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Yang L, Yang Q, Wang M, Jia R, Chen S, Zhu D, Liu M, Wu Y, Zhao X, Zhang S, Liu Y, Yu Y, Zhang L, Chen X, Cheng A. Terminase Large Subunit Provides a New Drug Target for Herpesvirus Treatment. Viruses 2019; 11:v11030219. [PMID: 30841485 PMCID: PMC6466031 DOI: 10.3390/v11030219] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 12/26/2022] Open
Abstract
Herpesvirus infection is an orderly, regulated process. Among these viruses, the encapsidation of viral DNA is a noteworthy link; the entire process requires a powered motor that binds to viral DNA and carries it into the preformed capsid. Studies have shown that this power motor is a complex composed of a large subunit, a small subunit, and a third subunit, which are collectively known as terminase. The terminase large subunit is highly conserved in herpesvirus. It mainly includes two domains: the C-terminal nuclease domain, which cuts the viral concatemeric DNA into a monomeric genome, and the N-terminal ATPase domain, which hydrolyzes ATP to provide energy for the genome cutting and transfer activities. Because this process is not present in eukaryotic cells, it provides a reliable theoretical basis for the development of safe and effective anti-herpesvirus drugs. This article reviews the genetic characteristics, protein structure, and function of the herpesvirus terminase large subunit, as well as the antiviral drugs that target the terminase large subunit. We hope to provide a theoretical basis for the prevention and treatment of herpesvirus.
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Affiliation(s)
- Linlin Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yunya Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Yanling Yu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Xiaoyue Chen
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Research Center of Avian Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, China.
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu 611130, Sichuan, China.
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Piret J, Boivin G. Clinical development of letermovir and maribavir: Overview of human cytomegalovirus drug resistance. Antiviral Res 2019; 163:91-105. [PMID: 30690043 DOI: 10.1016/j.antiviral.2019.01.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/28/2023]
Abstract
The prevention and treatment of human cytomegalovirus (HCMV) infections is based on the use of antiviral agents that currently target the viral DNA polymerase and that may cause serious side effects. The search for novel inhibitors against HCMV infection led to the discovery of new molecular targets, the viral terminase complex and the viral pUL97 kinase. The most advanced compounds consist of letermovir (LMV) and maribavir (MBV). LMV inhibits the cleavage of viral DNA and its packaging into capsids by targeting the HCMV terminase complex. LMV is safe and well tolerated and exhibits pharmacokinetic properties that allow once daily dosing. LMV showed efficacy in a phase III prophylaxis study in hematopoietic stem cell transplant (HSCT) recipients seropositive for HCMV. LMV was recently approved under the trade name Prevymis™ for prophylaxis of HCMV infection in adult seropositive recipients of an allogeneic HSCT. Amino acid substitutions conferring resistance to LMV selected in vitro map primarily to the pUL56 and rarely to the pUL89 and pUL51 subunits of the HCMV terminase complex. MBV is an inhibitor of the viral pUL97 kinase activity and interferes with the morphogenesis and nuclear egress of nascent viral particles. MBV is safe and well tolerated and has an excellent oral bioavailability. MBV was effective for the treatment of HCMV infections (including those that are refractory or drug-resistant) in transplant recipients in two phase II studies and is further evaluated in two phase III trials. Mutations conferring resistance to MBV map to the UL97 gene and can cause cross-resistance to ganciclovir. MBV-resistant mutations also emerged in the UL27 gene in vitro and could compensate for the inhibition of pUL97 kinase activity by MBV. Thus, LMV and probably MBV will broaden the armamentarium of antiviral drugs available for the prevention and treatment of HCMV infections.
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Affiliation(s)
- Jocelyne Piret
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada
| | - Guy Boivin
- Research Center in Infectious Diseases, CHU of Quebec and Laval University, Quebec City, QC, Canada.
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3
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FRET-based assay using a three-way junction DNA substrate to identify inhibitors of human cytomegalovirus pUL89 endonuclease activity. Eur J Pharm Sci 2019; 127:29-37. [DOI: 10.1016/j.ejps.2018.10.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023]
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Ligat G, Cazal R, Hantz S, Alain S. The human cytomegalovirus terminase complex as an antiviral target: a close-up view. FEMS Microbiol Rev 2018; 42:137-145. [PMID: 29361041 PMCID: PMC5972660 DOI: 10.1093/femsre/fuy004] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 01/17/2018] [Indexed: 01/13/2023] Open
Abstract
Human cytomegalovirus (HCMV) is responsible for life-threatening infections in immunocompromised individuals and can cause serious congenital malformations. Available antivirals target the viral polymerase but are subject to cross-resistance and toxicity. New antivirals targeting other replication steps and inducing fewer adverse effects are therefore needed. During HCMV replication, DNA maturation and packaging are performed by the terminase complex, which cleaves DNA to package the genome into the capsid. Identified in herpesviruses and bacteriophages, and with no counterpart in mammalian cells, these terminase proteins are ideal targets for highly specific antivirals. A new terminase inhibitor, letermovir, recently proved effective against HCMV in phase III clinical trials, but the mechanism of action is unclear. Letermovir has no significant activity against other herpesvirus or non-human CMV. This review focuses on the highly conserved mechanism of HCMV DNA-packaging and the potential of the terminase complex to serve as an antiviral target. We describe the intrinsic mechanism of DNA-packaging, highlighting the structure-function relationship of HCMV terminase complex components.
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Affiliation(s)
- G Ligat
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - R Cazal
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - S Hantz
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
| | - S Alain
- Université Limoges, INSERM, CHU Limoges, UMR 1092, 2 rue Dr Marcland, 87000 Limoges, France.,CHU Limoges, Laboratoire de Bactériologie-Virologie-Hygiène, National Reference Center for Herpesviruses (NRHV), 2 avenue Martin Luther King, 87000 Limoges, France
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5
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Gentry BG, Bogner E, Drach JC. Targeting the terminase: An important step forward in the treatment and prophylaxis of human cytomegalovirus infections. Antiviral Res 2018; 161:116-124. [PMID: 30472161 DOI: 10.1016/j.antiviral.2018.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/07/2018] [Accepted: 11/13/2018] [Indexed: 10/27/2022]
Abstract
A key step in the replication of human cytomegalovirus (HCMV) in the host cell is the generation and packaging of unit-length genomes into preformed capsids. Enzymes required for this process are so-called terminases, first described for double-stranded DNA bacteriophages. The HCMV terminase consists of the two subunits, the ATPase pUL56 and the nuclease pUL89, and a potential third component pUL51. The terminase subunits are essential for virus replication and are highly conserved throughout the Herpesviridae family. Together with the portal protein pUL104 they form a powerful biological nanomotor. It has been shown for tailed dsDNA bacteriophages that DNA translocation into preformed capsid needs an extraordinary amount of energy. The HCMV terminase subunit pUL56 provides the required ATP hydrolyzing activity. The necessary nuclease activity to cleave the concatemers into unit-length genomes is mediated by the terminase subunit pUL89. Whether this cleavage is mediated by site-specific duplex nicking has not been demonstrated, however, it is required for packaging. Binding to the portal is a prerequisite for DNA translocation. To date, it is a common view that during translocation the terminase moves along some domains of the DNA by a binding and release mechanism. These critical structures have proven to be outstanding targets for drugs to treat HCMV infections because corresponding structures do not exist in mammalian cells. Herein we examine the HCMV terminase as a target for drugs and review several inhibitors discovered by both lead-directed medicinal chemistry and by target-specific design. In addition to producing clinically active compounds the research also has furthered the understanding of the role and function of the terminase itself.
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Affiliation(s)
- Brian G Gentry
- Drake University College of Pharmacy and Health Sciences, 2507 University Ave., Des Moines, 50311, IA, USA.
| | - Elke Bogner
- Institute of Virology, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117, Berlin, Germany.
| | - John C Drach
- University of Michigan School of Dentistry, 1101 N. University Ave., Ann Arbor, 48109, MI, USA.
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6
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Bongarzone S, Nadal M, Kaczmarska Z, Machón C, Álvarez M, Albericio F, Coll M. Structure-Driven Discovery of α,γ-Diketoacid Inhibitors Against UL89 Herpesvirus Terminase. ACS OMEGA 2018; 3:8497-8505. [PMID: 31458978 PMCID: PMC6645139 DOI: 10.1021/acsomega.8b01472] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/19/2018] [Indexed: 05/27/2023]
Abstract
Human cytomegalovirus (HCMV) is an opportunistic pathogen causing a variety of severe viral infections, including irreversible congenital disabilities. Nowadays, HCMV infection is treated by inhibiting the viral DNA polymerase. However, DNA polymerase inhibitors have several drawbacks. An alternative strategy is to use compounds against the packaging machinery or terminase complex, which is essential for viral replication. Our discovery that raltegravir (1), a human immunodeficiency virus drug, inhibits the nuclease function of UL89, one of the protein subunits of the complex, prompted us to further develop terminase inhibitors. On the basis of the structure of 1, a library of diketoacid (α,γ-DKA and β,δ-DKA) derivatives were synthesized and tested for UL89-C nuclease activity. The mode of action of α,γ-DKA derivatives on the UL89 active site was elucidated by using X-ray crystallography, molecular docking, and in vitro experiments. Our studies identified α,γ-DKA derivative 14 able to inhibit UL89 in vitro in the low micromolar range, making 14 an optimal candidate for further development and virus-infected cell assay.
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Affiliation(s)
- Salvatore Bongarzone
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- Molecular
Biology Institute of Barcelona (IBMB—CSIC), Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Marta Nadal
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- Molecular
Biology Institute of Barcelona (IBMB—CSIC), Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Zuzanna Kaczmarska
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- Molecular
Biology Institute of Barcelona (IBMB—CSIC), Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Cristina Machón
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- Molecular
Biology Institute of Barcelona (IBMB—CSIC), Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain
| | - Mercedes Álvarez
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- CIBER-BBN,
Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Barcelona Science Park, 08028 Barcelona, Spain
- Laboratory
of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain
| | - Fernando Albericio
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- CIBER-BBN,
Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Barcelona Science Park, 08028 Barcelona, Spain
- Department
of Organic Chemistry, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Miquel Coll
- Institute
for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10-12, 08028 Barcelona, Spain
- Molecular
Biology Institute of Barcelona (IBMB—CSIC), Barcelona Science Park, Baldiri Reixac 10-12, 08028 Barcelona, Spain
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Metal-chelating 3-hydroxypyrimidine-2,4-diones inhibit human cytomegalovirus pUL89 endonuclease activity and virus replication. Antiviral Res 2018; 152:10-17. [DOI: 10.1016/j.antiviral.2018.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 01/22/2018] [Accepted: 01/31/2018] [Indexed: 11/17/2022]
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8
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Neuber S, Wagner K, Messerle M, Borst EM. The C-terminal part of the human cytomegalovirus terminase subunit pUL51 is central for terminase complex assembly. J Gen Virol 2018; 99:119-134. [DOI: 10.1099/jgv.0.000984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Sebastian Neuber
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Karen Wagner
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Martin Messerle
- Institute of Virology, Hannover Medical School, Hannover, Germany
| | - Eva Maria Borst
- Institute of Virology, Hannover Medical School, Hannover, Germany
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Comparison of Cytomegalovirus Terminase Gene Mutations Selected after Exposure to Three Distinct Inhibitor Compounds. Antimicrob Agents Chemother 2017; 61:AAC.01325-17. [PMID: 28827420 DOI: 10.1128/aac.01325-17] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/16/2017] [Indexed: 12/29/2022] Open
Abstract
Letermovir, GW275175X (a benzimidazole), and tomeglovir (Bay38-4766) are chemically unrelated human cytomegalovirus (CMV) terminase complex inhibitors that have been tested in human subjects. UL56 gene mutations are the dominant pathway of letermovir resistance, while UL89 and UL56 mutations are known to confer benzimidazole resistance. This study compares the mutations elicited by the three inhibitors during in vitro CMV propagation. GW275175X consistently selected for UL89 D344E and sometimes selected for UL89 C347S, UL89 R351H, or UL56 Q204R. Tomeglovir consistently selected for UL89 V362M and sometimes selected for UL89 N329S, T350M, H389N, or N405D or UL56 L208M, E407D, H637Q, or V639M. Adding to known and novel UL56 mutations, letermovir occasionally selected for UL89 N320H, D344E, or M359I. Recombinant phenotyping confirmed that UL89 D344E conferred 9-fold resistance (an increased 50% effective concentration [EC50]) for GW275175X and increased the letermovir and tomeglovir EC50s by 1.7- to 2.1-fold for the baseline virus and the UL56 Q204R, E237D, F261L, and M329T mutants. UL89 N320H and M359I conferred <2-fold letermovir resistance but 7-fold tomeglovir resistance; the N320H mutant was also 4-fold resistant to GW275175X. UL89 N329S conferred tomeglovir and letermovir cross-resistance. UL89 T350M conferred resistance to all three inhibitors. UL89 C347S conferred 27-fold GW275175X resistance. UL89 V362M and H389N conferred 98-fold and 29-fold tomeglovir resistance, respectively, without conferring cross-resistance. Thus, characteristic UL89 mutations confer substantial resistance to GW275175X and tomeglovir and are an uncommon accessory pathway of letermovir resistance. Instances of moderate cross-resistance and the proximity of the selected UL89 and UL56 mutations suggest targeting of a similar terminase functional locus involving UL56 and UL89 interaction.
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Mutual Interplay between the Human Cytomegalovirus Terminase Subunits pUL51, pUL56, and pUL89 Promotes Terminase Complex Formation. J Virol 2017; 91:JVI.02384-16. [PMID: 28356534 DOI: 10.1128/jvi.02384-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 03/17/2017] [Indexed: 01/05/2023] Open
Abstract
Human cytomegalovirus (HCMV) genome encapsidation requires several essential viral proteins, among them pUL56, pUL89, and the recently described pUL51, which constitute the viral terminase. To gain insight into terminase complex assembly, we investigated interactions between the individual subunits. For analysis in the viral context, HCMV bacterial artificial chromosomes carrying deletions in the open reading frames encoding the terminase proteins were used. These experiments were complemented by transient-transfection assays with plasmids expressing the terminase components. We found that if one terminase protein was missing, the levels of the other terminase proteins were markedly diminished, which could be overcome by proteasome inhibition or providing the missing subunit in trans These data imply that sequestration of the individual subunits within the terminase complex protects them from proteasomal turnover. The finding that efficient interactions among the terminase proteins occurred only when all three were present together is reminiscent of a folding-upon-binding principle leading to cooperative stability. Furthermore, whereas pUL56 was translocated into the nucleus on its own, correct nuclear localization of pUL51 and pUL89 again required all three terminase constituents. Altogether, these features point to a model of the HCMV terminase as a multiprotein complex in which the three players regulate each other concerning stability, subcellular localization, and assembly into the functional tripartite holoenzyme.IMPORTANCE HCMV is a major risk factor in immunocompromised individuals, and congenital CMV infection is the leading viral cause for long-term sequelae, including deafness and mental retardation. The current treatment of CMV disease is based on drugs sharing the same mechanism, namely, inhibiting viral DNA replication, and often results in adverse side effects and the appearance of resistant virus strains. Recently, the HCMV terminase has emerged as an auspicious target for novel antiviral drugs. A new drug candidate inhibiting the HCMV terminase, Letermovir, displayed excellent potency in clinical trials; however, its precise mode of action is not understood yet. Here, we describe the mutual dependence of the HCMV terminase constituents for their assembly into a functional terminase complex. Besides providing new basic insights into terminase formation, these results will be valuable when studying the mechanism of action for drugs targeting the HCMV terminase and developing additional substances interfering with viral genome encapsidation.
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11
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Sankhala RS, Lokareddy RK, Cingolani G. Divergent Evolution of Nuclear Localization Signal Sequences in Herpesvirus Terminase Subunits. J Biol Chem 2016; 291:11420-33. [PMID: 27033706 DOI: 10.1074/jbc.m116.724393] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Indexed: 11/06/2022] Open
Abstract
The tripartite terminase complex of herpesviruses assembles in the cytoplasm of infected cells and exploits the host nuclear import machinery to gain access to the nucleus, where capsid assembly and genome-packaging occur. Here we analyzed the structure and conservation of nuclear localization signal (NLS) sequences previously identified in herpes simplex virus 1 (HSV-1) large terminase and human cytomegalovirus (HCMV) small terminase. We found a monopartite NLS at the N terminus of large terminase, flanking the ATPase domain, that is conserved only in α-herpesviruses. In contrast, small terminase exposes a classical NLS at the far C terminus of its helical structure that is conserved only in two genera of the β-subfamily and absent in α- and γ-herpesviruses. In addition, we predicted a classical NLS in the third terminase subunit that is partially conserved among herpesviruses. Bioinformatic analysis revealed that both location and potency of NLSs in terminase subunits evolved more rapidly than the rest of the amino acid sequence despite the selective pressure to keep terminase gene products active and localized in the nucleus. We propose that swapping NLSs among terminase subunits is a regulatory mechanism that allows different herpesviruses to regulate the kinetics of terminase nuclear import, reflecting a mechanism of virus:host adaptation.
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Affiliation(s)
- Rajeshwer S Sankhala
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
| | - Ravi K Lokareddy
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and
| | - Gino Cingolani
- From the Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107 and Institute of Biomembranes and Bioenergetics, National Research Council, Via Amendola 165/A, 70126 Bari, Italy
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12
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Human cytomegalovirus (CMV) susceptibility to currently approved antiviral drugs does not impact on CMV terminase complex polymorphism. Antiviral Res 2014; 111:8-12. [DOI: 10.1016/j.antiviral.2014.08.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 08/08/2014] [Accepted: 08/13/2014] [Indexed: 11/22/2022]
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13
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Thoma C, Bogner E. Short hairpin RNAs specific to human cytomegalovirus terminase subunit pUL89 prevent viral maturation. Antivir Ther 2010; 15:391-400. [PMID: 20516558 DOI: 10.3851/imp1536] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND In order to define the role of the human cytomegalovirus (HCMV) small terminase subunit pUL89, analysis by RNA interference was applied. METHODS Cell lines expressing pUL89-specific short hairpin RNAs (shRNAs) were constructed by transduction of shRNAs via infection with retroviral vectors. These cell lines were infected with HCMV AD169 and were analysed for pUL89 expression, viral yield, plaque reduction, amount of viral DNA and particle formation. RESULTS After infection of the cell lines with HCMV, the expression of pUL89 was reduced by up to 86% for shRNA_A and 84% for shRNA_B at the later time points of infection. Cell lines expressing shRNA_C and the control had no effect on the pUL89 expression level. In addition, the inhibitory effect corresponded to a decrease in viral growth kinetics, viral DNA and plaque formation. Analysis by electron microscopy demonstrated that infection of cells expressing pUL89-specific shRNA_A and shRNA_B resulted in a complete inhibition of viral particle formation. CONCLUSIONS HCMV is a serious life-threatening opportunistic pathogen in immunocompromised patients. Because of multiple problems caused by the current available drugs, development of new strategies are needed. Our data clearly demonstrate that pUL89-specific shRNAs mediated the inhibition of formation of replicative infectious particles and therefore represent a new promising mechanism for antiviral therapy against HCMV infection.
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Affiliation(s)
- Corina Thoma
- Institute of Virology, Charité Universitâtsmedizin Berlin, Berlin, Germany
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Structure and inhibition of herpesvirus DNA packaging terminase nuclease domain. Proc Natl Acad Sci U S A 2010; 107:16078-83. [PMID: 20805464 DOI: 10.1073/pnas.1007144107] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During viral replication, herpesviruses package their DNA into the procapsid by means of the terminase protein complex. In human cytomegalovirus (herpesvirus 5), the terminase is composed of subunits UL89 and UL56. UL89 cleaves the long DNA concatemers into unit-length genomes of appropriate length for encapsidation. We used ESPRIT, a high-throughput screening method, to identify a soluble purifiable fragment of UL89 from a library of 18,432 randomly truncated ul89 DNA constructs. The purified protein was crystallized and its three-dimensional structure was solved. This protein corresponds to the key nuclease domain of the terminase and shows an RNase H/integrase-like fold. We demonstrate that UL89-C has the capacity to process the DNA and that this function is dependent on Mn(2+) ions, two of which are located at the active site pocket. We also show that the nuclease function can be inactivated by raltegravir, a recently approved anti-AIDS drug that targets the HIV integrase.
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Hantz S, Couvreux A, Champier G, Trapes L, Cotin S, Denis F, Bouaziz S, Alain S. Conserved domains and structure prediction of human cytomegalovirus UL27 protein. Antivir Ther 2009. [DOI: 10.1177/135965350901400510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background The human cytomegalovirus (HCMV) nuclear UL27 protein (pUL27) could be involved at the stage of nuclear egress. Maribavir is a new anti-HCMV drug that targets nuclear egress through direct inhibition of the HCMV serine–threonine kinase, UL97 protein (pUL97). Because maribavir- resistance-related mutations are observed in both proteins, pUL27 is thought to interfere with pUL97 activity; however, its mechanism of action remains unclear. Methods As there is no available crystal structure for pUL27 or any known structures of its homologous proteins, we attempted to identify pUL27 functional domains by sequence analysis, identification of conserved domains, structure prediction and matching with previously known maribavir resistance mutations. Results The UL27 sequence analysis of 20 HCMV wild-type strains and 8 ganciclovir-resistant HCMV strains allowed us to describe four conserved domains, to localize the putative phosphorylation sites and to identify protein–protein interface domains, suggesting that pUL27 could interact with either pUL97 or itself. Conclusions Although the function of pUL27 is still unknown in the HCMV replication cycle, our approach identified target domains that appeared to be essential to the function of pUL27. This work provides a better understanding on the relative importance of each pUL27 mutation and could form the basis of later comparison analyses, when a three-dimensional structure of a pUL27 homologue will be available.
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Affiliation(s)
- Sébastien Hantz
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
| | - Anthony Couvreux
- Unité de Pharmacologie Chimique & Génétique, Université Paris Descartes, INSERM, CNRS, UFR des Sciences Pharmaceutiques et Biologiques, Paris, France
| | - Gaël Champier
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
- SAS B Cell Design, Faculté de Médecine, Limoges, France
| | - Laurène Trapes
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
| | - Sébastien Cotin
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
| | - François Denis
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
| | - Serge Bouaziz
- Unité de Pharmacologie Chimique & Génétique, Université Paris Descartes, INSERM, CNRS, UFR des Sciences Pharmaceutiques et Biologiques, Paris, France
| | - Sophie Alain
- Centre National de Référence des Cytomégalovirus, Université de Limoges, EA3175, INSERM, Equipe Avenir, Limoges, France
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Champier G, Couvreux A, Hantz S, Rametti A, Mazeron MC, Bouaziz S, Denis F, Alain S. Putative Functional Domains of Human Cytomegalovirus pUL56 Involved in Dimerization and Benzimidazole D-Ribonucleoside Activity. Antivir Ther 2008. [DOI: 10.1177/135965350801300504] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Benzimidazole d-ribonucleosides inhibit DNA packaging during human cytomegalovirus (HCMV) replication. Although they have been shown to target pUL56 and pUL89 (the large and small subunits of the HCMV terminase, respectively) their mechanism of action is not yet fully understood. We aimed here to better understand HCMV DNA maturation and the mechanism of action of benzimidazole derivatives. Methods The HCMV pUL56 protein was studied by sequence analysis of the HCMV UL56 gene and herpesvirus counterparts combined with primary structure analysis of the corresponding amino acid sequences. Results The UL56 sequence analysis of 45 HCMV strains and counterparts among herpesviruses allowed the identification of 12 conserved regions. Moreover, comparison with the product of gene 49 (gp49) of bacteriophage T4 suggested that the pUL56 zinc finger is localized close to the dimerization site of pUL56, providing a spatial organization of the catalytic site that allows recognition and cleavage of DNA. Conclusions This study provides a basis to investigate the mechanism of concatemeric DNA cleavage and a biochemical basis for DNA packaging inhibition by benzimidazole derivatives.
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Affiliation(s)
- Gaël Champier
- Université de Limoges, Faculté de Médecine, Centre Hospitalier Universitaire Dupuytren, EA 3175, Laboratoire de Bactériologie-Virologie-Hygiène, Centre National de Référence Cytomégalovirus, Limoges, France
| | - Anthony Couvreux
- Unité de Pharmacologie Chimique et Génétique; CNRS, UMR 8151, Paris, F-75270 Cedex 06, France
- Inserm, U 640, Paris, F-75270 Cedex 06, France
- Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, F-75270 Cedex 06, France
| | - Sébastien Hantz
- Université de Limoges, Faculté de Médecine, Centre Hospitalier Universitaire Dupuytren, EA 3175, Laboratoire de Bactériologie-Virologie-Hygiène, Centre National de Référence Cytomégalovirus, Limoges, France
| | - Armelle Rametti
- EA 3842 Homéostasie Cellulaire et Pathologie, Faculté de Médecine de Limoges, France
| | - Marie-Christine Mazeron
- Service de Bactériologie-Virologie, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris, Centre National de Référence Cytomegalovirus Associate Laboratory, Paris, France
| | - Serge Bouaziz
- Unité de Pharmacologie Chimique et Génétique; CNRS, UMR 8151, Paris, F-75270 Cedex 06, France
- Inserm, U 640, Paris, F-75270 Cedex 06, France
- Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, Paris, F-75270 Cedex 06, France
| | - François Denis
- Université de Limoges, Faculté de Médecine, Centre Hospitalier Universitaire Dupuytren, EA 3175, Laboratoire de Bactériologie-Virologie-Hygiène, Centre National de Référence Cytomégalovirus, Limoges, France
| | - Sophie Alain
- Université de Limoges, Faculté de Médecine, Centre Hospitalier Universitaire Dupuytren, EA 3175, Laboratoire de Bactériologie-Virologie-Hygiène, Centre National de Référence Cytomégalovirus, Limoges, France
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