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Dashti P, Lewallen EA, Gordon JAR, Montecino MA, Davie JR, Stein GS, van Leeuwen JPTM, van der Eerden BCJ, van Wijnen AJ. Epigenetic regulators controlling osteogenic lineage commitment and bone formation. Bone 2024; 181:117043. [PMID: 38341164 DOI: 10.1016/j.bone.2024.117043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/08/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Bone formation and homeostasis are controlled by environmental factors and endocrine regulatory cues that initiate intracellular signaling pathways capable of modulating gene expression in the nucleus. Bone-related gene expression is controlled by nucleosome-based chromatin architecture that limits the accessibility of lineage-specific gene regulatory DNA sequences and sequence-specific transcription factors. From a developmental perspective, bone-specific gene expression must be suppressed during the early stages of embryogenesis to prevent the premature mineralization of skeletal elements during fetal growth in utero. Hence, bone formation is initially inhibited by gene suppressive epigenetic regulators, while other epigenetic regulators actively support osteoblast differentiation. Prominent epigenetic regulators that stimulate or attenuate osteogenesis include lysine methyl transferases (e.g., EZH2, SMYD2, SUV420H2), lysine deacetylases (e.g., HDAC1, HDAC3, HDAC4, HDAC7, SIRT1, SIRT3), arginine methyl transferases (e.g., PRMT1, PRMT4/CARM1, PRMT5), dioxygenases (e.g., TET2), bromodomain proteins (e.g., BRD2, BRD4) and chromodomain proteins (e.g., CBX1, CBX2, CBX5). This narrative review provides a broad overview of the covalent modifications of DNA and histone proteins that involve hundreds of enzymes that add, read, or delete these epigenetic modifications that are relevant for self-renewal and differentiation of mesenchymal stem cells, skeletal stem cells and osteoblasts during osteogenesis.
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Affiliation(s)
- Parisa Dashti
- Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands; Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Eric A Lewallen
- Department of Biological Sciences, Hampton University, Hampton, VA, USA
| | | | - Martin A Montecino
- Institute of Biomedical Sciences, Faculty of Medicine, Universidad Andres Bello, Santiago, Chile; Millennium Institute Center for Genome Regulation (CRG), Santiago, Chile
| | - James R Davie
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, Manitoba R3E 0J9, Canada; CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, Manitoba R3E 0V9, Canada.
| | - Gary S Stein
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | | | - Bram C J van der Eerden
- Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands.
| | - Andre J van Wijnen
- Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands; Department of Biochemistry, University of Vermont, Burlington, VT, USA.
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Theil AF, Häckes D, Lans H. TFIIH central activity in nucleotide excision repair to prevent disease. DNA Repair (Amst) 2023; 132:103568. [PMID: 37977600 DOI: 10.1016/j.dnarep.2023.103568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/22/2023] [Accepted: 09/03/2023] [Indexed: 11/19/2023]
Abstract
The heterodecameric transcription factor IIH (TFIIH) functions in multiple cellular processes, foremost in nucleotide excision repair (NER) and transcription initiation by RNA polymerase II. TFIIH is essential for life and hereditary mutations in TFIIH cause the devastating human syndromes xeroderma pigmentosum, Cockayne syndrome or trichothiodystrophy, or combinations of these. In NER, TFIIH binds to DNA after DNA damage is detected and, using its translocase and helicase subunits XPB and XPD, opens up the DNA and checks for the presence of DNA damage. This central activity leads to dual incision and removal of the DNA strand containing the damage, after which the resulting DNA gap is restored. In this review, we discuss new structural and mechanistic insights into the central function of TFIIH in NER. Moreover, we provide an elaborate overview of all currently known patients and diseases associated with inherited TFIIH mutations and describe how our understanding of TFIIH function in NER and transcription can explain the different disease features caused by TFIIH deficiency.
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Affiliation(s)
- Arjan F Theil
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, the Netherlands
| | - David Häckes
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, the Netherlands
| | - Hannes Lans
- Department of Molecular Genetics, Erasmus MC Cancer Institute, Erasmus University Medical Center, 3015 GD Rotterdam, the Netherlands.
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Chen X, Liu Z, Lou C, Guan Y, Ouyang Q, Xiang Y. Improving cooperativity of transcription activators by oligomerization domains in mammalian cells. Synth Syst Biotechnol 2023; 8:114-120. [PMID: 36605704 PMCID: PMC9804245 DOI: 10.1016/j.synbio.2022.12.003] [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: 10/04/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Cooperative activation is critical for the applications of synthetic biology in mammalian cells. In this study, we have developed cooperative transcription factor by fusing oligomerization domain in mammalian cells. Firstly, we demonstrated that two oligomerized domains (CI434 and CI) successfully improved transcription factor cooperativity in bacterial cells but failed to increase cooperativity in mammalian cells, possibly because the additional mammalian activation domain disrupted their oligomerization capability. Therefore, we chose a different type of oligomerized domain (CarHC), whose ability to oligomerize is not dependent on its C-terminal domains, to fuse with a transcription factor (RpaR) and activation domain (VTR3), forming a potential cooperative transcription activator RpaR-CarH-VTR3 for mammalian regulatory systems. Compared with RpaR-VTR3, the cooperativity of RpaR-CarH-VTR3 was significantly improved with higher Hill coefficient and a narrower input range in the inducible switch system in mammalian cells. Moreover, a mathematical model based on statistical mechanics model was developed and the simulation results supported the hypothesis that the tetramer of the CarH domain in mammalian cells was the reason for the cooperative capacity of RpaR-CarH-VTR3.
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Affiliation(s)
- Xinmao Chen
- School of Physics, Peking University, Beijing, 100871, China
| | - Ziming Liu
- Center for Cell and Gene Circuit Design, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Chunbo Lou
- Center for Cell and Gene Circuit Design, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Ying Guan
- School of Physics, Peking University, Beijing, 100871, China
- Department of Chemical Engineering, Tsinghua University, Beijing, 100871, China
- Center for Cell and Gene Circuit Design, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Qi Ouyang
- School of Physics, Peking University, Beijing, 100871, China
| | - Yanhui Xiang
- Center for Cell and Gene Circuit Design, CAS Key Laboratory of Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
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Richter WF, Nayak S, Iwasa J, Taatjes DJ. The Mediator complex as a master regulator of transcription by RNA polymerase II. Nat Rev Mol Cell Biol 2022; 23:732-749. [PMID: 35725906 PMCID: PMC9207880 DOI: 10.1038/s41580-022-00498-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2022] [Indexed: 02/08/2023]
Abstract
The Mediator complex, which in humans is 1.4 MDa in size and includes 26 subunits, controls many aspects of RNA polymerase II (Pol II) function. Apart from its size, a defining feature of Mediator is its intrinsic disorder and conformational flexibility, which contributes to its ability to undergo phase separation and to interact with a myriad of regulatory factors. In this Review, we discuss Mediator structure and function, with emphasis on recent cryogenic electron microscopy data of the 4.0-MDa transcription preinitiation complex. We further discuss how Mediator and sequence-specific DNA-binding transcription factors enable enhancer-dependent regulation of Pol II function at distal gene promoters, through the formation of molecular condensates (or transcription hubs) and chromatin loops. Mediator regulation of Pol II reinitiation is also discussed, in the context of transcription bursting. We propose a working model for Mediator function that combines experimental results and theoretical considerations related to enhancer-promoter interactions, which reconciles contradictory data regarding whether enhancer-promoter communication is direct or indirect. We conclude with a discussion of Mediator's potential as a therapeutic target and of future research directions.
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Affiliation(s)
- William F Richter
- Department of Biochemistry, University of Colorado, Boulder, CO, USA
| | - Shraddha Nayak
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Dylan J Taatjes
- Department of Biochemistry, University of Colorado, Boulder, CO, USA.
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Rawson JMO, Nikolaitchik OA, Shakya S, Keele BF, Pathak VK, Hu WS. Transcription Start Site Heterogeneity and Preferential Packaging of Specific Full-Length RNA Species Are Conserved Features of Primate Lentiviruses. Microbiol Spectr 2022; 10:e0105322. [PMID: 35736240 PMCID: PMC9430795 DOI: 10.1128/spectrum.01053-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/05/2022] [Indexed: 11/22/2022] Open
Abstract
HIV-1 must package its RNA genome to generate infectious viruses. Recent studies have revealed that during genome packaging, HIV-1 not only excludes cellular mRNAs, but also distinguishes among full-length viral RNAs. Using NL4-3 and MAL molecular clones, multiple transcription start sites (TSS) were identified, which generate full-length RNAs that differ by only a few nucleotides at the 5' end. However, HIV-1 selectively packages RNAs containing one guanosine (1G RNA) over RNAs with three guanosines (3G RNA) at the 5' end. Thus, the 5' context of HIV-1 full-length RNA can affect its function. To determine whether the regulation of genome packaging by TSS usage is unique to NL4-3 and MAL, we examined 15 primate lentiviruses including transmitted founder viruses of HIV-1, HIV-2, and several simian immunodeficiency viruses (SIVs). We found that all 15 viruses used multiple TSS to some extent. However, the level of TSS heterogeneity in infected cells varied greatly, even among closely related viruses belonging to the same subtype. Most viruses also exhibited selective packaging of specific full-length viral RNA species into particles. These findings demonstrate that TSS heterogeneity and selective packaging of certain full-length viral RNA species are conserved features of primate lentiviruses. In addition, an SIV strain closely related to the progenitor virus that gave rise to HIV-1 group M, the pandemic pathogen, exhibited TSS usage similar to some HIV-1 strains and preferentially packaged 1G RNA. These findings indicate that multiple TSS usage and selective packaging of a particular unspliced RNA species predate the emergence of HIV-1. IMPORTANCE Unspliced HIV-1 RNA serves two important roles during viral replication: as the virion genome and as the template for translation of Gag/Gag-Pol. Previous studies of two HIV-1 molecular clones have concluded that the TSS usage affects unspliced HIV-1 RNA structures and functions. To investigate the evolutionary origin of this replication strategy, we determined TSS of HIV-1 RNA in infected cells and virions for 15 primate lentiviruses. All HIV-1 isolates examined, including several transmitted founder viruses, utilized multiple TSS and selected a particular RNA species for packaging. Furthermore, these features were observed in SIVs related to the progenitors of HIV-1, suggesting that these characteristics originated from the ancestral viruses. HIV-2, SIVs related to HIV-2, and other SIVs also exhibited multiple TSS and preferential packaging of specific unspliced RNA species, demonstrating that this replication strategy is broadly conserved across primate lentiviruses.
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Affiliation(s)
- Jonathan M. O. Rawson
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Olga A. Nikolaitchik
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Saurabh Shakya
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Brandon F. Keele
- AIDS and Cancer Virus Program, Frederick National Laboratory, Frederick, Maryland, USA
| | - Vinay K. Pathak
- Viral Mutation Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
| | - Wei-Shau Hu
- Viral Recombination Section, HIV Dynamics and Replication Program, National Cancer Institute at Frederick, Frederick, Maryland, USA
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Differences in RNA polymerase II complexes and their interactions with surrounding chromatin on human and cytomegalovirus genomes. Nat Commun 2022; 13:2006. [PMID: 35422111 PMCID: PMC9010409 DOI: 10.1038/s41467-022-29739-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 03/21/2022] [Indexed: 12/29/2022] Open
Abstract
Interactions of the RNA polymerase II (Pol II) preinitiation complex (PIC) and paused early elongation complexes with the first downstream (+1) nucleosome are thought to be functionally important. However, current methods are limited for investigating these relationships, both for cellular chromatin and the human cytomegalovirus (HCMV) genome. Digestion with human DNA fragmentation factor (DFF) before immunoprecipitation (DFF-ChIP) precisely revealed both similarities and major differences in PICs driven by TBP on the host genome in comparison with PICs driven by TBP or the viral-specific, late initiation factor UL87 on the viral genome. Host PICs and paused Pol II complexes are frequently found in contact with the +1 nucleosome and paused Pol II can also be found in a complex involved in the initial invasion of the +1 nucleosome. In contrast, viral transcription complexes have very limited nucleosomal interactions, reflecting a relative lack of chromatinization of transcriptionally active regions of HCMV genomes. Here the authors digested chromatin with DNA fragmentation factor (DFF) prior to chromatin immunoprecipitation (DFF-ChIP) to depict transcription complex interactions with neighboring nucleosomes in cells. Applying this method to human cytomegalovirus (HMCV)-infected cells, they find that the viral genome is underchromatinized, leading to fewer transcription complex interactions with nucleosomes.
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