1
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Wettasinghe AP, Seifi MO, Bravo M, Adams AC, Patel A, Lou M, Kahanda D, Peng H, Stelling AL, Fan L, Slinker JD. Molecular wrench activity of DNA helicases: Keys to modulation of rapid kinetics in DNA repair. Protein Sci 2023; 32:e4815. [PMID: 37874269 PMCID: PMC10659936 DOI: 10.1002/pro.4815] [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: 07/22/2023] [Revised: 10/03/2023] [Accepted: 10/19/2023] [Indexed: 10/25/2023]
Abstract
DNA helicase activity is essential for the vital DNA metabolic processes of recombination, replication, transcription, translation, and repair. Recently, an unexpected, rapid exponential ATP-stimulated DNA unwinding rate was observed from an Archaeoglobus fulgidus helicase (AfXPB) as compared to the slower conventional helicases from Sulfolobus tokodaii, StXPB1 and StXPB2. This unusual rapid activity suggests a "molecular wrench" mechanism arising from the torque applied by AfXPB on the duplex structure in transitioning from open to closed conformations. However, much remains to be understood. Here, we investigate the concentration dependence of DNA helicase binding and ATP-stimulated kinetics of StXPB2 and AfXPB, as well as their binding and activity in Bax1 complexes, via an electrochemical assay with redox-active DNA monolayers. StXPB2 ATP-stimulated activity is concentration-independent from 8 to 200 nM. Unexpectedly, AfXPB activity is concentration-dependent in this range, with exponential rate constants varying from seconds at concentrations greater than 20 nM to thousands of seconds at lower concentrations. At 20 nM, rapid exponential signal decay ensues, linearly reverses, and resumes with a slower exponential decay. This change in AfXPB activity as a function of its concentration is rationalized as the crossover between the fast molecular wrench and slower conventional helicase modes. AfXPB-Bax1 inhibits rapid activity, whereas the StXPB2-Bax1 complex induces rapid kinetics at higher concentrations. This activity is rationalized with the crystal structures of these complexes. These findings illuminate the different physical models governing molecular wrench activity for improved biological insight into a key factor in DNA repair.
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Affiliation(s)
| | - Melodee O. Seifi
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
| | - Marco Bravo
- Department of BiochemistryUniversity of CaliforniaRiversideCaliforniaUSA
| | - Austen C. Adams
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
| | - Aman Patel
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
| | - Monica Lou
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
| | - Dimithree Kahanda
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
| | - Hao‐Che Peng
- Department of ChemistryThe University of Texas at DallasRichardsonTexasUSA
| | | | - Li Fan
- Department of ChemistryThe University of Texas at DallasRichardsonTexasUSA
| | - Jason D. Slinker
- Department of PhysicsThe University of Texas at DallasRichardsonTexasUSA
- Department of ChemistryThe University of Texas at DallasRichardsonTexasUSA
- Department of Materials Science and EngineeringThe University of Texas at DallasRichardsonTexasUSA
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2
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Zhao JH, Huang YY, Wang H, Yang XM, Li Y, Pu M, Zhou SX, Zhang JW, Zhao ZX, Li GB, Hassan B, Hu XH, Chen X, Xiao S, Wu XJ, Fan J, Wang WM. Golovinomyces cichoracearum effector-associated nuclear localization of RPW8.2 amplifies its expression to boost immunity in Arabidopsis. THE NEW PHYTOLOGIST 2023; 238:367-382. [PMID: 36522832 DOI: 10.1111/nph.18682] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Arabidopsis RESISTANCE TO POWDERY MILDEW 8.2 (RPW8.2) is specifically induced by the powdery mildew (PM) fungus (Golovinomyces cichoracearum) in the infected epidermal cells to activate immunity. However, the mechanism of RPW8.2-induction is not well understood. Here, we identify a G. cichoracearum effector that interacts with RPW8.2, named Gc-RPW8.2 interacting protein 1 (GcR8IP1), by a yeast two-hybrid screen of an Arabidopsis cDNA library. GcR8IP1 is physically associated with RPW8.2 with its REALLY INTERESTING NEW GENE finger domain that is essential and sufficient for the association. GcR8IP1 was secreted and translocated into the nucleus of host cell infected with PM. Association of GcR8IP1 with RPW8.2 led to an increase in RPW8.2 in the nucleus. In turn, the nucleus-localized RPW8.2 promoted the activity of the RPW8.2 promoter, resulting in transcriptional self-amplification of RPW8.2 to boost immunity at infection sites. Additionally, ectopic expression or host-induced gene silencing of GcR8IP1 supported its role as a virulence factor in PM. Altogether, our results reveal a mechanism of RPW8.2-dependent defense strengthening via altered partitioning of RPW8.2 and transcriptional self-amplification triggered by a PM fungal effector, which exemplifies an atypical form of effector-triggered immunity.
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Affiliation(s)
- Jing-Hao Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Yan-Yan Huang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - He Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Xue-Mei Yang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Yan Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Mei Pu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Shi-Xin Zhou
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Ji-Wei Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Zhi-Xue Zhao
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Guo-Bang Li
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Beenish Hassan
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Xiao-Hong Hu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Xuewei Chen
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD, 20850, USA
| | - Xian-Jun Wu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Jing Fan
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
| | - Wen-Ming Wang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China and Rice Research Institute, Sichuan Agricultural University, Chengdu, 611131, China
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3
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Xie G, Zhu A, Gu X. Converged DNA Damage Response Renders Human Hepatocellular Carcinoma Sensitive to CDK7 Inhibition. Cancers (Basel) 2022; 14:cancers14071714. [PMID: 35406486 PMCID: PMC8996977 DOI: 10.3390/cancers14071714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer. HCC has a dismal five-year mortality estimate of >95%, ranking as the fourth leading cause of cancer-related mortality worldwide. Despite the recent progression in the treatment of HCC with multikinase inhibitors, immunotherapy, and antiangiogenic monoclonal antibodies, among other newly emerging therapeutics, the efficacy has varied among patients, making HCC a high priority for developing novel targeted therapeutic agents. CDK7 has been exploited as a therapeutic target in HCC. In the present study, we demonstrated that HCC cells were highly susceptible to THZ1, a selective covalent CDK7 inhibitor. We further discovered that transcription factor MYC-promoted cell proliferation renders cancer cells hypersensitive to apoptotic cell death with THZ1 treatment. Our findings indicate that targeting CDK7 with THZ1 may be a new plausible strategy for treating HCC, in which MYC plays crucial roles in cell proliferation and tumor growth. Abstract Hepatocellular carcinoma (HCC) is a lethal malignancy with high mortality. The inhibition of cyclin-dependent kinase 7 (CDK7) activity has shown therapeutic efficacy in HCC. However, the underlying molecular mechanisms remain elusive. Here, we show that three HCC lines, HepG2, Hep3B, and SK-Hep-1, were highly susceptible to the CDK7 inhibitor THZ1. In mouse models, THZ1 effectively reduced HepG2 tumor growth and tumor weight. THZ1 arrested cell cycle and triggered MYC-related apoptosis in HepG2. To evaluate how MYC protein levels affected THZ1-induced apoptotic cell death, we overexpressed MYC in HepG2 and found that exogenously overexpressed MYC promoted cell cycle progression and increased cells in the S phase. THZ1 drastically engendered the apoptosis of MYC-overexpressing HepG2 cells in the S and G2/M phases. Importantly, transcription-inhibition-induced apoptosis is associated with DNA damage, and exogenous MYC expression further enhanced the THZ1-induced DNA damage response in MYC-overexpressing HepG2 cells. Consistently, in the HepG2 xenografts, THZ1 treatment was associated with DNA-damage-induced cell death. Together, our data indicate that the converged effect of MYC-promoted cell cycle progression and CDK7 inhibition by THZ1 confers the hypersensitivity of HCC to DNA-damage-induced cell death. Our findings may suggest a new therapeutic strategy of THZ1 against HCC.
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Affiliation(s)
- Guiqin Xie
- Department of Oral Pathology, Howard University, 600 W. Street NW, Washington, DC 20059, USA;
- Cancer Center, Howard University, 600 W. Street NW, Washington, DC 20059, USA
- Correspondence: (G.X.); (X.G.)
| | - Ailin Zhu
- Department of Oral Pathology, Howard University, 600 W. Street NW, Washington, DC 20059, USA;
| | - Xinbin Gu
- Department of Oral Pathology, Howard University, 600 W. Street NW, Washington, DC 20059, USA;
- Cancer Center, Howard University, 600 W. Street NW, Washington, DC 20059, USA
- Correspondence: (G.X.); (X.G.)
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4
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Yang C, Fujiwara R, Kim HJ, Basnet P, Zhu Y, Colón JJG, Steimle S, Garcia BA, Kaplan CD, Murakami K. Structural visualization of de novo transcription initiation by Saccharomyces cerevisiae RNA polymerase II. Mol Cell 2022; 82:660-676.e9. [PMID: 35051353 PMCID: PMC8818039 DOI: 10.1016/j.molcel.2021.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 11/04/2021] [Accepted: 12/15/2021] [Indexed: 02/05/2023]
Abstract
Previous structural studies of the initiation-elongation transition of RNA polymerase II (pol II) transcription have relied on the use of synthetic oligonucleotides, often artificially discontinuous to capture pol II in the initiating state. Here, we report multiple structures of initiation complexes converted de novo from a 33-subunit yeast pre-initiation complex (PIC) through catalytic activities and subsequently stalled at different template positions. We determine that PICs in the initially transcribing complex (ITC) can synthesize a transcript of ∼26 nucleotides before transitioning to an elongation complex (EC) as determined by the loss of general transcription factors (GTFs). Unexpectedly, transition to an EC was greatly accelerated when an ITC encountered a downstream EC stalled at promoter proximal regions and resulted in a collided head-to-end dimeric EC complex. Our structural analysis reveals a dynamic state of TFIIH, the largest of GTFs, in PIC/ITC with distinct functional consequences at multiple steps on the pathway to elongation.
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Affiliation(s)
- Chun Yang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A
| | - Rina Fujiwara
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA,Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Pratik Basnet
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yunye Zhu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Jose J. Gorbea Colón
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Stefan Steimle
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Craig D. Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A.,Lead contact,Correspondence to:
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5
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Compe E, Egly JM. The Long Road to Understanding RNAPII Transcription Initiation and Related Syndromes. Annu Rev Biochem 2021; 90:193-219. [PMID: 34153211 DOI: 10.1146/annurev-biochem-090220-112253] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In eukaryotes, transcription of protein-coding genes requires the assembly at core promoters of a large preinitiation machinery containing RNA polymerase II (RNAPII) and general transcription factors (GTFs). Transcription is potentiated by regulatory elements called enhancers, which are recognized by specific DNA-binding transcription factors that recruit cofactors and convey, following chromatin remodeling, the activating cues to the preinitiation complex. This review summarizes nearly five decades of work on transcription initiation by describing the sequential recruitment of diverse molecular players including the GTFs, the Mediator complex, and DNA repair factors that support RNAPII to enable RNA synthesis. The elucidation of the transcription initiation mechanism has greatly benefited from the study of altered transcription components associated with human diseases that could be considered transcription syndromes.
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Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; ,
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, INSERM, Université de Strasbourg, 67404 Illkirch CEDEX, Commune Urbaine de Strasbourg, France; , .,College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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6
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van Eeuwen T, Shim Y, Kim HJ, Zhao T, Basu S, Garcia BA, Kaplan CD, Min JH, Murakami K. Cryo-EM structure of TFIIH/Rad4-Rad23-Rad33 in damaged DNA opening in nucleotide excision repair. Nat Commun 2021; 12:3338. [PMID: 34099686 PMCID: PMC8184850 DOI: 10.1038/s41467-021-23684-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 05/05/2021] [Indexed: 11/08/2022] Open
Abstract
The versatile nucleotide excision repair (NER) pathway initiates as the XPC-RAD23B-CETN2 complex first recognizes DNA lesions from the genomic DNA and recruits the general transcription factor complex, TFIIH, for subsequent lesion verification. Here, we present a cryo-EM structure of an NER initiation complex containing Rad4-Rad23-Rad33 (yeast homologue of XPC-RAD23B-CETN2) and 7-subunit coreTFIIH assembled on a carcinogen-DNA adduct lesion at 3.9-9.2 Å resolution. A ~30-bp DNA duplex could be mapped as it straddles between Rad4 and the Ssl2 (XPB) subunit of TFIIH on the 3' and 5' side of the lesion, respectively. The simultaneous binding with Rad4 and TFIIH was permitted by an unwinding of DNA at the lesion. Translocation coupled with torque generation by Ssl2 and Rad4 would extend the DNA unwinding at the lesion and deliver the damaged strand to Rad3 (XPD) in an open form suitable for subsequent lesion scanning and verification.
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Affiliation(s)
- Trevor van Eeuwen
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yoonjung Shim
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA
| | - Hee Jong Kim
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Tingting Zhao
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shrabani Basu
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jung-Hyun Min
- Department of Chemistry and Biochemistry, Baylor University, Waco, TX, USA.
| | - Kenji Murakami
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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7
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Assessment on the influence of TLR4 and DNA repair genes in laryngeal cancer susceptibility: a selective examination in a Romanian case control study. REV ROMANA MED LAB 2021. [DOI: 10.2478/rrlm-2021-0005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
Background: Tumor characterization through the study of molecular biology has become an invaluable tool in understanding cancer development and evolution due to its relationship with chromosomal mutations, alterations or aberrations. The purpose of this study was to investigate the involvement of genes such as TLR-4 and DNA repair pathways (XRCC1 and XPD) in laryngeal cancer susceptibility in a Romanian population. Method: We performed a case-control study on 157 laryngeal cancer patients and 101 healthy controls. Genetic testing was carried out using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism. Results: We identified the Gln allele of the XPDLys751Gln polymorphism as an individual risk factor in laryngeal cancer development (Gln vs Lys, adjusted OR=1.65, 95%CI=1.13–2.40, P=0.008). Subjects with the mutant homozygote variant (Gln/Gln) had a two fold increase in cancer risk (adjusted OR=2.18, 95%CI=1.06–4.47, p=0.028) when compared to the reference wild type genotype (Lys/Lys). Stratification by sex and age, identified males under 62 years as the most susceptible group with an almost three fold risk (adjusted OR=2.94, 95%CI=1.31–6.59, p=0.007) for the dominant model (Lys/Gln+Gln/Gln). No associations were found for TLR-4Thr399Ile, XRCC1Arg194Trp and XRCC1Arg399Gln. Conclusion: The results of the study show that the XPDLys751Gln polymorphism may be among other independent risk factors for developing laryngeal cancer where as TLR-4Thr399Ile, XRCC1Arg194Trp and XRCC1 Arg399Gln show no such association. However, we consider the relative small number of the subjects selected for this analyses a possible limitation towards the real influence the obtain results may pertain in laryngeal cancer evolution.
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8
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Barnett JT, Kuper J, Koelmel W, Kisker C, Kad NM. The TFIIH subunits p44/p62 act as a damage sensor during nucleotide excision repair. Nucleic Acids Res 2021; 48:12689-12696. [PMID: 33166411 PMCID: PMC7736792 DOI: 10.1093/nar/gkaa973] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 09/17/2020] [Accepted: 10/13/2020] [Indexed: 01/09/2023] Open
Abstract
Nucleotide excision repair (NER) in eukaryotes is orchestrated by the core form of the general transcription factor TFIIH, containing the helicases XPB, XPD and five ‘structural’ subunits, p62, p44, p34, p52 and p8. Recent cryo-EM structures show that p62 makes extensive contacts with p44 and in part occupies XPD’s DNA binding site. While p44 is known to regulate the helicase activity of XPD during NER, p62 is thought to be purely structural. Here, using helicase and adenosine triphosphatase assays we show that a complex containing p44 and p62 enhances XPD’s affinity for dsDNA 3-fold over p44 alone. Remarkably, the relative affinity is further increased to 60-fold by dsDNA damage. Direct binding studies show this preference derives from p44/p62’s high affinity (20 nM) for damaged ssDNA. Single molecule imaging of p44/p62 complexes without XPD reveals they bind to and randomly diffuse on DNA, however, in the presence of UV-induced DNA lesions these complexes stall. Combined with the analysis of a recent cryo-EM structure, we suggest that p44/p62 acts as a novel DNA-binding entity that enhances damage recognition in TFIIH. This revises our understanding of TFIIH and prompts investigation into the core subunits for an active role during DNA repair and/or transcription.
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Affiliation(s)
- Jamie T Barnett
- School of Biological Sciences, University of Kent, Canterbury CT2 7NH, UK
| | - Jochen Kuper
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Wolfgang Koelmel
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Caroline Kisker
- Rudolf Virchow Center for Integrative and Translational Bioimaging, Institute for Structural Biology, University of Würzburg, 97080 Würzburg, Germany
| | - Neil M Kad
- School of Biological Sciences, University of Kent, Canterbury CT2 7NH, UK
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9
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Sanles-Falagan R, Petrovic-Stojanovska B, White MF. Facile and scalable expression and purification of transcription factor IIH (TFIIH) core complex. Protein Expr Purif 2020; 174:105660. [PMID: 32473323 DOI: 10.1016/j.pep.2020.105660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
Abstract
Transcription factor IIH (TFIIH) plays essential roles in both the initiation of RNA Polymerase II-mediated transcription and the Nucleotide Excision Repair (NER) pathway in eukaryotes. In NER, the 7-subunit TFIIH Core sub-complex is responsible for the opening and extension of the DNA bubble created at the lesion site, utilizing the molecular motors XPB and XPD. Mutations in Core subunits are associated with a series of severe autosomal recessive disorders characterised by symptoms such as mild-to-extreme photosensitivity, premature ageing, physical and neurological anomalies, and in some cases an increased susceptibility to cancer. Although TFIIH Core has been successfully obtained in the past, the process has always remained challenging and laborious, involving many steps that severely hindered the amount of pure, active complex obtained. This has limited biochemical and functional studies of the NER process. Here we describe improved and simplified processes for the cloning, expression and purification of the 7-subunit TFIIH Core sub-complex. The combined use of auto-cleavable 2A-like sequences derived from the Foot-and-Mouth Disease Virus (FMDV) and the MultiBac™ cloning system, a powerful baculoviral expression vector specifically conceived for the obtaining of multi-subunit eukaryotic complexes, allowed us to obtain a single, 7-gene plasmid in a short time using regular restriction cloning strategies. Additionally, expression of the construct in High Five™ insect cells paired with a simple 5-step purification protocol allowed the extraction of a pure, active TFIIH Core sub-complex in milligram quantities.
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Affiliation(s)
- Reyes Sanles-Falagan
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, KY16 9ST, UK
| | | | - Malcolm F White
- Biomedical Sciences Research Complex, School of Biology, University of St Andrews, St Andrews, KY16 9ST, UK.
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10
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Kolesnikova O, Radu L, Poterszman A. TFIIH: A multi-subunit complex at the cross-roads of transcription and DNA repair. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 115:21-67. [PMID: 30798933 DOI: 10.1016/bs.apcsb.2019.01.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Transcription factor IIH (TFIIH) is a multiprotein complex involved in both eukaryotic transcription and DNA repair, revealing a tight connection between these two processes. Composed of 10 subunits, it can be resolved into a 7-subunits core complex with the XPB translocase and the XPD helicase, and the 3-subunits kinase complex CAK, which also exists as a free complex with a distinct function. Initially identified as basal transcription factor, TFIIH also participates in transcription regulation and plays a key role in nucleotide excision repair (NER) for opening DNA at damaged sites, lesion verification and recruitment of additional repair factors. Our understanding of TFIIH function in eukaryotic cells has greatly benefited from studies of the genetic rare diseases xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD), that are not only characterized by cancer and aging predispositions but also by neurological and developmental defects. Although much remains unknown about TFIIH function, significant progresses have been done regarding the structure of the complex, the functions of its catalytic subunits and the multiple roles of the regulatory core-TFIIH subunits. This review provides a non-exhaustive survey of key discoveries on the structure and function of this pivotal factor, which can be considered as a promising target for therapeutic strategies.
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Affiliation(s)
- Olga Kolesnikova
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Laura Radu
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Arnaud Poterszman
- Institut de Génétique et de Biologie Moléculaire et Cellulaire Illkirch Cedex, C.U. Strasbourg, France; Centre National de la Recherche Scientifique, UMR7104, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U1258, Illkirch, France; Université de Strasbourg, Illkirch, France.
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11
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Greber BJ, Nogales E. The Structures of Eukaryotic Transcription Pre-initiation Complexes and Their Functional Implications. Subcell Biochem 2019; 93:143-192. [PMID: 31939151 DOI: 10.1007/978-3-030-28151-9_5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transcription is a highly regulated process that supplies living cells with coding and non-coding RNA molecules. Failure to properly regulate transcription is associated with human pathologies, including cancers. RNA polymerase II is the enzyme complex that synthesizes messenger RNAs that are then translated into proteins. In spite of its complexity, RNA polymerase requires a plethora of general transcription factors to be recruited to the transcription start site as part of a large transcription pre-initiation complex, and to help it gain access to the transcribed strand of the DNA. This chapter reviews the structure and function of these eukaryotic transcription pre-initiation complexes, with a particular emphasis on two of its constituents, the multisubunit complexes TFIID and TFIIH. We also compare the overall architecture of the RNA polymerase II pre-initiation complex with those of RNA polymerases I and III, involved in transcription of ribosomal RNA and non-coding RNAs such as tRNAs and snRNAs, and discuss the general, conserved features that are applicable to all eukaryotic RNA polymerase systems.
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Affiliation(s)
- Basil J Greber
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Eva Nogales
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA
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12
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Hanske J, Sadian Y, Müller CW. The cryo-EM resolution revolution and transcription complexes. Curr Opin Struct Biol 2018; 52:8-15. [PMID: 30015202 PMCID: PMC6302067 DOI: 10.1016/j.sbi.2018.07.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 06/25/2018] [Accepted: 07/02/2018] [Indexed: 01/22/2023]
Abstract
Direct electron detector technology combined with improved imaging processing procedures has dramatically increased the resolution that can be obtained by single-particle cryo-electron microscopy and cryo-electron tomography. These developments-often referred to as the `resolution revolution' in cryo-EM-have had a profound impact on the structural biology of transcription as they allow the determination of atomic or near-atomic resolution structures of very large, flexible and often transient transcription complexes that in many cases had resisted crystal structure determination for decades. In this review, we will discuss recent advances and breakthroughs in the structural biology of transcription complexes enabled by the revolution in cryo-electron microscopy with particular focus on eukaryotic RNA polymerases and their pre-initiation complexes, but also chromatin remodelers and epigenetic regulators.
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Affiliation(s)
- Jonas Hanske
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Yashar Sadian
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Christoph W Müller
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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13
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Rimel JK, Taatjes DJ. The essential and multifunctional TFIIH complex. Protein Sci 2018; 27:1018-1037. [PMID: 29664212 PMCID: PMC5980561 DOI: 10.1002/pro.3424] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 12/19/2022]
Abstract
TFIIH is a 10‐subunit complex that regulates RNA polymerase II (pol II) transcription but also serves other important biological roles. Although much remains unknown about TFIIH function in eukaryotic cells, much progress has been made even in just the past few years, due in part to technological advances (e.g. cryoEM and single molecule methods) and the development of chemical inhibitors of TFIIH enzymes. This review focuses on the major cellular roles for TFIIH, with an emphasis on TFIIH function as a regulator of pol II transcription. We describe the structure of TFIIH and its roles in pol II initiation, promoter‐proximal pausing, elongation, and termination. We also discuss cellular roles for TFIIH beyond transcription (e.g. DNA repair, cell cycle regulation) and summarize small molecule inhibitors of TFIIH and diseases associated with defects in TFIIH structure and function.
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Affiliation(s)
- Jenna K Rimel
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
| | - Dylan J Taatjes
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado, 80303
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14
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Liu X, Salokas K, Tamene F, Jiu Y, Weldatsadik RG, Öhman T, Varjosalo M. An AP-MS- and BioID-compatible MAC-tag enables comprehensive mapping of protein interactions and subcellular localizations. Nat Commun 2018; 9:1188. [PMID: 29568061 PMCID: PMC5864832 DOI: 10.1038/s41467-018-03523-2] [Citation(s) in RCA: 154] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/21/2018] [Indexed: 11/09/2022] Open
Abstract
Protein-protein interactions govern almost all cellular functions. These complex networks of stable and transient associations can be mapped by affinity purification mass spectrometry (AP-MS) and complementary proximity-based labeling methods such as BioID. To exploit the advantages of both strategies, we here design and optimize an integrated approach combining AP-MS and BioID in a single construct, which we term MAC-tag. We systematically apply the MAC-tag approach to 18 subcellular and 3 sub-organelle localization markers, generating a molecular context database, which can be used to define a protein’s molecular location. In addition, we show that combining the AP-MS and BioID results makes it possible to obtain interaction distances within a protein complex. Taken together, our integrated strategy enables the comprehensive mapping of the physical and functional interactions of proteins, defining their molecular context and improving our understanding of the cellular interactome. AP-MS and BioID provide complementary insights into cellular protein interaction networks. To facilitate their combined use, the authors here present an AP-MS- and BioID-compatible affinity tag, enabling efficient determination of cellular protein locations and interaction distances.
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Affiliation(s)
- Xiaonan Liu
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland
| | - Kari Salokas
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland
| | - Fitsum Tamene
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland.,Proteomics Unit, University of Helsinki, Helsinki, 00014, Finland
| | - Yaming Jiu
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland
| | - Rigbe G Weldatsadik
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland.,Proteomics Unit, University of Helsinki, Helsinki, 00014, Finland
| | - Tiina Öhman
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland.,Proteomics Unit, University of Helsinki, Helsinki, 00014, Finland
| | - Markku Varjosalo
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland. .,Helsinki Institute of Life Science, University of Helsinki, Helsinki, 00014, Finland. .,Proteomics Unit, University of Helsinki, Helsinki, 00014, Finland.
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15
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Kahanda D, DuPrez KT, Hilario E, McWilliams MA, Wohlgamuth CH, Fan L, Slinker JD. Application of Electrochemical Devices to Characterize the Dynamic Actions of Helicases on DNA. Anal Chem 2018; 90:2178-2185. [PMID: 29285929 PMCID: PMC5957534 DOI: 10.1021/acs.analchem.7b04515] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Much remains to be understood about the kinetics and thermodynamics of DNA helicase binding and activity. Here, we utilize probe-modified DNA monolayers on multiplexed gold electrodes as a sensitive recognition element and morphologically responsive transducer of helicase-DNA interactions. The electrochemical signals from these devices are highly sensitive to structural distortion of the DNA produced by the helicases. We used this DNA electrochemistry to distinguish the details of the DNA interactions of three distinct XPB helicases, which belong to the superfamily-2 of helicases. Clear changes in DNA melting temperature and duplex stability were observed upon helicase binding, shifts that could not be observed with conventional UV-visible absorption measurements. Binding dissociation constants were estimated in the range from 10 to 50 nM and correlated with observations of activity. ATP-stimulated DNA unwinding activity was also followed, revealing exponential time scales and distinct time constants associated with conventional and molecular wrench modes of operation further confirmed by crystal structures. These devices thus provide a sensitive measure of the structural thermodynamics and kinetics of helicase-DNA interactions.
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Affiliation(s)
- Dimithree Kahanda
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, PHY 36, Richardson, Texas 75080, United States
| | - Kevin T. DuPrez
- Department of Biochemistry, University of California, 900 University Avenue, Riverside, California 92521, United States
| | - Eduardo Hilario
- Department of Biochemistry, University of California, 900 University Avenue, Riverside, California 92521, United States
| | - Marc A. McWilliams
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, PHY 36, Richardson, Texas 75080, United States
| | - Chris H. Wohlgamuth
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, PHY 36, Richardson, Texas 75080, United States
| | - Li Fan
- Department of Biochemistry, University of California, 900 University Avenue, Riverside, California 92521, United States
| | - Jason D. Slinker
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, PHY 36, Richardson, Texas 75080, United States
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16
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Schilbach S, Hantsche M, Tegunov D, Dienemann C, Wigge C, Urlaub H, Cramer P. Structures of transcription pre-initiation complex with TFIIH and Mediator. Nature 2017; 551:204-209. [PMID: 29088706 PMCID: PMC6078178 DOI: 10.1038/nature24282] [Citation(s) in RCA: 183] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 09/14/2017] [Indexed: 12/18/2022]
Abstract
For the initiation of transcription, RNA polymerase II (Pol II) assembles with general transcription factors on promoter DNA to form the pre-initiation complex (PIC). Here we report cryo-electron microscopy structures of the Saccharomyces cerevisiae PIC and PIC-core Mediator complex at nominal resolutions of 4.7 Å and 5.8 Å, respectively. The structures reveal transcription factor IIH (TFIIH), and suggest how the core and kinase TFIIH modules function in the opening of promoter DNA and the phosphorylation of Pol II, respectively. The TFIIH core subunit Ssl2 (a homologue of human XPB) is positioned on downstream DNA by the 'E-bridge' helix in TFIIE, consistent with TFIIE-stimulated DNA opening. The TFIIH kinase module subunit Tfb3 (MAT1 in human) anchors the kinase Kin28 (CDK7), which is mobile in the PIC but preferentially located between the Mediator hook and shoulder in the PIC-core Mediator complex. Open spaces between the Mediator head and middle modules may allow access of the kinase to its substrate, the C-terminal domain of Pol II.
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Affiliation(s)
- S Schilbach
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - M Hantsche
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - D Tegunov
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - C Dienemann
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - C Wigge
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - H Urlaub
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics Group, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - P Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
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17
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Rasheed M, Shahzad S, Zaeem A, Afzal I, Gul A, Khalid S. Updated strategies for the management, pathogenesis and molecular genetics of different forms of ichthyosis syndromes with prominent hair abnormalities. Arch Dermatol Res 2017; 309:773-785. [PMID: 28913623 DOI: 10.1007/s00403-017-1780-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/12/2017] [Accepted: 09/08/2017] [Indexed: 10/18/2022]
Abstract
Syndromic ichthyosis is rare inherited disorders of cornification with varied disease complications. This disorder appears in seventeen subtypes associated with severe systematic manifestations along with medical, cosmetic and social problems. Syndromic ichthyosis with prominent hair abnormalities covers five major subtypes: Netherton syndrome, trichothiodystrophy, ichthyosis hypotrichosis syndrome, ichthyosis hypotrichosis sclerosing cholangitis and ichthyosis follicularis atrichia photophobia syndrome. These syndromes mostly prevail in high consanguinity states, with distinctive clinical features. The known pathogenic molecules involved in ichthyosis syndromes with prominent hair abnormalities include SPINK5, ERCC2, ERCC3, GTF2H5, MPLKIP, ST14, CLDN1 and MBTPS2. Despite underlying genetic origin, most of the health professionals solely rely on phenotypic expression of these disorders that leads to improper management of patients, hence making these patients living an orphanage life. After dermal features, association of other systems such as nervous system, skeletal system, hair abnormalities or liver problems may sometimes give clues for diagnosis but still leaving place for molecular screening for efficient diagnosis. In this paper, we have presented a review of ichthyosis syndrome with prominent hair abnormalities, with special emphasis on their updated genetic consequences and disease management. Additionally, we aim to update health professionals about the practice of molecular screening in ichthyosis syndromes for appropriate diagnosis and treatment.
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Affiliation(s)
- Madiha Rasheed
- Department of Bioinformatics and Biotechnology, Maryum Block, International Islamic University Islamabad, H-10, Islamabad, 44000, Pakistan
| | - Shaheen Shahzad
- Department of Bioinformatics and Biotechnology, Maryum Block, International Islamic University Islamabad, H-10, Islamabad, 44000, Pakistan.
| | - Afifa Zaeem
- Department of Bioinformatics and Biotechnology, Maryum Block, International Islamic University Islamabad, H-10, Islamabad, 44000, Pakistan
| | - Imran Afzal
- Department of Biology, Lahore Garrison University, Lahore, Pakistan
| | - Asma Gul
- Department of Bioinformatics and Biotechnology, Maryum Block, International Islamic University Islamabad, H-10, Islamabad, 44000, Pakistan
| | - Sumbal Khalid
- Department of Bioinformatics and Biotechnology, Maryum Block, International Islamic University Islamabad, H-10, Islamabad, 44000, Pakistan
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18
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The cryo-electron microscopy structure of human transcription factor IIH. Nature 2017; 549:414-417. [PMID: 28902838 DOI: 10.1038/nature23903] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/10/2017] [Indexed: 02/04/2023]
Abstract
Human transcription factor IIH (TFIIH) is part of the general transcriptional machinery required by RNA polymerase II for the initiation of eukaryotic gene transcription. Composed of ten subunits that add up to a molecular mass of about 500 kDa, TFIIH is also essential for nucleotide excision repair. The seven-subunit TFIIH core complex formed by XPB, XPD, p62, p52, p44, p34, and p8 is competent for DNA repair, while the CDK-activating kinase subcomplex, which includes the kinase activity of CDK7 as well as the cyclin H and MAT1 subunits, is additionally required for transcription initiation. Mutations in the TFIIH subunits XPB, XPD, and p8 lead to severe premature ageing and cancer propensity in the genetic diseases xeroderma pigmentosum, Cockayne syndrome, and trichothiodystrophy, highlighting the importance of TFIIH for cellular physiology. Here we present the cryo-electron microscopy structure of human TFIIH at 4.4 Å resolution. The structure reveals the molecular architecture of the TFIIH core complex, the detailed structures of its constituent XPB and XPD ATPases, and how the core and kinase subcomplexes of TFIIH are connected. Additionally, our structure provides insight into the conformational dynamics of TFIIH and the regulation of its activity.
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19
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Abstract
Eukaryotic gene transcription requires the assembly at the promoter of a large preinitiation complex (PIC) that includes RNA polymerase II (Pol II) and the general transcription factors TFIID, TFIIA, TFIIB, TFIIF, TFIIE, and TFIIH. The size and complexity of Pol II, TFIID, and TFIIH have precluded their reconstitution from heterologous systems, and purification relies on scarce endogenous sources. Together with their conformational flexibility and the transient nature of their interactions, these limitations had precluded structural characterization of the PIC. In the last few years, however, progress in cryo-electron microscopy (cryo-EM) has made possible the visualization, at increasingly better resolution, of large PIC assemblies in different functional states. These structures can now be interpreted in near-atomic detail and provide an exciting structural framework for past and future functional studies, giving us unique mechanistic insight into the complex process of transcription initiation.
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Affiliation(s)
- Eva Nogales
- Molecular and Cell Biology Department and QB3 Institute, University of California, Berkeley, California 94720-3220
- Howard Hughes Medical Institute, Berkeley, California 94720-3220
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Lab, California 94720-3220;
| | - Robert K Louder
- Biophysics Graduate Group, University of California, Berkeley, California 94720-3220
| | - Yuan He
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208-3500
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20
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MacroBac: New Technologies for Robust and Efficient Large-Scale Production of Recombinant Multiprotein Complexes. Methods Enzymol 2017; 592:1-26. [PMID: 28668116 DOI: 10.1016/bs.mie.2017.03.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recombinant expression of large, multiprotein complexes is essential and often rate limiting for determining structural, biophysical, and biochemical properties of DNA repair, replication, transcription, and other key cellular processes. Baculovirus-infected insect cell expression systems are especially well suited for producing large, human proteins recombinantly, and multigene baculovirus systems have facilitated studies of multiprotein complexes. In this chapter, we describe a multigene baculovirus system called MacroBac that uses a Biobricks-type assembly method based on restriction and ligation (Series 11) or ligation-independent cloning (Series 438). MacroBac cloning and assembly is efficient and equally well suited for either single subcloning reactions or high-throughput cloning using 96-well plates and liquid handling robotics. MacroBac vectors are polypromoter with each gene flanked by a strong polyhedrin promoter and an SV40 poly(A) termination signal that minimize gene order expression level effects seen in many polycistronic assemblies. Large assemblies are robustly achievable, and we have successfully assembled as many as 10 genes into a single MacroBac vector. Importantly, we have observed significant increases in expression levels and quality of large, multiprotein complexes using a single, multigene, polypromoter virus rather than coinfection with multiple, single-gene viruses. Given the importance of characterizing functional complexes, we believe that MacroBac provides a critical enabling technology that may change the way that structural, biophysical, and biochemical research is done.
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21
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Function of Conserved Topological Regions within the Saccharomyces cerevisiae Basal Transcription Factor TFIIH. Mol Cell Biol 2016; 36:2464-75. [PMID: 27381459 DOI: 10.1128/mcb.00182-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/30/2016] [Indexed: 11/20/2022] Open
Abstract
TFIIH is a 10-subunit RNA polymerase II basal transcription factor with a dual role in DNA repair. TFIIH contains three enzymatic functions and over 30 conserved subdomains and topological regions. We systematically tested the function of these regions in three TFIIH core module subunits, i.e., Ssl1, Tfb4, and Tfb2, in the DNA translocase subunit Ssl2, and in the kinase module subunit Tfb3. Our results are consistent with previously predicted roles for the Tfb2 Hub, Ssl2 Lock, and Tfb3 Latch regions, with mutations in these elements typically having severe defects in TFIIH subunit association. We also found unexpected roles for other domains whose function had not previously been defined. First, the Ssl1-Tfb4 Ring domains are important for TFIIH assembly. Second, the Tfb2 Hub and HEAT domains have an unexpected role in association with Tfb3. Third, the Tfb3 Ring domain is important for association with many other TFIIH subunits. Fourth, a partial deletion of the Ssl1 N-terminal extension (NTE) domain inhibits TFIIH function without affecting subunit association. Finally, we used site-specific cross-linking to localize the Tfb3-binding surface on the Rad3 Arch domain. Our cross-linking results suggest that Tfb3 and Rad3 have an unusual interface, with Tfb3 binding on two opposite faces of the Arch.
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22
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Compe E, Egly JM. Nucleotide Excision Repair and Transcriptional Regulation: TFIIH and Beyond. Annu Rev Biochem 2016; 85:265-90. [DOI: 10.1146/annurev-biochem-060815-014857] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de Strasbourg, 67404 Illkirch Cedex, Commune Urbaine Strasbourg, France; ,
| | - Jean-Marc Egly
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de Strasbourg, 67404 Illkirch Cedex, Commune Urbaine Strasbourg, France; ,
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23
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Dedecker M, Van Leene J, De Winne N, Eeckhout D, Persiau G, Van De Slijke E, Cannoot B, Vercruysse L, Dumoulin L, Wojsznis N, Gevaert K, Vandenabeele S, De Jaeger G. Transferring an optimized TAP-toolbox for the isolation of protein complexes to a portfolio of rice tissues. PLANT MOLECULAR BIOLOGY 2016; 91:341-354. [PMID: 27003905 DOI: 10.1007/s11103-016-0471-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 03/10/2016] [Indexed: 06/05/2023]
Abstract
Proteins are the cell's functional entities. Rather than operating independently, they interact with other proteins. Capturing in vivo protein complexes is therefore crucial to gain understanding of the function of a protein in a cellular context. Affinity purification coupled to mass spectrometry has proven to yield a wealth of information about protein complex constitutions for a broad range of organisms. For Oryza sativa, the technique has been initiated in callus and shoots, but has not been optimized ever since. We translated an optimized tandem affinity purification (TAP) approach from Arabidopsis thaliana toward Oryza sativa, and demonstrate its applicability in a variety of rice tissues. A list of non-specific and false positive interactors is presented, based on re-occurrence over more than 170 independent experiments, to filter bona fide interactors. We demonstrate the sensitivity of our approach by isolating the complexes for the rice ANAPHASE PROMOTING COMPLEX SUBUNIT 10 (APC10) and CYCLIN-DEPENDENT KINASE D (CDKD) proteins from the proliferation zone of the emerging fourth leaf. Next to APC10 and CDKD, we tested several additional baits in the different rice tissues and reproducibly retrieved at least one interactor for 81.4 % of the baits screened for in callus tissue and T1 seedlings. By transferring an optimized TAP tag combined with state-of-the-art mass spectrometry, our TAP protocol enables the discovery of interactors for low abundance proteins in rice and opens the possibility to capture complex dynamics by comparing tissues at different stages of a developing rice organ.
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Affiliation(s)
- Maarten Dedecker
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium.
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium.
- CropDesign N.V., Technologiepark 21, 9052, Ghent, Belgium.
| | - Jelle Van Leene
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Nancy De Winne
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Dominique Eeckhout
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Geert Persiau
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Eveline Van De Slijke
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Bernard Cannoot
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Leen Vercruysse
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium
| | - Lies Dumoulin
- CropDesign N.V., Technologiepark 21, 9052, Ghent, Belgium
| | | | - Kris Gevaert
- Department of Medical Protein Research and Biochemistry, VIB, Albert Baertsoenkaai 3, 9000, Ghent, Belgium
- Department of Biochemistry, Ghent University, Albert Baertsoenkaai 3, 9000, Ghent, Belgium
| | | | - Geert De Jaeger
- Department of Plant Systems Biology, VIB, Technologiepark 927, 9052, Ghent, Belgium.
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium.
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Sugitani N, Sivley RM, Perry KE, Capra JA, Chazin WJ. XPA: A key scaffold for human nucleotide excision repair. DNA Repair (Amst) 2016; 44:123-135. [PMID: 27247238 DOI: 10.1016/j.dnarep.2016.05.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nucleotide excision repair (NER) is essential for removing many types of DNA lesions from the genome, yet the mechanisms of NER in humans remain poorly understood. This review summarizes our current understanding of the structure, biochemistry, interaction partners, mechanisms, and disease-associated mutations of one of the critical NER proteins, XPA.
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Affiliation(s)
- Norie Sugitani
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Robert M Sivley
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Kelly E Perry
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - John A Capra
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States
| | - Walter J Chazin
- Departments of Biochemistry, Biological Sciences, Biomedical Informatics, Chemistry, and Computer Science, and Vanderbilt Genetics Institute and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-7917, United States.
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25
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Abstract
XPD, as part of the TFIIH complex, has classically been linked to the damage verification step of nucleotide excision repair (NER). However, recent data indicate that XPD, due to its iron-sulfur center interacts with the iron sulfur cluster assembly proteins, and may interact with other proteins in the cell to mediate a diverse set of biological functions including cell cycle regulation, mitosis, and mitochondrial function. In this perspective, after first reviewing the function and some of the key disease causing variants that affect XPD's interaction with TFIIH and the CDK-activating kinase complex (CAK), we investigate these intriguing cellular roles of XPD and highlight important unanswered questions that provide a fertile ground for further scientific exploration.
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Affiliation(s)
- Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
| | - Jochen Kuper
- Rudolf-Virchow-Center for Experimental Biomedicine, University of Wuerzburg, Wuerzburg, Germany.
| | - Caroline Kisker
- Rudolf-Virchow-Center for Experimental Biomedicine, University of Wuerzburg, Wuerzburg, Germany.
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26
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He Y, Yan C, Fang J, Inouye C, Tjian R, Ivanov I, Nogales E. Near-atomic resolution visualization of human transcription promoter opening. Nature 2016; 533:359-65. [PMID: 27193682 PMCID: PMC4940141 DOI: 10.1038/nature17970] [Citation(s) in RCA: 213] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 04/05/2016] [Indexed: 12/11/2022]
Abstract
In eukaryotic transcription initiation, a large multi-subunit pre-initiation complex (PIC) that assembles at the core promoter is required for the opening of the duplex DNA and identification of the start site for transcription by RNA polymerase II. Here we use cryo-electron microscropy (cryo-EM) to determine near-atomic resolution structures of the human PIC in a closed state (engaged with duplex DNA), an open state (engaged with a transcription bubble), and an initially transcribing complex (containing six base pairs of DNA-RNA hybrid). Our studies provide structures for previously uncharacterized components of the PIC, such as TFIIE and TFIIH, and segments of TFIIA, TFIIB and TFIIF. Comparison of the different structures reveals the sequential conformational changes that accompany the transition from each state to the next throughout the transcription initiation process. This analysis illustrates the key role of TFIIB in transcription bubble stabilization and provides strong structural support for a translocase activity of XPB.
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Affiliation(s)
- Yuan He
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Chunli Yan
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302, USA
| | - Jie Fang
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA
| | - Carla Inouye
- Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, California 94720, USA
| | - Robert Tjian
- Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.,Li Ka Shing Center for Biomedical and Health Sciences, University of California, Berkeley, California 94720, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Ivaylo Ivanov
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30302, USA
| | - Eva Nogales
- Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Howard Hughes Medical Institute, University of California, Berkeley, California 94720, USA.,Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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27
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Tripartite DNA Lesion Recognition and Verification by XPC, TFIIH, and XPA in Nucleotide Excision Repair. Mol Cell 2015; 59:1025-34. [PMID: 26384665 DOI: 10.1016/j.molcel.2015.08.012] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/09/2015] [Accepted: 08/17/2015] [Indexed: 11/23/2022]
Abstract
Transcription factor IIH (TFIIH) is essential for both transcription and nucleotide excision repair (NER). DNA lesions are initially detected by NER factors XPC and XPE or stalled RNA polymerases, but only bulky lesions are preferentially repaired by NER. To elucidate substrate specificity in NER, we have prepared homogeneous human ten-subunit TFIIH and its seven-subunit core (Core7) without the CAK module and show that bulky lesions in DNA inhibit the ATPase and helicase activities of both XPB and XPD in Core7 to promote NER, whereas non-genuine NER substrates have no such effect. Moreover, the NER factor XPA activates unwinding of normal DNA by Core7, but inhibits the Core7 helicase activity in the presence of bulky lesions. Finally, the CAK module inhibits DNA binding by TFIIH and thereby enhances XPC-dependent specific recruitment of TFIIH. Our results support a tripartite lesion verification mechanism involving XPC, TFIIH, and XPA for efficient NER.
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28
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Luo J, Cimermancic P, Viswanath S, Ebmeier CC, Kim B, Dehecq M, Raman V, Greenberg CH, Pellarin R, Sali A, Taatjes DJ, Hahn S, Ranish J. Architecture of the Human and Yeast General Transcription and DNA Repair Factor TFIIH. Mol Cell 2015; 59:794-806. [PMID: 26340423 DOI: 10.1016/j.molcel.2015.07.016] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 06/10/2015] [Accepted: 07/17/2015] [Indexed: 10/23/2022]
Abstract
TFIIH is essential for both RNA polymerase II transcription and DNA repair, and mutations in TFIIH can result in human disease. Here, we determine the molecular architecture of human and yeast TFIIH by an integrative approach using chemical crosslinking/mass spectrometry (CXMS) data, biochemical analyses, and previously published electron microscopy maps. We identified four new conserved "topological regions" that function as hubs for TFIIH assembly and more than 35 conserved topological features within TFIIH, illuminating a network of interactions involved in TFIIH assembly and regulation of its activities. We show that one of these conserved regions, the p62/Tfb1 Anchor region, directly interacts with the DNA helicase subunit XPD/Rad3 in native TFIIH and is required for the integrity and function of TFIIH. We also reveal the structural basis for defects in patients with xeroderma pigmentosum and trichothiodystrophy, with mutations found at the interface between the p62 Anchor region and the XPD subunit.
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Affiliation(s)
- Jie Luo
- Institute for Systems Biology, 401 Terry Avenue North, Seattle, WA 98109, USA
| | - Peter Cimermancic
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Shruthi Viswanath
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Christopher C Ebmeier
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Bong Kim
- Institute for Systems Biology, 401 Terry Avenue North, Seattle, WA 98109, USA
| | - Marine Dehecq
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, PO Box 19024, Mailstop A1-162, Seattle, WA 98109, USA; Génétique des Interactions Macromoléculaires, Institut Pasteur, CNRS UMR3525, 25-28 rue du docteur Roux, 75015 Paris, France
| | - Vishnu Raman
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Charles H Greenberg
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Riccardo Pellarin
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, California Institute for Quantitative Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Dylan J Taatjes
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Steven Hahn
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, PO Box 19024, Mailstop A1-162, Seattle, WA 98109, USA
| | - Jeff Ranish
- Institute for Systems Biology, 401 Terry Avenue North, Seattle, WA 98109, USA.
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29
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Uncoupling Promoter Opening from Start-Site Scanning. Mol Cell 2015; 59:133-8. [PMID: 26073544 DOI: 10.1016/j.molcel.2015.05.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/08/2015] [Accepted: 05/08/2015] [Indexed: 01/24/2023]
Abstract
Whereas RNA polymerase II (Pol II) transcription start sites (TSSs) occur about 30-35 bp downstream of the TATA box in metazoans, TSSs are located 40-120 bp downstream in S. cerevisiae. Promoter melting begins about 12 bp downstream in all eukaryotes, so Pol II is presumed to "scan" further downstream before starting transcription in yeast. Here we report that removal of the kinase complex TFIIK from TFIIH shifts the TSS in a yeast system upstream to the location observed in metazoans. Conversely, moving the normal TSS to an upstream location enables a high level of TFIIK-independent transcription in the yeast system. We distinguish two stages of the transcription initiation process: bubble formation by TFIIH, which fills the Pol II active center with single-stranded DNA, and subsequent scanning downstream, also driven by TFIIH, which requires displacement of the initial bubble. Omission of TFIIK uncouples the two stages of the process.
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30
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Tajedin L, Anwar M, Gupta D, Tuteja R. Comparative insight into nucleotide excision repair components of Plasmodium falciparum. DNA Repair (Amst) 2015; 28:60-72. [PMID: 25757193 DOI: 10.1016/j.dnarep.2015.02.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 01/27/2015] [Accepted: 02/10/2015] [Indexed: 12/19/2022]
Abstract
Nucleotide excision repair (NER) is one of the DNA repair pathways crucial for maintenance of genome integrity and deals with repair of DNA damages arising due to exogenous and endogenous factors. The multi-protein transcription initiation factor TFIIH plays a critical role in NER and transcription and is highly conserved throughout evolution. The malaria parasite Plasmodium falciparum has been a challenge for the researchers for a long time because of emergence of drug resistance. The availability of its genome sequence has opened new avenues for research. Antimalarial drugs like chloroquine and mefloquine have been reported to inhibit NER pathway mediated repair reactions and thus promote mutagenesis. Previous studies have validated existence and implied possible association of defective or altered DNA repair pathways with development of drug resistant phenotype in certain P. falciparum strains. We conjecture that a compromised NER pathway in combination with other DNA repair pathways might be conducive for the emergence and sustenance of drug resistance in P. falciparum. Therefore we decided to unravel the components of NER pathway in P. falciparum and using bioinformatics based approaches here we report a genome wide in silico analysis of NER components from P. falciparum and their comparison with the human host. Our results reveal that P. falciparum genome contains almost all the components of NER but we were unable to find clear homologue for p62 and XPC in its genome. The structure modeling of all the components further suggests that their structures are significantly conserved. Furthermore this study lays a foundation to perform similar comparative studies between drug resistant and drug sensitive strains of parasite in order to understand DNA repair-related mechanisms of drug resistance.
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Affiliation(s)
- Leila Tajedin
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Masroor Anwar
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Dinesh Gupta
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Renu Tuteja
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
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31
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Abstract
Transcription of eukaryotic protein-coding genes commences with the assembly of a conserved initiation complex, which consists of RNA polymerase II (Pol II) and the general transcription factors, at promoter DNA. After two decades of research, the structural basis of transcription initiation is emerging. Crystal structures of many components of the initiation complex have been resolved, and structural information on Pol II complexes with general transcription factors has recently been obtained. Although mechanistic details await elucidation, available data outline how Pol II cooperates with the general transcription factors to bind to and open promoter DNA, and how Pol II directs RNA synthesis and escapes from the promoter.
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32
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Kim JS, Saint-André C, Lim HS, Hwang CS, Egly JM, Cho Y. Crystal structure of the Rad3/XPD regulatory domain of Ssl1/p44. J Biol Chem 2015; 290:8321-30. [PMID: 25681444 DOI: 10.1074/jbc.m115.636514] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The Ssl1/p44 subunit is a core component of the yeast/mammalian general transcription factor TFIIH, which is involved in transcription and DNA repair. Ssl1/p44 binds to and stimulates the Rad3/XPD helicase activity of TFIIH. To understand the helicase stimulatory mechanism of Ssl1/p44, we determined the crystal structure of the N-terminal regulatory domain of Ssl1 from Saccharomyces cerevisiae. Ssl1 forms a von Willebrand factor A fold in which a central six-stranded β-sheet is sandwiched between three α helices on both sides. Structural and biochemical analyses of Ssl1/p44 revealed that the β4-α5 loop, which is frequently found at the interface between von Willebrand factor A family proteins and cellular counterparts, is critical for the stimulation of Rad3/XPD. Yeast genetics analyses showed that double mutation of Leu-239 and Ser-240 in the β4-α5 loop of Ssl1 leads to lethality of a yeast strain, demonstrating the importance of the Rad3-Ssl1 interactions to cell viability. Here, we provide a structural model for the Rad3/XPD-Ssl1/p44 complex and insights into how the binding of Ssl1/p44 contributes to the helicase activity of Rad3/XPD and cell viability.
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Affiliation(s)
- Jin Seok Kim
- From the Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea and
| | - Charlotte Saint-André
- the Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/UdS, BP163, 67404 Illkirch Cedex, C.U. Strasbourg, France
| | - Hye Seong Lim
- From the Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea and
| | - Cheol-Sang Hwang
- From the Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea and
| | - Jean Marc Egly
- the Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/UdS, BP163, 67404 Illkirch Cedex, C.U. Strasbourg, France
| | - Yunje Cho
- From the Department of Life Science, Pohang University of Science and Technology, Pohang 790-784, South Korea and
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33
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Fan L, DuPrez KT. XPB: An unconventional SF2 DNA helicase. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 117:174-181. [PMID: 25641424 DOI: 10.1016/j.pbiomolbio.2014.12.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/24/2014] [Accepted: 12/29/2014] [Indexed: 11/27/2022]
Abstract
XPB is a 3'-5' DNA helicase belonging to the superfamily 2 (SF2) of helicases. XPB is an essential core subunit of the eukaryotic basal transcription factor complex TFIIH which plays a dual role in transcription and DNA repair: 1) to facilitate the melting of the promoter during the initiation of RNA polymerase II transcription; 2) to unwind double stranded DNA (dsDNA) around a DNA lesion during nucleotide excision repair (NER). NER is a highly versatile DNA repair process which is able to remove a broad spectrum of structurally unrelated DNA helix-distorting lesions. The importance of a fully functional XPB is clearly illustrated by the severe clinical consequences associated with inherited defects in XPB including UV-hypersensitive syndromes xeroderma pigmentosum (XP), Cockayne syndrome (CS), combined XP and CS (XP/CS), and trichothiodystrophy (TTD). Here we discuss the structure and function of XPB in NER as well as the impact of a disease mutation in XP11BE patients with XP/CS complex manifestations.
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Affiliation(s)
- Li Fan
- 900 University Ave, Biochemistry Department, University of California, Riverside, CA 92521, USA.
| | - Kevin T DuPrez
- 900 University Ave, Biochemistry Department, University of California, Riverside, CA 92521, USA
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34
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Stettler K, Li X, Sandrock B, Braga-Lagache S, Heller M, Dümbgen L, Suter B. A Drosophila XPD model links cell cycle coordination with neuro-development and suggests links to cancer. Dis Model Mech 2014; 8:81-91. [PMID: 25431422 PMCID: PMC4283652 DOI: 10.1242/dmm.016907] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
XPD functions in transcription, DNA repair and in cell cycle control. Mutations in human XPD (also known as ERCC2) mainly cause three clinical phenotypes: xeroderma pigmentosum (XP), Cockayne syndrome (XP/CS) and trichothiodystrophy (TTD), and only XP patients have a high predisposition to developing cancer. Hence, we developed a fly model to obtain novel insights into the defects caused by individual hypomorphic alleles identified in human XP-D patients. This model revealed that the mutations that displayed the greatest in vivo UV sensitivity in Drosophila did not correlate with those that led to tumor formation in humans. Immunoprecipitations followed by targeted quantitative MS/MS analysis showed how different xpd mutations affected the formation or stability of different transcription factor IIH (TFIIH) subcomplexes. The XP mutants most clearly linked to high cancer risk, Xpd R683W and R601L, showed a reduced interaction with the core TFIIH and also an abnormal interaction with the Cdk-activating kinase (CAK) complex. Interestingly, these two XP alleles additionally displayed high levels of chromatin loss and free centrosomes during the rapid nuclear division phase of the Drosophila embryo. Finally, the xpd mutations showing defects in the coordination of cell cycle timing during the Drosophila embryonic divisions correlated with those human mutations that cause the neurodevelopmental abnormalities and developmental growth defects observed in XP/CS and TTD patients.
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Affiliation(s)
- Karin Stettler
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Xiaoming Li
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Björn Sandrock
- Department of Biology, Philipps-University Marburg, 35032 Marburg, Germany
| | | | - Manfred Heller
- Department of Clinical Research, University of Bern, 3010 Bern, Switzerland
| | - Lutz Dümbgen
- Institute of Mathematical Statistics and Actuarial Science, University of Bern, 3012 Bern, Switzerland
| | - Beat Suter
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland.
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35
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36
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Schmitt DR, Kuper J, Elias A, Kisker C. The structure of the TFIIH p34 subunit reveals a von Willebrand factor A like fold. PLoS One 2014; 9:e102389. [PMID: 25013903 PMCID: PMC4094531 DOI: 10.1371/journal.pone.0102389] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 06/19/2014] [Indexed: 11/19/2022] Open
Abstract
RNA polymerase II dependent transcription and nucleotide excision repair are mediated by a multifaceted interplay of subunits within the general transcription factor II H (TFIIH). A better understanding of the molecular structure of TFIIH is the key to unravel the mechanism of action of this versatile protein complex within these vital cellular processes. The importance of this complex becomes further evident in the context of severe diseases like xeroderma pigmentosum, Cockayne's syndrome and trichothiodystrophy, that arise from single point mutations in TFIIH subunits. Here we describe the structure of the p34 subunit of the TFIIH complex from the eukaryotic thermophilic fungus Chaetomium thermophilum. The structure revealed that p34 contains a von Willebrand Factor A (vWA) like domain, a fold which is generally known to be involved in protein-protein interactions. Within TFIIH p34 strongly interacts with p44, a positive regulator of the helicase XPD. Putative protein-protein interfaces are analyzed and possible binding sites for the p34-p44 interaction suggested.
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Affiliation(s)
- Dominik R. Schmitt
- Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Jochen Kuper
- Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Agnes Elias
- Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Wuerzburg, Wuerzburg, Germany
| | - Caroline Kisker
- Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Wuerzburg, Wuerzburg, Germany
- * E-mail:
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37
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Moslehi R, Ambroggio X, Nagarajan V, Kumar A, Dzutsev A. Nucleotide excision repair/transcription gene defects in the fetus and impaired TFIIH-mediated function in transcription in placenta leading to preeclampsia. BMC Genomics 2014; 15:373. [PMID: 24885447 PMCID: PMC4229886 DOI: 10.1186/1471-2164-15-373] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 05/06/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Preeclampsia is a significant cause of maternal and fetal mortality and morbidity worldwide. We previously reported associations between trichothiodystrophy (TTD) nucleotide excision repair (NER) and transcription gene mutations in the fetus and the risk of gestational complications including preeclampsia. TTD NER/transcription genes, XPD, XPB and TTD-A, code for subunits of Transcription Factor (TF)IIH. Interpreting XPD mutations in the context of available biochemical data led us to propose adverse effects on CDK-activating kinase (CAK) subunit of TFIIH and TFIIH-mediated functions as a relevant mechanism in preeclampsia. In order to gain deeper insight into the underlying biologic mechanisms involving TFIIH-mediated functions in placenta, we analyzed NER/transcription and global gene expression profiles of normal and preeclamptic placentas and studied gene regulatory networks. RESULTS We found high expression of TTD NER/transcription genes in normal human placenta, above the mean of their expression in all organs. XPD and XPB were consistently expressed from 14 to 40 weeks gestation while expression of TTD-A was strongly negatively correlated (r=-0.7, P<0.0001) with gestational age. Analysis of gene expression patterns of placentas from a case-control study of preeclampsia using Algorithm for Reconstruction of Accurate Cellular Networks (ARACNE) revealed GTF2E1, a component of TFIIE which modulates TFIIH, among major regulators of differentially-expressed genes in preeclampsia. The basal transcription pathway was among the largest dysregulated protein-protein interaction networks in this preeclampsia dataset. Within the basal transcription pathway, significantly down-regulated genes besides GTF2E1 included those coding for the CAK complex of TFIIH, namely CDK7, CCNH, and MNAT1. Analysis of other relevant gene expression and gene regulatory network data also underscored the involvement of transcription pathways and identified JUNB and JUND (components of transcription factor AP-1) as transcription regulators of the network involving the TTD genes, GTF2E1, and selected gene regulators implicated in preeclampsia. CONCLUSIONS Our results indicate that TTD NER/transcription genes are expressed in placenta during gestational periods critical to preeclampsia development. Our overall findings suggest that impairment of TFIIH-mediated function in transcription in placenta is a likely mechanism leading to preeclampsia and provide etiologic clues which may be translated into therapeutic and preventive measures.
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Affiliation(s)
- Roxana Moslehi
- Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, State University of New York (SUNY), Rensselaer, NY 12144, USA.
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38
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Silva IAL, Cox CJ, Leite RB, Cancela ML, Conceição N. Evolutionary conservation of TFIIH subunits: implications for the use of zebrafish as a model to study TFIIH function and regulation. Comp Biochem Physiol B Biochem Mol Biol 2014; 172-173:9-20. [PMID: 24731924 DOI: 10.1016/j.cbpb.2014.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 11/28/2022]
Abstract
Transcriptional factor IIH (TFIIH) is involved in cell cycle regulation, nucleotide excision repair, and gene transcription. Mutations in three of its subunits, XPB, XPD, and TTDA, lead to human recessive genetic disorders such as trichothiodystrophy and xeroderma pigmentosum, the latter of which is sometimes associated with Cockayne's syndrome. In the present study, we investigate the sequence conservation of TFIIH subunits among several teleost fish species and compare their characteristics and putative regulation by transcription factors to those of human and zebrafish. We report the following findings: (i) comparisons among protein sequences revealed a high sequence identity for each TFIIH subunit analysed; (ii) among transcription factors identified as putative regulators, OCT1 and AP1 have the highest binding-site frequencies in the promoters of TFIIH genes, and (iii) TFIIH genes have alternatively spliced isoforms. Finally, we compared the protein primary structure in human and zebrafish of XPD and XPB - two important ATP-dependent helicases that catalyse the unwinding of the DNA duplex at promoters during transcription - highlighting the conservation of domain regions such as the helicase domains. Our study suggests that zebrafish, a widely used model for many human diseases, could also act as an important model to study the function of TFIIH complex in repair and transcription regulation in humans.
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Affiliation(s)
- I A L Silva
- Department of Biomedical Sciences and Medicine, University of Algarve, Faro, Portugal; Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - C J Cox
- Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - R B Leite
- Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - M L Cancela
- Department of Biomedical Sciences and Medicine, University of Algarve, Faro, Portugal; Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal
| | - N Conceição
- Centre of Marine Sciences (CCMAR), University of Algarve, Faro, Portugal.
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39
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Abstract
Solar ultraviolet (UV) radiation, mainly UV-B (280-315 nm), is one of the most potent genotoxic agents that adversely affects living organisms by altering their genomic stability. DNA through its nucleobases has absorption maxima in the UV region and is therefore the main target of the deleterious radiation. The main biological relevance of UV radiation lies in the formation of several cytotoxic and mutagenic DNA lesions such as cyclobutane pyrimidine dimers (CPDs), 6-4 photoproducts (6-4PPs), and their Dewar valence isomers (DEWs), as well as DNA strand breaks. However, to counteract these DNA lesions, organisms have developed a number of highly conserved repair mechanisms such as photoreactivation, excision repair, and mismatch repair (MMR). Photoreactivation involving the enzyme photolyase is the most frequently used repair mechanism in a number of organisms. Excision repair can be classified as base excision repair (BER) and nucleotide excision repair (NER) involving a number of glycosylases and polymerases, respectively. In addition to this, double-strand break repair, SOS response, cell-cycle checkpoints, and programmed cell death (apoptosis) are also operative in various organisms to ensure genomic stability. This review concentrates on the UV-induced DNA damage and the associated repair mechanisms as well as various damage detection methods.
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Affiliation(s)
- Richa
- Laboratory of Photobiology and Molecular Microbiology, Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi, 221005, India
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Murakami K, Elmlund H, Kalisman N, Bushnell DA, Adams CM, Azubel M, Elmlund D, Levi-Kalisman Y, Liu X, Levitt M, Kornberg RD, Gibbons BJ. Architecture of an RNA polymerase II transcription pre-initiation complex. Science 2013; 342:1238724. [PMID: 24072820 PMCID: PMC4039082 DOI: 10.1126/science.1238724] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The protein density and arrangement of subunits of a complete, 32-protein, RNA polymerase II (pol II) transcription pre-initiation complex (PIC) were determined by means of cryogenic electron microscopy and a combination of chemical cross-linking and mass spectrometry. The PIC showed a marked division in two parts, one containing all the general transcription factors (GTFs) and the other pol II. Promoter DNA was associated only with the GTFs, suspended above the pol II cleft and not in contact with pol II. This structural principle of the PIC underlies its conversion to a transcriptionally active state; the PIC is poised for the formation of a transcription bubble and descent of the DNA into the pol II cleft.
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Affiliation(s)
- Kenji Murakami
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Hans Elmlund
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Nir Kalisman
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - David A. Bushnell
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Christopher M. Adams
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA 94305, U.S.A
| | - Maia Azubel
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Dominika Elmlund
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Yael Levi-Kalisman
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Xin Liu
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Michael Levitt
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Roger D. Kornberg
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
| | - Brian J. Gibbons
- Department of Structural Biology, Stanford University, Stanford, CA 94305, U.S.A
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Lihoradova OA, Indran SV, Kalveram B, Lokugamage N, Head JA, Gong B, Tigabu B, Juelich TL, Freiberg AN, Ikegami T. Characterization of Rift Valley fever virus MP-12 strain encoding NSs of Punta Toro virus or sandfly fever Sicilian virus. PLoS Negl Trop Dis 2013; 7:e2181. [PMID: 23638202 PMCID: PMC3630143 DOI: 10.1371/journal.pntd.0002181] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 03/15/2013] [Indexed: 12/22/2022] Open
Abstract
Rift Valley fever virus (RVFV; genus Phlebovirus, family Bunyaviridae) is a mosquito-borne zoonotic pathogen which can cause hemorrhagic fever, neurological disorders or blindness in humans, and a high rate of abortion in ruminants. MP-12 strain, a live-attenuated candidate vaccine, is attenuated in the M- and L-segments, but the S-segment retains the virulent phenotype. MP-12 was manufactured as an Investigational New Drug vaccine by using MRC-5 cells and encodes a functional NSs gene, the major virulence factor of RVFV which 1) induces a shutoff of the host transcription, 2) inhibits interferon (IFN)-β promoter activation, and 3) promotes the degradation of dsRNA-dependent protein kinase (PKR). MP-12 lacks a marker for differentiation of infected from vaccinated animals (DIVA). Although MP-12 lacking NSs works for DIVA, it does not replicate efficiently in type-I IFN-competent MRC-5 cells, while the use of type-I IFN-incompetent cells may negatively affect its genetic stability. To generate modified MP-12 vaccine candidates encoding a DIVA marker, while still replicating efficiently in MRC-5 cells, we generated recombinant MP-12 encoding Punta Toro virus Adames strain NSs (rMP12-PTNSs) or Sandfly fever Sicilian virus NSs (rMP12-SFSNSs) in place of MP-12 NSs. We have demonstrated that those recombinant MP-12 viruses inhibit IFN-β mRNA synthesis, yet do not promote the degradation of PKR. The rMP12-PTNSs, but not rMP12-SFSNSs, replicated more efficiently than recombinant MP-12 lacking NSs in MRC-5 cells. Mice vaccinated with rMP12-PTNSs or rMP12-SFSNSs induced neutralizing antibodies at a level equivalent to those vaccinated with MP-12, and were efficiently protected from wild-type RVFV challenge. The rMP12-PTNSs and rMP12-SFSNSs did not induce antibodies cross-reactive to anti-RVFV NSs antibody and are therefore applicable to DIVA. Thus, rMP12-PTNSs is highly efficacious, replicates efficiently in MRC-5 cells, and encodes a DIVA marker, all of which are important for vaccine development for Rift Valley fever. Upon outbreak of zoonotic viral diseases in herds of animals, early detection of naturally infected animals and prevention of further viral spread are important for minimizing the impact of outbreak in the society. Vaccination may compromise the identification of infected animals since both natural infection and vaccination induce antibodies specific to the pathogen. Therefore, new generation vaccines should have a marker to differentiate infected from vaccinated animals (DIVA). Rift Valley fever virus (RVFV) is a mosquito-borne zoonotic pathogen which can cause hemorrhagic fever, neurological disorders or blindness in humans and a high-rate abortion in ruminants. MP-12 strain, a live-attenuated candidate vaccine, is safe and immunogenic, but lacks a DIVA marker. In this study, we developed and characterized improved MP-12 viruses which encode a DIVA marker by replacing the virulence gene with that of serologically distinct viruses belonging to the same genera. The novel MP-12 variant with such DIVA marker was highly efficacious and replicated efficiently in human diploid cells for vaccine production, and will become alternative candidate vaccines of MP-12 for veterinary applications.
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Affiliation(s)
- Olga A. Lihoradova
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Sabarish V. Indran
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Birte Kalveram
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Nandadeva Lokugamage
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Jennifer A. Head
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Bin Gong
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Bersabeh Tigabu
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Terry L. Juelich
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Alexander N. Freiberg
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Galveston National Laboratory, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Center for Vaccine Development, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Tetsuro Ikegami
- Department of Pathology, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Sealy Center for Vaccine Development, The University of Texas Medical Branch, Galveston, Texas, United States of America
- Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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42
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ARCH domain of XPD, an anchoring platform for CAK that conditions TFIIH DNA repair and transcription activities. Proc Natl Acad Sci U S A 2013; 110:E633-42. [PMID: 23382212 DOI: 10.1073/pnas.1213981110] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The xeroderma pigmentosum group D (XPD) helicase is a subunit of transcription/DNA repair factor, transcription factor II H (TFIIH) that catalyzes the unwinding of a damaged DNA duplex during nucleotide excision repair. Apart from two canonical helicase domains, XPD is composed of a 4Fe-S cluster domain involved in DNA damage recognition and a module of uncharacterized function termed the "ARCH domain." By investigating the consequences of a mutation found in a patient with trichothiodystrophy, we show that the ARCH domain is critical for the recruitment of the cyclin-dependent kinase (CDK)-activating kinase (CAK) complex. Indeed, this mutation not only affects the interaction with the MAT1 CAK subunit, thereby decreasing the in vitro basal transcription activity of TFIIH itself and impeding the efficient recruitment of the transcription machinery on the promoter of an activated gene, but also impairs the DNA unwinding activity of XPD and the nucleotide excision repair activity of TFIIH. We further demonstrate the role of CAK in downregulating the XPD helicase activity within TFIIH. Taken together, our results identify the ARCH domain of XPD as a platform for the recruitment of CAK and as a potential molecular switch that might control TFIIH composition and play a key role in the conversion of TFIIH from a factor active in transcription to a factor involved in DNA repair.
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43
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Hilario E, Li Y, Nobumori Y, Liu X, Fan L. Structure of the C-terminal half of human XPB helicase and the impact of the disease-causing mutation XP11BE. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:237-46. [PMID: 23385459 DOI: 10.1107/s0907444912045040] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 10/30/2012] [Indexed: 01/26/2023]
Abstract
XPB is a DNA-dependent helicase and a subunit of the TFIIH complex required for both transcription and DNA repair. XPB contains four domains: an N-terminal domain, two conserved helicase domains (HD1 and HD2) and a C-terminal extension. The C-terminal extension is important for DNA repair since the phosphorylation of Ser751 inhibits 5'-incision by ERCC1-XPF endonuclease. A disease-causing frameshift mutation (XP11BE) that changes the last 42 amino acids of XPB causes manifestations including impaired DNA repair and deficient transcription. Here, the crystal structure of the C-terminal half of XPB (residues 494-782) is reported at 1.8 Å resolution. The structure contained the conserved XPB HD2 and a C-terminal extension which shares structural similarity with RIG-I, leading to a structural model of the XPF-XPB-DNA complex for 5' incision during DNA repair. A mutation mimicking the XP11BE mutation produced the much less soluble mutant XPBm(494-781). Western blotting results confirmed that the intracellular levels of XPB and other TFIIH subunits in XP11BE patient cells were much lower than those from the healthy parents. Together, these results indicate that the XP11BE mutation not only divests the XPF-interaction motif, impairing DNA repair, but also reduces XPB solubility, leading to a lower intracellular level of TFIIH and deficient transcription.
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Affiliation(s)
- Eduardo Hilario
- Department of Biochemistry, University of California, Riverside, Riverside, CA 92521, USA
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44
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Abstract
The transcription initiation factor TFIIH is a remarkable protein complex that has a fundamental role in the transcription of protein-coding genes as well as during the DNA nucleotide excision repair pathway. The detailed understanding of how TFIIH functions to coordinate these two processes is also providing an explanation for the phenotypes observed in patients who bear mutations in some of the TFIIH subunits. In this way, studies of TFIIH have revealed tight molecular connections between transcription and DNA repair and have helped to define the concept of 'transcription diseases'.
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Affiliation(s)
- Emmanuel Compe
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/UdS, BP 163, 67404 Illkirch Cedex, C. U., Strasbourg, France.
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45
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The dominant-negative inhibition of double-stranded RNA-dependent protein kinase PKR increases the efficacy of Rift Valley fever virus MP-12 vaccine. J Virol 2012; 86:7650-61. [PMID: 22573861 DOI: 10.1128/jvi.00778-12] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rift Valley fever virus (RVFV), belonging to the genus Phlebovirus, family Bunyaviridae, is endemic to sub-Saharan Africa and causes a high rate of abortion in ruminants and hemorrhagic fever, encephalitis, or blindness in humans. MP-12 is the only RVFV strain excluded from the select-agent rule and handled at a biosafety level 2 (BSL2) laboratory. MP-12 encodes a functional major virulence factor, the NSs protein, which contributes to its residual virulence in pregnant ewes. We found that 100% of mice subcutaneously vaccinated with recombinant MP-12 (rMP12)-murine PKRN167 (mPKRN167), which encodes a dominant-negative form of mouse double-stranded RNA (dsRNA)-dependent protein kinase (PKR) in place of NSs, were protected from wild-type (wt) RVFV challenge, while 72% of mice vaccinated with MP-12 were protected after challenge. rMP12-mPKRN167 induced alpha interferon (IFN-α) in sera, accumulated RVFV antigens in dendritic cells at the local draining lymph nodes, and developed high levels of neutralizing antibodies, while parental MP-12 induced neither IFN-α nor viral-antigen accumulation at the draining lymph node yet induced a high level of neutralizing antibodies. The present study suggests that the expression of a dominant-negative PKR increases the immunogenicity and efficacy of live-attenuated RVFV vaccine, which will lead to rational design of safe and highly immunogenic RVFV vaccines for livestock and humans.
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46
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Abstract
Structures of complete 10-subunit yeast TFIIH and of a nested set of subcomplexes, containing 5, 6, and 7 subunits, have been determined by electron microscopy (EM) and 3D reconstruction. Consistency among all the structures establishes the location of the "minimal core" subunits (Ssl1, Tfb1, Tfb2, Tfb4, and Tfb5), and additional densities can be specifically attributed to Rad3, Ssl2, and the TFIIK trimer. These results can be further interpreted by placement of previous X-ray structures into the additional densities to give a preliminary picture of the RNA polymerase II preinitiation complex. In this picture, the key catalytic components of TFIIH, the Ssl2 ATPase/helicase and the Kin28 protein kinase are in proximity to their targets, downstream promoter DNA and the RNA polymerase C-terminal domain.
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Moslehi R, Kumar A, Mills JL, Ambroggio X, Signore C, Dzutsev A. Phenotype-specific adverse effects of XPD mutations on human prenatal development implicate impairment of TFIIH-mediated functions in placenta. Eur J Hum Genet 2012; 20:626-31. [PMID: 22234153 DOI: 10.1038/ejhg.2011.249] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mutations in XPD (ERCC2), XPB (ERCC3), and TTD-A (GTF2H5), genes involved in nucleotide excision repair and transcription, can cause several disorders including trichothiodystrophy (TTD) and xeroderma pigmentosum (XP). In this study, we tested the hypothesis that mutations in the XPD gene affect placental development in a phenotype-specific manner. To test our hypothesis and decipher potential biologic mechanisms, we compared all XPD-associated TTD (n=43) and XP (n=37) cases reported in the literature with respect to frequencies of gestational complications. Our genetic epidemiologic investigations of TTD and XP revealed that the exact genetic abnormality was relevant to the mechanism leading to gestational complications such as preeclampsia. Through structural mapping, we localized the preeclampsia-associated mutations to a C-terminal motif and the helicase surfaces of XPD, most likely affecting XPD's binding to cdk-activating kinase (CAK) and p44 subunits of transcription factor (TF) IIH. Our results suggested a link between TTD- but not XP-associated XPD mutations, placental maldevelopment and risk of pregnancy complications, possibly due to impairment of TFIIH-mediated functions in placenta. Our findings highlight the importance of the fetal genotype in development of gestational complications, such as preeclampsia. Therefore, future studies of genetic associations of preeclampsia and other placental vascular complications may benefit from focusing on genetic variants within the fetal DNA.
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Affiliation(s)
- Roxana Moslehi
- Department of Epidemiology and Biostatistics, School of Public Health, University at Albany, Albany, NY 12144, USA.
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49
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Egly JM, Coin F. A history of TFIIH: two decades of molecular biology on a pivotal transcription/repair factor. DNA Repair (Amst) 2011; 10:714-21. [PMID: 21592869 DOI: 10.1016/j.dnarep.2011.04.021] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The TFIIH multiprotein complex is organized into a 7-subunit core associated with a 3-subunit CDK-activating kinase module (CAK). Three enzymatic subunits are present in TFIIH, two ATP-dependent DNA helicases: XPB and XPD, and the kinase Cdk7. Mutations in three of the subunits, XPB, XPD and TTDA, lead to three distinct genetic disorders: xeroderma pigmentosum (XP), Cockayne syndrome (CS) and trichothiodystrophy (TTD) predisposing patients not only to cancer and ageing but also to developmental and neurological defects. These heterogeneous phenotypes originate from the dual role of TFIIH in transcription and DNA repair. For twenty years, many molecular studies have been conducted with the aim to unveil the role of TFIIH in DNA repair and transcription as well as the origin of the phenotypes of patients. This review intends to give a non-exhaustive survey of the most prominent discoveries on the molecular functioning of TFIIH.
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Affiliation(s)
- Jean-Marc Egly
- IGBMC, Program of Functional Genomics and Cancer, CNRS/INSERM/ULP, BP 163, 67404 Illkirch Cedex, C.U. Strasbourg, France.
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50
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Fuss JO, Tainer JA. XPB and XPD helicases in TFIIH orchestrate DNA duplex opening and damage verification to coordinate repair with transcription and cell cycle via CAK kinase. DNA Repair (Amst) 2011; 10:697-713. [PMID: 21571596 DOI: 10.1016/j.dnarep.2011.04.028] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Helicases must unwind DNA at the right place and time to maintain genomic integrity or gene expression. Biologically critical XPB and XPD helicases are key members of the human TFIIH complex; they anchor CAK kinase (cyclinH, MAT1, CDK7) to TFIIH and open DNA for transcription and for repair of duplex distorting damage by nucleotide excision repair (NER). NER is initiated by arrested RNA polymerase or damage recognition by XPC-RAD23B with or without DDB1/DDB2. XP helicases, named for their role in the extreme sun-mediated skin cancer predisposition xeroderma pigmentosum (XP), are then recruited to asymmetrically unwind dsDNA flanking the damage. XPB and XPD genetic defects can also cause premature aging with profound neurological defects without increased cancers: Cockayne syndrome (CS) and trichothiodystrophy (TTD). XP helicase patient phenotypes cannot be predicted from the mutation position along the linear gene sequence and adjacent mutations can cause different diseases. Here we consider the structural biology of DNA damage recognition by XPC-RAD23B, DDB1/DDB2, RNAPII, and ATL, and of helix unwinding by the XPB and XPD helicases plus the bacterial repair helicases UvrB and UvrD in complex with DNA. We then propose unified models for TFIIH assembly and roles in NER. Collective crystal structures with NMR and electron microscopy results reveal functional motifs, domains, and architectural elements that contribute to biological activities: damaged DNA binding, translocation, unwinding, and ATP driven changes plus TFIIH assembly and signaling. Coupled with mapping of patient mutations, these combined structural analyses provide a framework for integrating and unifying the rich biochemical and cellular information that has accumulated over forty years of study. This integration resolves puzzles regarding XP helicase functions and suggests that XP helicase positions and activities within TFIIH detect and verify damage, select the damaged strand for incision, and coordinate repair with transcription and cell cycle through CAK signaling.
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Affiliation(s)
- Jill O Fuss
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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