMC9860173 DOI: 10.1016/j.devcel.2022.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/18/2022] [Accepted: 12/07/2022] [Indexed: 01/11/2023]
Abstract
Developmental enhancers bind transcription factors and dictate patterns of gene expression during development. Their molecular evolution can underlie phenotypical evolution, but the contributions of the evolutionary pathways involved remain little understood. Here, using mutation libraries in Drosophila melanogaster embryos, we observed that most point mutations in developmental enhancers led to changes in gene expression levels but rarely resulted in novel expression outside of the native pattern. In contrast, random sequences, often acting as developmental enhancers, drove expression across a range of cell types; random sequences including motifs for transcription factors with pioneer activity acted as enhancers even more frequently. Our findings suggest that the phenotypic landscapes of developmental enhancers are constrained by enhancer architecture and chromatin accessibility. We propose that the evolution of existing enhancers is limited in its capacity to generate novel phenotypes, whereas the activity of de novo elements is a primary source of phenotypic novelty.
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Affiliation(s)
- Rafael Galupa
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
| | | | | | - Timothy Fuqua
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Lautaro Gandara
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Natalia Misunou
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Kerstin Richter
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Esther Karumbi
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Tin Kocijan
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Justin Crocker
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
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30
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Begeman IJ, Emery B, Kurth A, Kang J. Regeneration and developmental enhancers are differentially compatible with minimal promoters. Dev Biol 2022; 492:47-58. [PMID: 36167150 PMCID: PMC10211259 DOI: 10.1016/j.ydbio.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 12/01/2022]
Abstract
Enhancers and promoters are cis-regulatory elements that control gene expression. Enhancers are activated in a cell type-, tissue-, and condition-specific manner to stimulate promoter function and transcription. Zebrafish have emerged as a powerful animal model for examining the activities of enhancers derived from various species through transgenic enhancer assays, in which an enhancer is coupled with a minimal promoter. However, the efficiency of minimal promoters and their compatibility with multiple developmental and regeneration enhancers have not been systematically tested in zebrafish. Thus, we assessed the efficiency of six minimal promoters and comprehensively interrogated the compatibility of the promoters with developmental and regeneration enhancers. We found that the fos minimal promoter and Drosophila synthetic core promoter (DSCP) yielded high rates of leaky expression that may complicate the interpretation of enhancer assays. Notably, the adenovirus E1b promoter, the zebrafish lepb 0.8-kb (P0.8) and lepb 2-kb (P2) promoters, and a new zebrafish synthetic promoter (ZSP) that combines elements of the E1b and P0.8 promoters drove little or no ectopic expression, making them suitable for transgenic assays. We also found significant differences in compatibility among specific combinations of promoters and enhancers, indicating the importance of promoters as key regulatory elements determining the specificity of gene expression. Our study provides guidelines for transgenic enhancer assays in zebrafish to aid in the discovery of functional enhancers regulating development and regeneration.
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Affiliation(s)
- Ian J Begeman
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Benjamin Emery
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Andrew Kurth
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Junsu Kang
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA; UW Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53705, USA.
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31
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Wang H, Bai C. The accurate expression pattern of acute phase marker C-reactive protein depends on the distal enhancer. CHINESE SCIENCE BULLETIN-CHINESE 2022. [DOI: 10.1360/tb-2022-0962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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32
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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33
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Nair SJ, Suter T, Wang S, Yang L, Yang F, Rosenfeld MG. Transcriptional enhancers at 40: evolution of a viral DNA element to nuclear architectural structures. Trends Genet 2022; 38:1019-1047. [PMID: 35811173 PMCID: PMC9474616 DOI: 10.1016/j.tig.2022.05.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/05/2022] [Accepted: 05/31/2022] [Indexed: 02/08/2023]
Abstract
Gene regulation by transcriptional enhancers is the dominant mechanism driving cell type- and signal-specific transcriptional diversity in metazoans. However, over four decades since the original discovery, how enhancers operate in the nuclear space remains largely enigmatic. Recent multidisciplinary efforts combining real-time imaging, genome sequencing, and biophysical strategies provide insightful but conflicting models of enhancer-mediated gene control. Here, we review the discovery and progress in enhancer biology, emphasizing the recent findings that acutely activated enhancers assemble regulatory machinery as mesoscale architectural structures with distinct physical properties. These findings help formulate novel models that explain several mysterious features of the assembly of transcriptional enhancers and the mechanisms of spatial control of gene expression.
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Affiliation(s)
- Sreejith J Nair
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC 20057, USA.
| | - Tom Suter
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan Wang
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Cellular and Molecular Medicine Graduate Program, University of California, San Diego, La Jolla, CA 92093, USA
| | - Lu Yang
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Feng Yang
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael G Rosenfeld
- Howard Hughes Medical Institute, Department and School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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34
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Zhao Y, Vartak SV, Conte A, Wang X, Garcia DA, Stevens E, Kyoung Jung S, Kieffer-Kwon KR, Vian L, Stodola T, Moris F, Chopp L, Preite S, Schwartzberg PL, Kulinski JM, Olivera A, Harly C, Bhandoola A, Heuston EF, Bodine DM, Urrutia R, Upadhyaya A, Weirauch MT, Hager G, Casellas R. "Stripe" transcription factors provide accessibility to co-binding partners in mammalian genomes. Mol Cell 2022; 82:3398-3411.e11. [PMID: 35863348 PMCID: PMC9481673 DOI: 10.1016/j.molcel.2022.06.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 04/06/2022] [Accepted: 06/22/2022] [Indexed: 10/17/2022]
Abstract
Regulatory elements activate promoters by recruiting transcription factors (TFs) to specific motifs. Notably, TF-DNA interactions often depend on cooperativity with colocalized partners, suggesting an underlying cis-regulatory syntax. To explore TF cooperativity in mammals, we analyze ∼500 mouse and human primary cells by combining an atlas of TF motifs, footprints, ChIP-seq, transcriptomes, and accessibility. We uncover two TF groups that colocalize with most expressed factors, forming stripes in hierarchical clustering maps. The first group includes lineage-determining factors that occupy DNA elements broadly, consistent with their key role in tissue-specific transcription. The second one, dubbed universal stripe factors (USFs), comprises ∼30 SP, KLF, EGR, and ZBTB family members that recognize overlapping GC-rich sequences in all tissues analyzed. Knockouts and single-molecule tracking reveal that USFs impart accessibility to colocalized partners and increase their residence time. Mammalian cells have thus evolved a TF superfamily with overlapping DNA binding that facilitate chromatin accessibility.
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Affiliation(s)
- Yongbing Zhao
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA.
| | - Supriya V Vartak
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | - Andrea Conte
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | - Xiang Wang
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | - David A Garcia
- Laboratory of Receptor Biology and Gene Expression, NCI, NIH, Bethesda, MD 20893, USA; Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Evan Stevens
- Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | - Seol Kyoung Jung
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | | | - Laura Vian
- Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA
| | - Timothy Stodola
- Genomic Sciences and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Francisco Moris
- EntreChem S.L., Vivero Ciencias de la Salud, 33011 Oviedo, Spain
| | - Laura Chopp
- Laboratory of Immune Cell Biology, NCI, NIH, Bethesda, MD 20892, USA
| | - Silvia Preite
- Laboratory of Immune System Biology, NIAID, NIH, Bethesda, MD 20892, USA
| | | | - Joseph M Kulinski
- Mast cell Biology Section, Laboratory of Allergic Diseases, NIAID, NIH, Bethesda, MD 20892, USA
| | - Ana Olivera
- Mast cell Biology Section, Laboratory of Allergic Diseases, NIAID, NIH, Bethesda, MD 20892, USA
| | - Christelle Harly
- Laboratory of Genome Integrity, NCI, NIH, Bethesda, MD 20892, USA
| | | | | | - David M Bodine
- Genetics and Molecular Biology Branch, NHGRI, NIH, Bethesda, MD 20892, USA
| | - Raul Urrutia
- Genomic Sciences and Precision Medicine Center (GSPMC), Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Arpita Upadhyaya
- Department of Physics, University of Maryland, College Park, MD 20742, USA
| | - Matthew T Weirauch
- Divisions of Biomedical Informatics and Developmental Biology, Center for Autoimmune Genomics and Etiology (CAGE), Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Gordon Hager
- Laboratory of Receptor Biology and Gene Expression, NCI, NIH, Bethesda, MD 20893, USA
| | - Rafael Casellas
- The NIH Regulome Project, National Institutes of Health, Bethesda, MD 20892, USA; Lymphocyte Nuclear Biology, NIAMS-NCI, NIH, Bethesda, MD 20892, USA.
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35
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Downes DJ, Hughes JR. Natural and Experimental Rewiring of Gene Regulatory Regions. Annu Rev Genomics Hum Genet 2022; 23:73-97. [PMID: 35472292 DOI: 10.1146/annurev-genom-112921-010715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The successful development and ongoing functioning of complex organisms depend on the faithful execution of the genetic code. A critical step in this process is the correct spatial and temporal expression of genes. The highly orchestrated transcription of genes is controlled primarily by cis-regulatory elements: promoters, enhancers, and insulators. The medical importance of this key biological process can be seen by the frequency with which mutations and inherited variants that alter cis-regulatory elements lead to monogenic and complex diseases and cancer. Here, we provide an overview of the methods available to characterize and perturb gene regulatory circuits. We then highlight mechanisms through which regulatory rewiring contributes to disease, and conclude with a perspective on how our understanding of gene regulation can be used to improve human health.
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Affiliation(s)
- Damien J Downes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom;
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom;
- MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom;
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36
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Yang MG, Ling E, Cowley CJ, Greenberg ME, Vierbuchen T. Characterization of sequence determinants of enhancer function using natural genetic variation. eLife 2022; 11:76500. [PMID: 36043696 PMCID: PMC9662815 DOI: 10.7554/elife.76500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 08/30/2022] [Indexed: 02/04/2023] Open
Abstract
Sequence variation in enhancers that control cell-type-specific gene transcription contributes significantly to phenotypic variation within human populations. However, it remains difficult to predict precisely the effect of any given sequence variant on enhancer function due to the complexity of DNA sequence motifs that determine transcription factor (TF) binding to enhancers in their native genomic context. Using F1-hybrid cells derived from crosses between distantly related inbred strains of mice, we identified thousands of enhancers with allele-specific TF binding and/or activity. We find that genetic variants located within the central region of enhancers are most likely to alter TF binding and enhancer activity. We observe that the AP-1 family of TFs (Fos/Jun) are frequently required for binding of TEAD TFs and for enhancer function. However, many sequence variants outside of core motifs for AP-1 and TEAD also impact enhancer function, including sequences flanking core TF motifs and AP-1 half sites. Taken together, these data represent one of the most comprehensive assessments of allele-specific TF binding and enhancer function to date and reveal how sequence changes at enhancers alter their function across evolutionary timescales.
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Affiliation(s)
- Marty G Yang
- Department of Neurobiology, Harvard Medical School, Boston, United States.,Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Emi Ling
- Department of Neurobiology, Harvard Medical School, Boston, United States
| | | | | | - Thomas Vierbuchen
- Developmental Biology Program, Sloan Kettering Institute for Cancer Research, New York, United States.,Center for Stem Cell Biology, Sloan Kettering Institute for Cancer Research, New York, United States
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37
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Rao S, Han AL, Zukowski A, Kopin E, Sartorius CA, Kabos P, Ramachandran S. Transcription factor-nucleosome dynamics from plasma cfDNA identifies ER-driven states in breast cancer. SCIENCE ADVANCES 2022; 8:eabm4358. [PMID: 36001652 PMCID: PMC9401618 DOI: 10.1126/sciadv.abm4358] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 07/12/2022] [Indexed: 06/09/2023]
Abstract
Genome-wide binding profiles of estrogen receptor (ER) and FOXA1 reflect cancer state in ER+ breast cancer. However, routine profiling of tumor transcription factor (TF) binding is impractical in the clinic. Here, we show that plasma cell-free DNA (cfDNA) contains high-resolution ER and FOXA1 tumor binding profiles for breast cancer. Enrichment of TF footprints in plasma reflects the binding strength of the TF in originating tissue. We defined pure in vivo tumor TF signatures in plasma using ER+ breast cancer xenografts, which can distinguish xenografts with distinct ER states. Furthermore, state-specific ER-binding signatures can partition human breast tumors into groups with significantly different ER expression and mortality. Last, TF footprints in human plasma samples can identify the presence of ER+ breast cancer. Thus, plasma TF footprints enable minimally invasive mapping of the regulatory landscape of breast cancer in humans and open vast possibilities for clinical applications across multiple tumor types.
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Affiliation(s)
- Satyanarayan Rao
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA
| | - Amy L. Han
- Department of Medicine/Division of Medical Oncology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Alexis Zukowski
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA
| | - Etana Kopin
- Department of Medicine/Division of Medical Oncology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Carol A. Sartorius
- Department of Pathology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Peter Kabos
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA
- Department of Medicine/Division of Medical Oncology, University of Colorado School of Medicine, Aurora, CO, USA
- University of Colorado Cancer Center, Aurora, CO, USA
| | - Srinivas Ramachandran
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, USA
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, CO, USA
- University of Colorado Cancer Center, Aurora, CO, USA
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38
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Wang J, Wang A, Tian K, Hua X, Zhang B, Zheng Y, Kong X, Li W, Xu L, Wang J, Li Z, Liu Y, Zhou Y. A Ctnnb1 enhancer regulates neocortical neurogenesis by controlling the abundance of intermediate progenitors. Cell Discov 2022; 8:74. [PMID: 35915089 PMCID: PMC9343459 DOI: 10.1038/s41421-022-00421-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 05/05/2022] [Indexed: 11/09/2022] Open
Abstract
β-catenin-dependent canonical Wnt signaling plays a plethora of roles in neocortex (Ncx) development, but its function in regulating the abundance of intermediate progenitors (IPs) is elusive. Here we identified neCtnnb1, an evolutionarily conserved cis-regulatory element with typical enhancer features in developing Ncx. neCtnnb1 locates 55 kilobase upstream of and spatially close to the promoter of Ctnnb1, the gene encoding β-catenin. CRISPR/Cas9-mediated activation or interference of the neCtnnb1 locus enhanced or inhibited transcription of Ctnnb1. neCtnnb1 drove transcription predominantly in the subventricular zone of developing Ncx. Knock-out of neCtnnb1 in mice resulted in compromised expression of Ctnnb1 and the Wnt reporter in developing Ncx. Importantly, knock-out of neCtnnb1 lead to reduced production and transit-amplification of IPs, which subsequently generated fewer upper-layer Ncx projection neurons (PNs). In contrast, enhancing the canonical Wnt signaling by stabilizing β-catenin in neCtnnb1-active cells promoted the production of IPs and upper-layer Ncx PNs. ASH2L was identified as the key trans-acting factor that associates with neCtnnb1 and Ctnnb1’s promoter to maintain Ctnnb1’s transcription in both mouse and human Ncx progenitors. These findings advance understanding of transcriptional regulation of Ctnnb1, and provide insights into mechanisms underlying Ncx expansion during development.
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Affiliation(s)
- Junbao Wang
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Andi Wang
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Kuan Tian
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Xiaojiao Hua
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Bo Zhang
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Yue Zheng
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Xiangfei Kong
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Wei Li
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Lichao Xu
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Juan Wang
- Department of Neurology, Wuhan Central Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhiqiang Li
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China
| | - Ying Liu
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China.
| | - Yan Zhou
- Department of Neurosurgery, Zhongnan Hospital of Wuhan University; Frontier Science Center for Immunology and Metabolism, Medical Research Institute at School of Medicine; The RNA Institute, College of Life Sciences; Wuhan University, Wuhan, Hubei, China.
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39
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Bentsen M, Heger V, Schultheis H, Kuenne C, Looso M. TF-COMB - discovering grammar of transcription factor binding sites. Comput Struct Biotechnol J 2022; 20:4040-4051. [PMID: 35983231 PMCID: PMC9358416 DOI: 10.1016/j.csbj.2022.07.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/12/2022] [Indexed: 02/07/2023] Open
Abstract
Cooperativity between transcription factors is important to regulate target gene expression. In particular, the binding grammar of TFs in relation to each other, as well as in the context of other genomic elements, is crucial for TF functionality. However, tools to easily uncover co-occurrence between DNA-binding proteins, and investigate the regulatory modules of TFs, are limited. Here we present TF-COMB (Transcription Factor Co-Occurrence using Market Basket analysis) - a tool to investigate co-occurring TFs and binding grammar within regulatory regions. We found that TF-COMB can accurately identify known co-occurring TFs from ChIP-seq data, as well as uncover preferential localization to other genomic elements. With the use of ATAC-seq footprinting and TF motif locations, we found that TFs exhibit both preferred orientation and distance in relation to each other, and that these are biologically significant. Finally, we extended the analysis to not only investigate individual TF pairs, but also TF pairs in the context of networks, which enabled the investigation of TF complexes and TF hubs. In conclusion, TF-COMB is a flexible tool to investigate various aspects of TF binding grammar.
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Affiliation(s)
- Mette Bentsen
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Vanessa Heger
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Hendrik Schultheis
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Carsten Kuenne
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Mario Looso
- Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Cardio-Pulmonary Institute (CPI), Bad Nauheim, Germany
- Corresponding author at: Bioinformatics Core Unit (BCU), Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany.
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40
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Wang MY, Zhang CM, Zhou HH, Ge ZB, Su CC, Lou ZH, Zhang XY, Xu TT, Li SY, Zhu L, Zhou YL, Wu Y, Ji SR. Identification of a distal enhancer that determines the expression pattern of acute phase marker C-reactive protein. J Biol Chem 2022; 298:102160. [PMID: 35724961 PMCID: PMC9287136 DOI: 10.1016/j.jbc.2022.102160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/09/2022] [Accepted: 06/11/2022] [Indexed: 11/18/2022] Open
Abstract
C-reactive protein (CRP) is a major acute phase protein and inflammatory marker, the expression of which is largely liver specific and highly inducible. Enhancers are regulatory elements critical for the precise activation of gene expression, yet the contributions of enhancers to the expression pattern of CRP have not been well defined. Here, we identify a constitutively active enhancer (E1) located 37.7 kb upstream of the promoter of human CRP in hepatocytes. By using chromatin immunoprecipitation, luciferase reporter assay, in situ genetic manipulation, CRISPRi, and CRISPRa, we show that E1 is enriched in binding sites for transcription factors STAT3 and C/EBP-β and is essential for the full induction of human CRP during the acute phase. Moreover, we demonstrate that E1 orchestrates with the promoter of CRP to determine its varied expression across tissues and species through surveying activities of E1-promoter hybrids and the associated epigenetic modifications. These results thus suggest an intriguing mode of molecular evolution wherein expression-changing mutations in distal regulatory elements initiate subsequent functional selection involving coupling among distal/proximal regulatory mutations and activity-changing coding mutations.
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Affiliation(s)
- Ming-Yu Wang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Chun-Miao Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Hai-Hong Zhou
- Gansu Provincial Cancer Hospital, Lanzhou 730050, P.R. China
| | - Zhong-Bo Ge
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Chen-Chen Su
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Zi-Hao Lou
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Xin-Yun Zhang
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Tao-Tao Xu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Si-Yi Li
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China
| | - Li Zhu
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China; Electron Microscopy Centre of Lanzhou University, Lanzhou 730000, China
| | - Ya-Li Zhou
- Cuiying Biomedical Research Center, Lanzhou University Second Hospital, Lanzhou, 730030, China
| | - Yi Wu
- MOE Key Laboratory of Environment and Genes Related to Diseases, School of Basic Medical Sciences, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China; Key Laboratory of Precision Medicine to Pediatric Diseases of Shaanxi Province, Xi'an Children's Hospital, Xi'an Jiaotong University, Xi'an, P.R. China.
| | - Shang-Rong Ji
- MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, P.R. China.
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41
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Lawler AJ, Ramamurthy E, Brown AR, Shin N, Kim Y, Toong N, Kaplow IM, Wirthlin M, Zhang X, Phan BN, Fox GA, Wade K, He J, Ozturk BE, Byrne LC, Stauffer WR, Fish KN, Pfenning AR. Machine learning sequence prioritization for cell type-specific enhancer design. eLife 2022; 11:69571. [PMID: 35576146 PMCID: PMC9110026 DOI: 10.7554/elife.69571] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 04/25/2022] [Indexed: 11/22/2022] Open
Abstract
Recent discoveries of extreme cellular diversity in the brain warrant rapid development of technologies to access specific cell populations within heterogeneous tissue. Available approaches for engineering-targeted technologies for new neuron subtypes are low yield, involving intensive transgenic strain or virus screening. Here, we present Specific Nuclear-Anchored Independent Labeling (SNAIL), an improved virus-based strategy for cell labeling and nuclear isolation from heterogeneous tissue. SNAIL works by leveraging machine learning and other computational approaches to identify DNA sequence features that confer cell type-specific gene activation and then make a probe that drives an affinity purification-compatible reporter gene. As a proof of concept, we designed and validated two novel SNAIL probes that target parvalbumin-expressing (PV+) neurons. Nuclear isolation using SNAIL in wild-type mice is sufficient to capture characteristic open chromatin features of PV+ neurons in the cortex, striatum, and external globus pallidus. The SNAIL framework also has high utility for multispecies cell probe engineering; expression from a mouse PV+ SNAIL enhancer sequence was enriched in PV+ neurons of the macaque cortex. Expansion of this technology has broad applications in cell type-specific observation, manipulation, and therapeutics across species and disease models.
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Affiliation(s)
- Alyssa J Lawler
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Biological Sciences Department, Mellon College of Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Easwaran Ramamurthy
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Ashley R Brown
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Naomi Shin
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Yeonju Kim
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Noelle Toong
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Irene M Kaplow
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Morgan Wirthlin
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Xiaoyu Zhang
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - BaDoi N Phan
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States.,Medical Scientist Training Program, University of Pittsburgh, Pittsburgh, United States
| | - Grant A Fox
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
| | - Kirsten Wade
- Department of Psychiatry, Translational Neuroscience Program, University of Pittsburgh, Pittsburgh, United States
| | - Jing He
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Systems Neuroscience Center, Brain Institute, Center for Neuroscience, Center for the Neural Basis of Cognition, Pittsburgh, United States
| | - Bilge Esin Ozturk
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States
| | - Leah C Byrne
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Department of Ophthalmology, University of Pittsburgh, Pittsburgh, United States.,Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, United States
| | - William R Stauffer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
| | - Kenneth N Fish
- Department of Psychiatry, Translational Neuroscience Program, University of Pittsburgh, Pittsburgh, United States
| | - Andreas R Pfenning
- Computational Biology Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, United States.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, United States
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42
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DeepSTARR predicts enhancer activity from DNA sequence and enables the de novo design of synthetic enhancers. Nat Genet 2022; 54:613-624. [PMID: 35551305 DOI: 10.1038/s41588-022-01048-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 03/08/2022] [Indexed: 02/06/2023]
Abstract
Enhancer sequences control gene expression and comprise binding sites (motifs) for different transcription factors (TFs). Despite extensive genetic and computational studies, the relationship between DNA sequence and regulatory activity is poorly understood, and de novo enhancer design has been challenging. Here, we built a deep-learning model, DeepSTARR, to quantitatively predict the activities of thousands of developmental and housekeeping enhancers directly from DNA sequence in Drosophila melanogaster S2 cells. The model learned relevant TF motifs and higher-order syntax rules, including functionally nonequivalent instances of the same TF motif that are determined by motif-flanking sequence and intermotif distances. We validated these rules experimentally and demonstrated that they can be generalized to humans by testing more than 40,000 wildtype and mutant Drosophila and human enhancers. Finally, we designed and functionally validated synthetic enhancers with desired activities de novo.
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43
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McDonald JMC, Reed RD. Patterns of selection across gene regulatory networks. Semin Cell Dev Biol 2022; 145:60-67. [PMID: 35474149 DOI: 10.1016/j.semcdb.2022.03.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 01/31/2022] [Accepted: 03/23/2022] [Indexed: 12/29/2022]
Abstract
Gene regulatory networks (GRNs) are the core engine of organismal development. If we would like to understand the origin and diversification of phenotypes, it is necessary to consider the structure of GRNs in order to reconstruct the links between genetic mutations and phenotypic change. Much of the progress in evolutionary developmental biology, however, has occurred without a nuanced consideration of the evolution of functional relationships between genes, especially in the context of their broader network interactions. Characterizing and comparing GRNs across traits and species in a more detailed way will allow us to determine how network position influences what genes drive adaptive evolution. In this perspective paper, we consider the architecture of developmental GRNs and how positive selection strength may vary across a GRN. We then propose several testable models for these patterns of selection and experimental approaches to test these models.
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Affiliation(s)
- Jeanne M C McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
| | - Robert D Reed
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States.
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44
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Chua EHZ, Yasar S, Harmston N. The importance of considering regulatory domains in genome-wide analyses - the nearest gene is often wrong! Biol Open 2022; 11:274931. [PMID: 35377406 PMCID: PMC9002814 DOI: 10.1242/bio.059091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The expression of a large number of genes is regulated by regulatory elements that are located far away from their promoters. Identifying which gene is the target of a specific regulatory element or is affected by a non-coding mutation is often accomplished by assigning these regions to the nearest gene in the genome. However, this heuristic ignores key features of genome organisation and gene regulation; in that the genome is partitioned into regulatory domains, which at some loci directly coincide with the span of topologically associated domains (TADs), and that genes are regulated by enhancers located throughout these regions, even across intervening genes. In this review, we examine the results from genome-wide studies using chromosome conformation capture technologies and from those dissecting individual gene regulatory domains, to highlight that the phenomenon of enhancer skipping is pervasive and affects multiple types of genes. We discuss how simply assigning a genomic region of interest to its nearest gene is problematic and often leads to incorrect predictions and highlight that where possible information on both the conservation and topological organisation of the genome should be used to generate better hypotheses. The article has an associated Future Leader to Watch interview. Summary: Identifying which gene is the target of an enhancer is often accomplished by assigning it to the nearest gene, here we discuss how this heuristic can lead to incorrect predictions.
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Affiliation(s)
| | - Samen Yasar
- Science Division, Yale-NUS College, Singapore 138527, Singapore
| | - Nathan Harmston
- Science Division, Yale-NUS College, Singapore 138527, Singapore.,Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore 169857, Singapore
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45
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Kaplow IM, Schäffer DE, Wirthlin ME, Lawler AJ, Brown AR, Kleyman M, Pfenning AR. Inferring mammalian tissue-specific regulatory conservation by predicting tissue-specific differences in open chromatin. BMC Genomics 2022; 23:291. [PMID: 35410163 PMCID: PMC8996547 DOI: 10.1186/s12864-022-08450-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 03/07/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Evolutionary conservation is an invaluable tool for inferring functional significance in the genome, including regions that are crucial across many species and those that have undergone convergent evolution. Computational methods to test for sequence conservation are dominated by algorithms that examine the ability of one or more nucleotides to align across large evolutionary distances. While these nucleotide alignment-based approaches have proven powerful for protein-coding genes and some non-coding elements, they fail to capture conservation of many enhancers, distal regulatory elements that control spatial and temporal patterns of gene expression. The function of enhancers is governed by a complex, often tissue- and cell type-specific code that links combinations of transcription factor binding sites and other regulation-related sequence patterns to regulatory activity. Thus, function of orthologous enhancer regions can be conserved across large evolutionary distances, even when nucleotide turnover is high. RESULTS We present a new machine learning-based approach for evaluating enhancer conservation that leverages the combinatorial sequence code of enhancer activity rather than relying on the alignment of individual nucleotides. We first train a convolutional neural network model that can predict tissue-specific open chromatin, a proxy for enhancer activity, across mammals. Next, we apply that model to distinguish instances where the genome sequence would predict conserved function versus a loss of regulatory activity in that tissue. We present criteria for systematically evaluating model performance for this task and use them to demonstrate that our models accurately predict tissue-specific conservation and divergence in open chromatin between primate and rodent species, vastly out-performing leading nucleotide alignment-based approaches. We then apply our models to predict open chromatin at orthologs of brain and liver open chromatin regions across hundreds of mammals and find that brain enhancers associated with neuron activity have a stronger tendency than the general population to have predicted lineage-specific open chromatin. CONCLUSION The framework presented here provides a mechanism to annotate tissue-specific regulatory function across hundreds of genomes and to study enhancer evolution using predicted regulatory differences rather than nucleotide-level conservation measurements.
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Affiliation(s)
- Irene M Kaplow
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA. .,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA.
| | - Daniel E Schäffer
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Morgan E Wirthlin
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Alyssa J Lawler
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA.,Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Ashley R Brown
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Michael Kleyman
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA.,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Andreas R Pfenning
- Department of Computational Biology, Carnegie Mellon University, Pittsburgh, PA, USA. .,Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, USA. .,Department of Biology, Carnegie Mellon University, Pittsburgh, PA, USA.
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46
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VandenBosch LS, Luu K, Timms AE, Challam S, Wu Y, Lee AY, Cherry TJ. Machine Learning Prediction of Non-Coding Variant Impact in Human Retinal cis-Regulatory Elements. Transl Vis Sci Technol 2022; 11:16. [PMID: 35435921 PMCID: PMC9034719 DOI: 10.1167/tvst.11.4.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 03/25/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose Prior studies have demonstrated the significance of specific cis-regulatory variants in retinal disease; however, determining the functional impact of regulatory variants remains a major challenge. In this study, we utilized a machine learning approach, trained on epigenomic data from the adult human retina, to systematically quantify the predicted impact of cis-regulatory variants. Methods We used human retinal DNA accessibility data (ATAC-seq) to determine a set of 18.9k high-confidence, putative cis-regulatory elements. Eighty percent of these elements were used to train a machine learning model utilizing a gapped k-mer support vector machine-based approach. In silico saturation mutagenesis and variant scoring was applied to predict the functional impact of all potential single nucleotide variants within cis-regulatory elements. Impact scores were tested in a 20% hold-out dataset and compared to allele population frequency, phylogenetic conservation, transcription factor (TF) binding motifs, and existing massively parallel reporter assay data. Results We generated a model that distinguishes between human retinal regulatory elements and negative test sequences with 95% accuracy. Among a hold-out test set of 3.7k human retinal CREs, all possible single nucleotide variants were scored. Variants with negative impact scores correlated with higher phylogenetic conservation of the reference allele, disruption of predicted TF binding motifs, and massively parallel reporter expression. Conclusions We demonstrated the utility of human retinal epigenomic data to train a machine learning model for the purpose of predicting the impact of non-coding regulatory sequence variants. Our model accurately scored sequences and predicted putative transcription factor binding motifs. This approach has the potential to expedite the characterization of pathogenic non-coding sequence variants in the context of unexplained retinal disease. Translational Relevance This workflow and resulting dataset serve as a promising genomic tool to facilitate the clinical prioritization of functionally disruptive non-coding mutations in the retina.
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Affiliation(s)
- Leah S. VandenBosch
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Kelsey Luu
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Andrew E. Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Shriya Challam
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
| | - Yue Wu
- University of Washington Department of Ophthalmology, Seattle, WA, USA
| | - Aaron Y. Lee
- University of Washington Department of Ophthalmology, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
| | - Timothy J. Cherry
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, WA, USA
- Brotman Baty Institute for Precision Medicine, Seattle, WA, USA
- University of Washington Department of Pediatrics, Seattle, WA, USA
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47
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Balsalobre A, Drouin J. Pioneer factors as master regulators of the epigenome and cell fate. Nat Rev Mol Cell Biol 2022; 23:449-464. [PMID: 35264768 DOI: 10.1038/s41580-022-00464-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2022] [Indexed: 12/23/2022]
Abstract
Pioneer factors are transcription factors with the unique ability to initiate opening of closed chromatin. The stability of cell identity relies on robust mechanisms that maintain the epigenome and chromatin accessibility to transcription factors. Pioneer factors counter these mechanisms to implement new cell fates through binding of DNA target sites in closed chromatin and introduction of active-chromatin histone modifications, primarily at enhancers. As master regulators of enhancer activation, pioneers are thus crucial for the implementation of correct cell fate decisions in development, and as such, they hold tremendous potential for therapy through cellular reprogramming. The power of pioneer factors to reshape the epigenome also presents an Achilles heel, as their misexpression has major pathological consequences, such as in cancer. In this Review, we discuss the emerging mechanisms of pioneer factor functions and their roles in cell fate specification, cellular reprogramming and cancer.
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Affiliation(s)
- Aurelio Balsalobre
- Laboratoire de génétique moléculaire, Institut de recherches cliniques de Montréal, Montreal, QC, Canada
| | - Jacques Drouin
- Laboratoire de génétique moléculaire, Institut de recherches cliniques de Montréal, Montreal, QC, Canada.
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48
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McKenna KZ, Gawne R, Nijhout HF. The genetic control paradigm in biology: What we say, and what we are entitled to mean. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 169-170:89-93. [PMID: 35218858 DOI: 10.1016/j.pbiomolbio.2022.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/27/2022] [Accepted: 02/22/2022] [Indexed: 12/25/2022]
Abstract
We comment on the article by Keith Baverstock (2021) and provide critiques of the concepts of genetic control, genetic blueprint and genetic program.
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Affiliation(s)
- Kenneth Z McKenna
- Department of Biology, University of California, San Diego, United States
| | - Richard Gawne
- Allen Discovery Center at Tufts University, United States
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49
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Snetkova V, Pennacchio LA, Visel A, Dickel DE. Perfect and imperfect views of ultraconserved sequences. Nat Rev Genet 2022; 23:182-194. [PMID: 34764456 PMCID: PMC8858888 DOI: 10.1038/s41576-021-00424-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2021] [Indexed: 12/12/2022]
Abstract
Across the human genome, there are nearly 500 'ultraconserved' elements: regions of at least 200 contiguous nucleotides that are perfectly conserved in both the mouse and rat genomes. Remarkably, the majority of these sequences are non-coding, and many can function as enhancers that activate tissue-specific gene expression during embryonic development. From their first description more than 15 years ago, their extreme conservation has both fascinated and perplexed researchers in genomics and evolutionary biology. The intrigue around ultraconserved elements only grew with the observation that they are dispensable for viability. Here, we review recent progress towards understanding the general importance and the specific functions of ultraconserved sequences in mammalian development and human disease and discuss possible explanations for their extreme conservation.
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Affiliation(s)
- Valentina Snetkova
- Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Len A. Pennacchio
- Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA,Comparative Biochemistry Program, University of California, Berkeley, CA 94720, USA,U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, USA,To whom correspondence should be addressed: L.A.P., ; A.V., ; D.E.D., (lead contact)
| | - Axel Visel
- Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. .,US Department of Energy Joint Genome Institute, Berkeley, CA, USA. .,School of Natural Sciences, University of California, Merced, Merced, CA, USA.
| | - Diane E. Dickel
- Environmental Genomics & Systems Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA,To whom correspondence should be addressed: L.A.P., ; A.V., ; D.E.D., (lead contact)
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50
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Vanaja A, Yella VR. Delineation of the DNA Structural Features of Eukaryotic Core Promoter Classes. ACS OMEGA 2022; 7:5657-5669. [PMID: 35224327 PMCID: PMC8867553 DOI: 10.1021/acsomega.1c04603] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/27/2022] [Indexed: 05/02/2023]
Abstract
The eukaryotic transcription is orchestrated from a chunk of the DNA region stated as the core promoter. Multifarious and punctilious core promoter signals, viz., TATA-box, Inr, BREs, and Pause Button, are associated with a subset of genes and regulate their spatiotemporal expression. However, the core promoter architecture linked with these signals has not been investigated exhaustively for several species. In this study, we attempted to envisage the adaptive binding landscape of the transcription initiation machinery as a function of DNA structure. To this end, we deployed a set of k-mer based DNA structural estimates and regular expression models derived from experiments, molecular dynamic simulations, and theoretical frameworks, and high-throughout promoter data sets retrieved from the eukaryotic promoter database. We categorized protein-coding gene core promoters based on characteristic motifs at precise locations and analyzed the B-DNA structural properties and non-B-DNA structural motifs for 15 different eukaryotic genomes. We observed that Inr, BREd, and no-motif classes display common patterns of DNA sequence and structural environment. TATA-containing, BREu, and Pause Button classes show a deviant behavior with the TATA class displaying varied axial and twisting flexibility while BREu and Pause Button leaned toward G-quadruplex motif enrichment. Intriguingly, DNA meltability and shape signals are conserved irrespective of the presence or absence of distinct core promoter motifs in the majority of species. Altogether, here we delineated the conserved DNA structural signals associated with several promoter classes that may contribute to the chromatin configuration, orchestration of transcription machinery, and DNA duplex melting during the transcription process.
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Affiliation(s)
- Akkinepally Vanaja
- Department
of Biotechnology, Koneru Lakshmaiah Education
Foundation, Vaddeswaram, Guntur 522502, Andhra
Pradesh, India
- KL
College of Pharmacy, Koneru Lakshmaiah Education
Foundation, Vaddeswaram, Guntur 522502, Andhra
Pradesh, India
| | - Venkata Rajesh Yella
- Department
of Biotechnology, Koneru Lakshmaiah Education
Foundation, Vaddeswaram, Guntur 522502, Andhra
Pradesh, India
- . Tel: +91-863-2399999, Extn-1021. Website: https://www.kluniversity.in/bt/faculty-list.aspx
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