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Nemsick S, Hansen AS. Molecular models of bidirectional promoter regulation. Curr Opin Struct Biol 2024; 87:102865. [PMID: 38905929 DOI: 10.1016/j.sbi.2024.102865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/30/2024] [Accepted: 05/27/2024] [Indexed: 06/23/2024]
Abstract
Approximately 11% of human genes are transcribed by a bidirectional promoter (BDP), defined as two genes with <1 kb between their transcription start sites. Despite their evolutionary conservation and enrichment for housekeeping genes and oncogenes, the regulatory role of BDPs remains unclear. BDPs have been suggested to facilitate gene coregulation and/or decrease expression noise. This review discusses these potential regulatory functions through the context of six prospective underlying mechanistic models: a single nucleosome free region, shared transcription factor/regulator binding, cooperative negative supercoiling, bimodal histone marks, joint activation by enhancer(s), and RNA-mediated recruitment of regulators. These molecular mechanisms may act independently and/or cooperatively to facilitate the coregulation and/or decreased expression noise predicted of BDPs.
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Affiliation(s)
- Sarah Nemsick
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA.
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2
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Khaniya A, Rad SMAH, Halpin J, Tawinwung S, McLellan A, Suppipat K, Hirankarn N. Development of a compact bidirectional promoter-driven dual chimeric antigen receptor (CAR) construct targeting CD19 and CD20 in the Sleeping Beauty (SB) transposon system. J Immunother Cancer 2024; 12:e008555. [PMID: 38677881 PMCID: PMC11057265 DOI: 10.1136/jitc-2023-008555] [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] [Accepted: 04/11/2024] [Indexed: 04/29/2024] Open
Abstract
BACKGROUND A bidirectional promoter-driven chimeric antigen receptor (CAR) cassette provides the simultaneous expression of two CARs, which significantly enhances dual antigen-targeted CAR T-cell therapy. METHODS We developed a second-generation CAR directing CD19 and CD20 antigens, incorporating them in a head-to-head orientation from a bidirectional promoter using a single Sleeping Beauty transposon system. The efficacy of bidirectional promoter-driven dual CD19 and CD20 CAR T cells was determined in vitro against cell lines expressing either, or both, CD19 and CD20 antigens. In vivo antitumor activity was tested in Raji lymphoma-bearing immunodeficient NOD-scid IL2Rgammanull (NSG) mice. RESULTS Of all tested promoters, the bidirectional EF-1α promoter optimally expressed transcripts from both sense (CD19-CAR) and antisense (GFP.CD20-CAR) directions. Superior cytotoxicity, cytokine production and antigen-specific activation were observed in vitro in the bidirectional EF-1α promoter-driven CD19/CD20 CAR T cells. In contrast, a unidirectional construct driven by the EF-1α promoter, but using self-cleaving peptide-linked CD19 and CD20 CARs, showed inferior expression and in vitro function. Treatment of mice bearing advanced Raji lymphomas with bidirectional EF-1α promoter-driven CD19/CD20 CAR T cells effectively controlled tumor growth and extended the survival of mice compared with group treated with single antigen targeted CAR T cells. CONCLUSION The use of bidirectional promoters in a single vector offers advantages of size and robust CAR expression with the potential to expand use in other forms of gene therapies like CAR T cells.
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MESH Headings
- Antigens, CD19/immunology
- Antigens, CD19/genetics
- Humans
- Animals
- Antigens, CD20/genetics
- Antigens, CD20/metabolism
- Antigens, CD20/immunology
- Mice
- Receptors, Chimeric Antigen/genetics
- Receptors, Chimeric Antigen/metabolism
- Receptors, Chimeric Antigen/immunology
- DNA Transposable Elements
- Promoter Regions, Genetic
- Immunotherapy, Adoptive/methods
- Mice, Inbred NOD
- Cell Line, Tumor
- Mice, SCID
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Asmita Khaniya
- Medical Microbiology, Chulalongkorn University, Bangkok, Thailand
- Cellular Immunotherapy Research Unit, Chulalongkorn University, Bangkok, Thailand
| | | | - Josh Halpin
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Supannikar Tawinwung
- Cellular Immunotherapy Research Unit, Chulalongkorn University, Bangkok, Thailand
- Pharmacology and Physiology, Chulalongkorn University Faculty of Pharmaceutical Sciences, Bangkok, Thailand
| | - Alexander McLellan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Koramit Suppipat
- Cellular Immunotherapy Research Unit, Chulalongkorn University, Bangkok, Thailand
- Department of Research Affairs, Chulalongkorn University, Bangkok, Thailand
| | - Nattiya Hirankarn
- Center of Excellence in Immunology and Immune-mediated Diseases, Chulalongkorn University, Bangkok, Thailand
- Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
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3
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Muley VY. Editorial: Gene expression: epigenetic and transcriptional regulation in neurodegenerative diseases and ageing. Front Neurosci 2023; 17:1342890. [PMID: 38161795 PMCID: PMC10756902 DOI: 10.3389/fnins.2023.1342890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024] Open
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4
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Contreras‐Marciales ADP, López‐Guzmán SF, Benítez‐Hess ML, Oviedo N, Hernández‐Sánchez J. Characterization of the promoter region of the murine Catsper2 gene. FEBS Open Bio 2022; 12:2236-2249. [PMID: 36345591 PMCID: PMC9714369 DOI: 10.1002/2211-5463.13518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/07/2022] [Accepted: 11/07/2022] [Indexed: 11/09/2022] Open
Abstract
CATSPER2 (Cation channel sperm-associated protein 2) protein, which is part of the calcium CATSPER channel located in the membrane of the flagellar principal piece of the sperm cell, is only expressed in the testis during spermatogenesis. Deletions or mutations in the Catsper2 gene are associated with the deafness-infertility syndrome (DIS) and non-syndromic male infertility. However, the mechanisms by which Catsper2 is regulated are unknown. Here, we report the characterization of the promoter region of murine Catsper2 and the role of CTCF and CREMτ in its transcription. We report that the promoter region has transcriptional activity in both directions, as determined by observing luciferase activity in mouse Sertoli and GC-1 spg transfected cells. WGBS data analysis indicated that a CpG island identified in silico is non-methylated; Chromatin immunoprecipitation (ChIP)-seq data analysis revealed that histone marks H3K4me3 and H3K36me3 are present in the promoter and body of the Catsper2 gene respectively, indicating that Catsper2 is subject to epigenetic regulation. In addition, the murine Catsper2 core promoter was delimited to a region between -54/+189 relative to the transcription start site (TSS), where three CTCF and one CRE binding site were predicted. The functionality of these sites was determined by mutation of the CTCF sites and deletion of the CRE site. Finally, ChIP assays confirmed that CREMτ and CTCF bind to the Catsper2 minimal promoter region. This study represents the first functional analysis of the murine Catsper2 promoter region and the mechanisms that regulate its expression.
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Affiliation(s)
- Andrea del Pilar Contreras‐Marciales
- Departamento de Genética y Biología MolecularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV)Ciudad de MéxicoMexico
| | - Sergio Federico López‐Guzmán
- Departamento de Genética y Biología MolecularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV)Ciudad de MéxicoMexico
| | - María Luisa Benítez‐Hess
- Departamento de Genética y Biología MolecularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV)Ciudad de MéxicoMexico
| | - Norma Oviedo
- Unidad de Investigación Médica en Inmunología e Infectología, Centro Médico Nacional, La RazaInstituto Mexicano del Seguro SocialCiudad de MéxicoMexico
| | - Javier Hernández‐Sánchez
- Departamento de Genética y Biología MolecularCentro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV)Ciudad de MéxicoMexico
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5
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Faux T, Rytkönen KT, Mahmoudian M, Paulin N, Junttila S, Laiho A, Elo LL. Differential ATAC-seq and ChIP-seq peak detection using ROTS. NAR Genom Bioinform 2021; 3:lqab059. [PMID: 34235431 PMCID: PMC8253552 DOI: 10.1093/nargab/lqab059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 05/12/2021] [Accepted: 06/11/2021] [Indexed: 12/30/2022] Open
Abstract
Changes in cellular chromatin states fine-tune transcriptional output and ultimately lead to phenotypic changes. Here we propose a novel application of our reproducibility-optimized test statistics (ROTS) to detect differential chromatin states (ATAC-seq) or differential chromatin modification states (ChIP-seq) between conditions. We compare the performance of ROTS to existing and widely used methods for ATAC-seq and ChIP-seq data using both synthetic and real datasets. Our results show that ROTS outperformed other commonly used methods when analyzing ATAC-seq data. ROTS also displayed the most accurate detection of small differences when modeling with synthetic data. We observed that two-step methods that require the use of a separate peak caller often more accurately called enrichment borders, whereas one-step methods without a separate peak calling step were more versatile in calling sub-peaks. The top ranked differential regions detected by the methods had marked correlation with transcriptional differences of the closest genes. Overall, our study provides evidence that ROTS is a useful addition to the available differential peak detection methods to study chromatin and performs especially well when applied to study differential chromatin states in ATAC-seq data.
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Affiliation(s)
- Thomas Faux
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
| | - Kalle T Rytkönen
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
- Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, 20014, Finland
| | - Mehrad Mahmoudian
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
- Department of Future Technologies, University of Turku, FI-20014 Turku, Finland
| | - Niklas Paulin
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
| | - Sini Junttila
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
| | - Asta Laiho
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
| | - Laura L Elo
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Tykistökatu 6, 20520, Turku, Finland
- Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, 20014, Finland
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6
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Ahmad SS, Samia NSN, Khan AS, Turjya RR, Khan MAAK. Bidirectional promoters: an enigmatic genome architecture and their roles in cancers. Mol Biol Rep 2021; 48:6637-6644. [PMID: 34378109 DOI: 10.1007/s11033-021-06612-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 07/29/2021] [Indexed: 11/28/2022]
Abstract
Bidirectional promoters are the transcription regulatory regions of genes positioned head-to-head on opposite strands. Specific sequence signals, chromatin modifications and three-dimensional structures of the transcription site facilitate the unconventional yet tightly regulated transcription proceeding in both directions from these promoters. Mutations or aberrant epigenetic changes can lead to abnormal enhanced or reduced expression from either of the bidirectionally transcribed genes resulting in tumorigenesis. Moreover, bidirectionally transcribed genes might also contribute towards the immune regulation in tumor microenvironment. In this review, we aimed to expound the characteristic features of bidirectional promoters alongside their transcriptional regulations, and ultimately, the association of these enigmatic genomic elements in different cancers.
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Affiliation(s)
- Sheikh Shafin Ahmad
- Department of Mathematics and Natural Sciences, Brac University, Dhaka, Bangladesh
| | | | - Auroni Semonti Khan
- Department of Genetic Engineering and Biotechnology, Jagannath University, Dhaka, Bangladesh
| | - Rafeed Rahman Turjya
- Department of Mathematics and Natural Sciences, Brac University, Dhaka, Bangladesh
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7
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Brázda V, Bartas M, Bowater RP. Evolution of Diverse Strategies for Promoter Regulation. Trends Genet 2021; 37:730-744. [PMID: 33931265 DOI: 10.1016/j.tig.2021.04.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/31/2021] [Accepted: 04/01/2021] [Indexed: 12/15/2022]
Abstract
DNA is fundamentally important for all cellular organisms due to its role as a store of hereditary genetic information. The precise and accurate regulation of gene transcription depends primarily on promoters, which vary significantly within and between genomes. Some promoters are rich in specific types of bases, while others have more varied, complex sequence characteristics. However, it is not only base sequence but also epigenetic modifications and altered DNA structure that regulate promoter activity. Significantly, many promoters across all organisms contain sequences that can form intrastrand hairpins (cruciforms) or four-stranded structures (G-quadruplex or i-motif). In this review we integrate recent studies on promoter regulation that highlight the importance of DNA structure in the evolutionary adaptation of promoter sequences.
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Affiliation(s)
- Václav Brázda
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Martin Bartas
- Department of Biology and Ecology/Institute of Environmental Technologies, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Richard P Bowater
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
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8
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Al-Obaide MAI, Al-Obaidi II, Vasylyeva TL. Unexplored regulatory sequences of divergently paired GLA and HNRNPH2 loci pertinent to Fabry disease in human kidney and skin cells: Presence of an active bidirectional promoter. Exp Ther Med 2020; 21:154. [PMID: 33456521 PMCID: PMC7792484 DOI: 10.3892/etm.2020.9586] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/01/2020] [Indexed: 12/21/2022] Open
Abstract
Fabry disease (FD) is a rare hereditary disorder characterized by a wide range of symptoms caused by a variety of mutations in the galactosidase α (GLA) gene. The heterogeneous nuclear ribonucleoprotein (HNRNPH2) gene is divergently paired with GLA on chromosome X and is thought to be implicated in FD. However, insufficient information is available on the regulatory mechanisms associated with the expression of HNRNPH2 and the GLA loci. Therefore, the current study performed bioinformatics analyses to assess the GLA and HNRNPH2 loci and investigate the regulatory mechanisms involved in the expression of each gene. The regulatory mechanisms underlying GLA and HNRNPH2 were revealed. The expression of each gene was associated with a bidirectional promoter (BDP) characterized by the absence of TATA box motifs and the presence of specific transcription factor binding sites (TFBSs) and a CpG Island (CGI). The nuclear run-on transcription assay confirmed the activity of BDP GLA and HNRNPH2 transcription in 293T. Methylation-specific PCR analysis demonstrated a statistically significant variation in the DNA methylation pattern of BDP in several cell lines, including human adult epidermal keratinocytes (AEKs), human renal glomerular endothelial cells, human renal epithelial cells and 293T cells. The highest observed significance was demonstrated in AEKs (P<0.05). The results of the chromatin-immunoprecipitation assay using 293T cells identified specific TFBS motifs for Yin Yang 1 and nuclear respiratory factor 1 transcription factors in BDPs. The National Center for Biotechnology Information-single nucleotide polymorphism database revealed pathogenic variants in the BDP sequence. Additionally, a previously reported variant associated with a severe heterozygous female case of GLA FD was mapped in BDP. The results of the present study suggested that the expression of the divergent paired loci, GLA and HNRNPH2, were controlled by BDP. Mutations in BDP may also serve a role in FD and may explain clinical disease diversity.
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Affiliation(s)
- Mohammed A Ibrahim Al-Obaide
- Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
| | - Ibtisam I Al-Obaidi
- Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
| | - Tetyana L Vasylyeva
- Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
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9
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He K, Rad SMAH, Poudel A, McLellan AD. Compact Bidirectional Promoters for Dual-Gene Expression in a Sleeping Beauty Transposon. Int J Mol Sci 2020; 21:ijms21239256. [PMID: 33291599 PMCID: PMC7731152 DOI: 10.3390/ijms21239256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/26/2020] [Accepted: 12/02/2020] [Indexed: 12/13/2022] Open
Abstract
Promoter choice is an essential consideration for transgene expression in gene therapy. The expression of multiple genes requires ribosomal entry or skip sites, or the use of multiple promoters. Promoter systems comprised of two separate, divergent promoters may significantly increase the size of genetic cassettes intended for use in gene therapy. However, an alternative approach is to use a single, compact, bidirectional promoter. We identified strong and stable bidirectional activity of the RPBSA synthetic promoter comprised of a fragment of the human Rpl13a promoter, together with additional intron/exon structures. The Rpl13a-based promoter drove long-term bidirectional activity of fluorescent proteins. Similar results were obtained for the EF1-α and LMP2/TAP1 promoters. However, in a lentiviral vector, the divergent bidirectional systems failed to produce sufficient titres to translate into an expression system for dual chimeric antigen receptor (CAR) expression. Although bidirectional promoters show excellent applicability to drive short RNA in Sleeping Beauty transposon systems, their possible use in the lentiviral applications requiring longer and more complex RNA, such as dual-CAR cassettes, is limited.
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10
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Zhou H, Simion V, Pierce JB, Haemmig S, Chen AF, Feinberg MW. LncRNA-MAP3K4 regulates vascular inflammation through the p38 MAPK signaling pathway and cis-modulation of MAP3K4. FASEB J 2020; 35:e21133. [PMID: 33184917 DOI: 10.1096/fj.202001654rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 09/23/2020] [Accepted: 10/08/2020] [Indexed: 12/12/2022]
Abstract
Chronic vascular inflammation plays a key role in the pathogenesis of atherosclerosis. Long non-coding RNAs (lncRNAs) have emerged as essential inflammation regulators. We identify a novel lncRNA termed lncRNA-MAP3K4 that is enriched in the vessel wall and regulates vascular inflammation. In the aortic intima, lncRNA-MAP3K4 expression was reduced by 50% during the progression of atherosclerosis (chronic inflammation) and 70% during endotoxemia (acute inflammation). lncRNA-MAP3K4 knockdown reduced the expression of key inflammatory factors (eg, ICAM-1, E-selectin, MCP-1) in endothelial cells or vascular smooth muscle cells and decreased monocytes adhesion to endothelium, as well as reducing TNF-α, IL-1β, COX2 expression in macrophages. Mechanistically, lncRNA-MAP3K4 regulates inflammation through the p38 MAPK signaling pathway. lncRNA-MAP3K4 shares a bidirectional promoter with MAP3K4, an upstream regulator of the MAPK signaling pathway, and regulates its transcription in cis. lncRNA-MAP3K4 and MAP3K4 show coordinated expression in response to inflammation in vivo and in vitro. Similar to lncRNA-MAP3K4, MAP3K4 knockdown reduced the expression of inflammatory factors in several different vascular cells. Furthermore, lncRNA-MAP3K4 and MAP3K4 knockdown showed cooperativity in reducing inflammation in endothelial cells. Collectively, these findings unveil the role of a novel lncRNA in vascular inflammation by cis-regulating MAP3K4 via a p38 MAPK pathway.
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Affiliation(s)
- Haoyang Zhou
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Viorel Simion
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Jacob B Pierce
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stefan Haemmig
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alex F Chen
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Mark W Feinberg
- Department of Medicine, Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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11
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Sauty SM, Shaban K, Yankulov K. Gene repression in S. cerevisiae-looking beyond Sir-dependent gene silencing. Curr Genet 2020; 67:3-17. [PMID: 33037902 DOI: 10.1007/s00294-020-01114-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 01/09/2023]
Abstract
Gene silencing by the SIR (Silent Information Region) family of proteins in S. cerevisiae has been extensively studied and has served as a founding paradigm for our general understanding of gene repression and its links to histone deacetylation and chromatin structure. In recent years, our understanding of other mechanisms of gene repression in S.cerevisiae was significantly advanced. In this review, we focus on such Sir-independent mechanisms of gene repression executed by various Histone Deacetylases (HDACs) and Histone Methyl Transferases (HMTs). We focus on the genes regulated by these enzymes and their known mechanisms of action. We describe the cooperation and redundancy between HDACs and HMTs, and their involvement in gene repression by non-coding RNAs or by their non-histone substrates. We also propose models of epigenetic transmission of the chromatin structures produced by these enzymes and discuss these in the context of gene repression phenomena in other organisms. These include the recycling of the epigenetic marks imposed by HMTs or the recycling of the complexes harboring HDACs.
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Affiliation(s)
- Safia Mahabub Sauty
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Kholoud Shaban
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada
| | - Krassimir Yankulov
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada.
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12
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Tu J, Li X, Wang J. Characterization of bidirectional gene pairs in The Cancer Genome Atlas (TCGA) dataset. PeerJ 2019; 7:e7107. [PMID: 31245179 PMCID: PMC6585903 DOI: 10.7717/peerj.7107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/09/2019] [Indexed: 12/15/2022] Open
Abstract
The “bidirectional gene pair” indicates a particular head-to-head gene organization in which transcription start sites of two genes are located on opposite strands of genomic DNA within a region of one kb. Despite bidirectional gene pairs are well characterized, little is known about their expression profiles and regulation features in tumorigenesis. We used RNA-seq data from The Cancer Genome Atlas (TCGA) dataset for a systematic analysis of the expression profiles of bidirectional gene pairs in 13 cancer datasets. Gene pairs on the opposite strand with transcription end site distance within one kb or on the same strand with the distance of two genes between 1–10 kb and gene pairs comprising two randomly chosen genes were used as control gene pairs (CG1, CG2, and random). We identified and characterized up-/down-regulated genes by comparing the expression level between tumors and adjacent normal tissues in 13 TCGA datasets. There were no consistently significant difference in the percentage of up-/down-regulated genes between bidirectional and control/random genes in most of TCGA datasets. However, the percentage of bidirectional gene pairs comprising two up- or two down-regulated genes was significantly higher than gene pairs from CG1/2 in 12/11 analyzed TCGA datasets and the random gene pairs in all 13 TCGA datasets. Then we identified the methylation correlated bidirectional genes to explore the regulatory mechanism of bidirectional genes. Like the differentially expressed gene pairs, the bidirectional genes in a pair were significantly prone to be both hypo- or hyper-methylation correlated genes in 12/13 TCGA datasets when comparing to the CG2/random gene pairs despite no significant difference between the percentages of hypo-/hyper-methylation correlated genes in bidirectional and CG2/random genes in most of TCGA datasets. Finally, we explored the correlation between bidirectional genes and patient’s survival, identifying prognostic bidirectional genes and prognostic bidirectional gene pairs in each TCGA dataset. Remarkably, we found a group of prognostic bidirectional gene pairs in which the combination of two protein coding genes with different expression level correlated with different survival prognosis in survival analysis for OS. The percentage of these gene pairs in bidirectional gene pair were significantly higher than the gene pairs in controls in COAD datasets and lower in none of 13 TCGA datasets.
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Affiliation(s)
- Juchuanli Tu
- College of Life Sciences, Beijing Normal University, Beijing, China.,National Institute of Biological Sciences, Beijing, China
| | - Xiaolu Li
- National Institute of Biological Sciences, Beijing, China
| | - Jianjun Wang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
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