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López-Astacio RA, Adu OF, Lee H, Hafenstein SL, Parrish CR. The Structures and Functions of Parvovirus Capsids and Missing Pieces: the Viral DNA and Its Packaging, Asymmetrical Features, Nonprotein Components, and Receptor or Antibody Binding and Interactions. J Virol 2023; 97:e0016123. [PMID: 37367301 PMCID: PMC10373561 DOI: 10.1128/jvi.00161-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Parvoviruses are among the smallest and superficially simplest animal viruses, infecting a broad range of hosts, including humans, and causing some deadly infections. In 1990, the first atomic structure of the canine parvovirus (CPV) capsid revealed a 26-nm-diameter T=1 particle made up of two or three versions of a single protein, and packaging about 5,100 nucleotides of single-stranded DNA. Our structural and functional understanding of parvovirus capsids and their ligands has increased as imaging and molecular techniques have advanced, and capsid structures for most groups within the Parvoviridae family have now been determined. Despite those advances, significant questions remain unanswered about the functioning of those viral capsids and their roles in release, transmission, or cellular infection. In addition, the interactions of capsids with host receptors, antibodies, or other biological components are also still incompletely understood. The parvovirus capsid's apparent simplicity likely conceals important functions carried out by small, transient, or asymmetric structures. Here, we highlight some remaining open questions that may need to be answered to provide a more thorough understanding of how these viruses carry out their various functions. The many different members of the family Parvoviridae share a capsid architecture, and while many functions are likely similar, others may differ in detail. Many of those parvoviruses have not been experimentally examined in detail (or at all in some cases), so we, therefore, focus this minireview on the widely studied protoparvoviruses, as well as the most thoroughly investigated examples of adeno-associated viruses.
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Affiliation(s)
- Robert A. López-Astacio
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Oluwafemi F. Adu
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| | - Hyunwook Lee
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA
| | - Susan L. Hafenstein
- Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, USA
| | - Colin R. Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
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Lakshmanan RV, Hull JA, Berry L, Burg M, Bothner B, McKenna R, Agbandje-McKenna M. Structural Dynamics and Activity of B19V VP1u during the pHs of Cell Entry and Endosomal Trafficking. Viruses 2022; 14:1922. [PMID: 36146728 PMCID: PMC9505059 DOI: 10.3390/v14091922] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/28/2022] [Accepted: 08/28/2022] [Indexed: 12/28/2022] Open
Abstract
Parvovirus B19 (B19V) is a human pathogen that is the causative agent of fifth disease in children. It is also known to cause hydrops in fetuses, anemia in AIDS patients, and transient aplastic crisis in patients with sickle cell disease. The unique N-terminus of Viral Protein 1 (VP1u) of parvoviruses, including B19V, exhibits phospholipase A2 (PLA2) activity, which is required for endosomal escape. Presented is the structural dynamics of B19V VP1u under conditions that mimic the pHs of cell entry and endosomal trafficking to the nucleus. Using circular dichroism spectroscopy, the receptor-binding domain of B19V VP1u is shown to exhibit an α-helical fold, whereas the PLA2 domain exhibits a probable molten globule state, both of which are pH invariant. Differential scanning calorimetry performed at endosomal pHs shows that the melting temperature (Tm) of VP1u PLA2 domain is tuned to body temperature (37 °C) at pH 7.4. In addition, PLA2 assays performed at temperatures ranging from 25-45 °C show both a temperature and pH-dependent change in activity. We hypothesize that VP1u PLA2 domain differences in Tm at differing pHs have enabled the virus to "switch on/off" the phospholipase activity during capsid trafficking. Furthermore, we propose the environment of the early endosome as the optimal condition for endosomal escape leading to B19V infection.
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Affiliation(s)
- Renuk V. Lakshmanan
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Joshua A. Hull
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Luke Berry
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Matthew Burg
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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Wang J, Zhang L. Retrograde Axonal Transport Property of Adeno-Associated Virus and Its Possible Application in Future. Microbes Infect 2021; 23:104829. [PMID: 33878458 DOI: 10.1016/j.micinf.2021.104829] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 03/30/2021] [Accepted: 04/05/2021] [Indexed: 12/19/2022]
Abstract
Gene therapy has become a treatment method for many diseases. Adeno-associated virus (AAV) is one of the most common virus vectors, is also widely used in the gene therapy field. During the past 2 decades, the retrograde axonal transportability of AAV has been discovered and utilized. Many studies have worked on the retrograde axonal transportability of AAV, and more and more people are interested in this field. This review described the current application, influence factors, and mechanism of retrograde axonal transportability of AAV and predicted its potential use in disease treatment in near future.
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Affiliation(s)
- Jingjing Wang
- Department of Gastroenterology, The Third Central Hospital of Tianjin, 83 Jintang Road, Hedong District, Tianjin, 300170, China
| | - Liqin Zhang
- Department of Otolaryngology, Peking Union Medical College Hospital, Dongcheng Qu, Beijing, 100730, China.
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Du J, Wang W, Chan JFW, Wang G, Huang Y, Yi Y, Zhu Z, Peng R, Hu X, Wu Y, Zeng J, Zheng J, Cui X, Niu L, Zhao W, Lu G, Yuen KY, Yin F. Identification of a Novel Ichthyic Parvovirus in Marine Species in Hainan Island, China. Front Microbiol 2019; 10:2815. [PMID: 31866980 PMCID: PMC6907010 DOI: 10.3389/fmicb.2019.02815] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/20/2019] [Indexed: 01/27/2023] Open
Abstract
Parvoviruses are a diverse group of viruses that are capable of infecting a wide range of animals. In this study, we report the discovery of a novel parvovirus, tilapia parvovirus HMU-HKU, in the fecal samples of crocodiles and intestines of tilapia in Hainan Province, China. The novel parvovirus was firstly identified from crocodiles fed with tilapia using next-generation sequencing (NGS). Screening studies revealed that the prevalence of the novel parvovirus in crocodile feces samples fed on tilapia (75–86%) was apparently higher than that in crocodiles fed with chicken (4%). Further studies revealed that the prevalence of the novel parvovirus in tilapia feces samples collected at four areas in Hainan Province was between 40 and 90%. Four stains of the novel parvovirus were identified in this study based on sequence analyses of NS1 and all the four strains were found in tilapia in contrast only two of them were detected in crocodile feces. The nearly full-length genome sequence of the tilapia parvovirus HMU-HKU-1 was determined and showed less than 45.50 and 40.38% amino acid identity with other members of Parvoviridae in NS1 and VP1 genes, respectively. Phylogenetic analysis based on the complete helicase domain amino acid sequences showed that the tilapia parvovirus HMU-HKU-1 formed a relatively independent branch in the newly proposed genus Chaphamaparvovirus in the subfamily Hamaparvovirinae according to the ICTV’s most recent taxonomic criteria for Parvoviridae classification. Tilapia parvovirus HMU-HKU-1 likely represented a new species within the new genus Chaphamaparvovirus. The identification of tilapia parvovirus HMU-HKU provides further insight into the viral and genetic diversity of parvoviruses and its infections in tilapia populations need to be evaluated in terms of pathogenicity and production losses in tilapia farming.
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Affiliation(s)
- Jiang Du
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Wenqi Wang
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Jasper Fuk-Woo Chan
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong.,Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Pokfulam, Hong Kong
| | - Gaoyu Wang
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Yi Huang
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Yufang Yi
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Zheng Zhu
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong.,Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Pokfulam, Hong Kong
| | - Ruoyan Peng
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Xiaoyuan Hu
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Yue Wu
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China
| | - Jifeng Zeng
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province, Hainan University, Haikou, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Haikou, China
| | - Jiping Zheng
- Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Hainan University, Haikou, China
| | - Xiuji Cui
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Lina Niu
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Wei Zhao
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Gang Lu
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
| | - Kwok-Yung Yuen
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Pokfulam, Hong Kong.,Department of Microbiology, The University of Hong Kong, Pokfulam, Hong Kong.,Carol Yu Centre for Infection, The University of Hong Kong, Pokfulam, Hong Kong
| | - Feifei Yin
- Hainan Medical University-The University of Hong Kong Joint Laboratory of Tropical Infectious Diseases, Hainan Medical University, Haikou, China.,Key Laboratory of Tropical Translational Medicine of Ministry of Education, Hainan Medical University, Haikou, China.,Department of Pathogen Biology, Hainan Medical University, Haikou, China
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Maurya S, Mary B, Jayandharan GR. Rational Engineering and Preclinical Evaluation of Neddylation and SUMOylation Site Modified Adeno-Associated Virus Vectors in Murine Models of Hemophilia B and Leber Congenital Amaurosis. Hum Gene Ther 2019; 30:1461-1476. [PMID: 31642343 PMCID: PMC6919284 DOI: 10.1089/hum.2019.164] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Synthetic engineering of viral vectors such as adeno-associated virus (AAV) is crucial to overcome host transduction barriers observed during clinical gene therapy. We reasoned that exploring the role of cellular ubiquitin-like modifiers (UBLs) such as Neddylation or SUMOylation during AAV transduction could be beneficial. Using a combination of in silico biochemical and molecular engineering strategies, we have studied the impact of these UBLs during AAV2 infection and further developed Neddylation or SUMOylation site–modified AAV vectors and validated them in multiple disease models in vitro and in vivo. Hepatic gene transfer of two novel vectors developed, K105Q (SUMOylation-site mutant) and K665Q (Neddylation-site mutant), demonstrated a significantly improved human coagulation factor (F) IX expression (up to two-fold) in a murine model of hemophilia B. Furthermore, subretinal gene transfer of AAV2-K105Q vector expressing RPE65 gene demonstrated visual correction in a murine model of a retinal degenerative disease (rd12 mice). These vectors did not have any adverse immunogenic events in vivo. Taken together, we demonstrate that gene delivery vectors specifically engineered at UBLs can improve the therapeutic outcome during AAV-mediated ocular or hepatic gene therapy.
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Affiliation(s)
- Shubham Maurya
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, Uttar Pradesh, India
| | - Bertin Mary
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, Uttar Pradesh, India
| | - Giridhara R Jayandharan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, Uttar Pradesh, India
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Wang B, Wang XL. Species diversity of fecal microbial flora in Canis lupus familiaris infected with canine parvovirus. Vet Microbiol 2019; 237:108390. [PMID: 31585652 DOI: 10.1016/j.vetmic.2019.108390] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 08/13/2019] [Accepted: 08/15/2019] [Indexed: 02/02/2023]
Abstract
Parvovirosis is a highly contagious disease in dogs, often causing acute hemorrhagic enteritis and altering the intestinal microflora. In this study, real-time PCR was used to detect the viral copy numbers in dogs diagnosed with the disease. Hematological and hemobiochemical parameters were also determined. The species and abundances of the fecal microbial flora in both sick and healthy dogs were determined and compared via metagenomic sequencing. The viral copy numbers in the sick dogs were infected with little difference in the positive samples. The blood coagulation time was significantly shorter and the number of white blood cells was significantly greater in the sick dogs. The serum calcium content was slightly increased and the phosphorus content was reduced in the sick dogs. The LDH and CK activities were significantly elevated in the sick dogs. Metagenomic sequencing and analysis revealed relatively more Escherichia, Lachnoclostridium, gnavus group (Ruminococcus), and uncultured_bacterium_f_lachnospiraceae in the infected dogs, whereas the abundance of Collinsella was relatively reduced. Alloprevotella and Sutterella were absent among the fecal microorganisms of the infected dogs. The relative abundances of Romboutsia, Erysipelatoclostridium, Anaerotruncus, and Blautia were significantly increased in the infected dogs. Functional analysis of the metagenomes of the samples indicated a significant enrichment of the 'replication, recombination and repair', 'nucleotide transport and metabolism', 'transcription', and 'defense metabolism' functions in the fecal microbial flora of the infected dogs. In summary, this study provides a scientific theoretical basis for preventing and controlling diarrhea caused by the canine parvovirus.
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Affiliation(s)
- Bi Wang
- College of Wildlife and Protected Area, Northeast Forestry University, PR China; Center of Conservation Medicine and Ecological Safety, Northeast Forestry University, PR China.
| | - Xiao-Long Wang
- College of Wildlife and Protected Area, Northeast Forestry University, PR China; Center of Conservation Medicine and Ecological Safety, Northeast Forestry University, PR China.
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Complex and Dynamic Interactions between Parvovirus Capsids, Transferrin Receptors, and Antibodies Control Cell Infection and Host Range. J Virol 2018; 92:JVI.00460-18. [PMID: 29695427 DOI: 10.1128/jvi.00460-18] [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: 03/19/2018] [Accepted: 04/17/2018] [Indexed: 01/18/2023] Open
Abstract
Antibody and receptor binding are key virus-host interactions that control host range and determine the success of infection. Canine and feline parvovirus capsids bind the transferrin receptor type 1 (TfR) to enter host cells, and specific structural interactions appear necessary to prepare the stable capsids for infection. Here, we define the details of binding, competition, and occupancy of wild-type and mutant parvovirus capsids with purified receptors and antibodies. TfR-capsid binding interactions depended on the TfR species and varied widely, with no direct relationship between binding affinity and infection. Capsids bound feline, raccoon, and black-backed jackal TfRs at high affinity but barely bound canine TfRs, which mediated infection efficiently. TfRs from different species also occupied capsids to different levels, with an estimated 1 to 2 feline TfRs but 12 black-backed jackal TfRs binding each capsid. Multiple alanine substitutions within loop 1 on the capsid surface reduced TfR binding but substitutions within loop 3 did not, suggesting that loop 1 directly engaged the TfR and loop 3 sterically affected that interaction. Binding and competition between different TfRs and/or antibodies showed complex relationships. Both antibodies 14 and E competed capsids off TfRs, but antibody E could also compete capsids off itself and antibody 14, likely by inducing capsid structural changes. In some cases, the initial TfR or antibody binding event affected subsequent TfR binding, suggesting that capsid structure changes occur after TfR or antibody binding and may impact infection. This shows that precise, host-specific TfR-capsid interactions, beyond simple attachment, are important for successful infection.IMPORTANCE Host receptor binding is a key step during viral infection and may control both infection and host range. In addition to binding, some viruses require specific interactions with host receptors in order to infect, and anti-capsid antibodies can potentially disrupt these interactions, leading to neutralization. Here, we examine the interactions between parvovirus capsids, the receptors from different hosts, and anti-capsid antibodies. We show that interactions between parvovirus capsids and host-specific TfRs vary in both affinity and in the numbers of receptors bound, with complex effects on infection. In addition, antibodies binding to two sites on the capsids had different effects on TfR-capsid binding. These experiments confirm that receptor and antibody binding to parvovirus capsids are complex processes, and the infection outcome is not determined simply by the affinity of attachment.
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Viral highway to nucleus exposed by image correlation analyses. Sci Rep 2018; 8:1152. [PMID: 29348472 PMCID: PMC5773500 DOI: 10.1038/s41598-018-19582-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 01/04/2018] [Indexed: 01/26/2023] Open
Abstract
Parvoviral genome translocation from the plasma membrane into the nucleus is a coordinated multistep process mediated by capsid proteins. We used fast confocal microscopy line scan imaging combined with image correlation methods including auto-, pair- and cross-correlation, and number and brightness analysis, to study the parvovirus entry pathway at the single-particle level in living cells. Our results show that the endosome-associated movement of virus particles fluctuates from fast to slow. Fast transit of single cytoplasmic capsids to the nuclear envelope is followed by slow movement of capsids and fast diffusion of capsid fragments in the nucleoplasm. The unique combination of image analyses allowed us to follow the fate of intracellular single virus particles and their interactions with importin β revealing previously unknown dynamics of the entry pathway.
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Protoparvovirus Knocking at the Nuclear Door. Viruses 2017; 9:v9100286. [PMID: 28974036 PMCID: PMC5691637 DOI: 10.3390/v9100286] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 12/20/2022] Open
Abstract
Protoparvoviruses target the nucleus due to their dependence on the cellular reproduction machinery during the replication and expression of their single-stranded DNA genome. In recent years, our understanding of the multistep process of the capsid nuclear import has improved, and led to the discovery of unique viral nuclear entry strategies. Preceded by endosomal transport, endosomal escape and microtubule-mediated movement to the vicinity of the nuclear envelope, the protoparvoviruses interact with the nuclear pore complexes. The capsids are transported actively across the nuclear pore complexes using nuclear import receptors. The nuclear import is sometimes accompanied by structural changes in the nuclear envelope, and is completed by intranuclear disassembly of capsids and chromatinization of the viral genome. This review discusses the nuclear import strategies of protoparvoviruses and describes its dynamics comprising active and passive movement, and directed and diffusive motion of capsids in the molecularly crowded environment of the cell.
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Pillay S, Carette JE. Host determinants of adeno-associated viral vector entry. Curr Opin Virol 2017; 24:124-131. [PMID: 28672171 DOI: 10.1016/j.coviro.2017.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 05/28/2017] [Accepted: 06/09/2017] [Indexed: 12/18/2022]
Abstract
Viral vectors based on adeno-associated virus (AAV) are leading candidates for therapeutic gene delivery. Understanding rate-limiting steps in the entry of AAV vectors may be used in a rational approach to improve efficiency and specificity of transduction. This review describes our current understanding of AAV entry, a key step during infection. We discuss the identity and functions of AAV receptors and attachment factors, including the recently discovered multi-serotype receptor AAVR. We further provide an overview of other host factors that act during the trafficking stage of AAV vector transduction. In particular, we focus on cellular protein complexes associated with retrograde transport from endosomes to the trans-Golgi network. The novel insights in AAV-host interactions facilitated by technological advances in genetic screening approaches provide a greater depth in our understanding how AAV vectors exploit host factors to deliver its genetic cargo to the nucleus.
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Affiliation(s)
- Sirika Pillay
- Stanford University, Department of Microbiology and Immunology, Stanford, CA 94305, USA
| | - Jan E Carette
- Stanford University, Department of Microbiology and Immunology, Stanford, CA 94305, USA.
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Saito M, Otsu W, Hsu KS, Chuang JZ, Yanagisawa T, Shieh V, Kaitsuka T, Wei FY, Tomizawa K, Sung CH. Tctex-1 controls ciliary resorption by regulating branched actin polymerization and endocytosis. EMBO Rep 2017; 18:1460-1472. [PMID: 28607034 DOI: 10.15252/embr.201744204] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/13/2017] [Accepted: 05/16/2017] [Indexed: 11/09/2022] Open
Abstract
The primary cilium is a plasma membrane-protruding sensory organelle that undergoes regulated assembly and resorption. While the assembly process has been studied extensively, the cellular machinery that governs ciliary resorption is less well understood. Previous studies showed that the ciliary pocket membrane is an actin-rich, endocytosis-active periciliary subdomain. Furthermore, Tctex-1, originally identified as a cytoplasmic dynein light chain, has a dynein-independent role in ciliary resorption upon phosphorylation at Thr94. Here, we show that the remodeling and endocytosis of the ciliary pocket membrane are accelerated during ciliary resorption. This process depends on phospho(T94)Tctex-1, actin, and dynamin. Mechanistically, Tctex-1 physically and functionally interacts with the actin dynamics regulators annexin A2, Arp2/3 complex, and Cdc42. Phospho(T94)Tctex-1 is required for Cdc42 activation before the onset of ciliary resorption. Moreover, inhibiting clathrin-dependent endocytosis or suppressing Rab5GTPase on early endosomes effectively abrogates ciliary resorption. Taken together with the epistasis functional assays, our results support a model in which phospho(T94)Tctex-1-regulated actin polymerization and periciliary endocytosis play an active role in orchestrating the initial phase of ciliary resorption.
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Affiliation(s)
- Masaki Saito
- Department of Molecular Pharmacology, Graduate School of Medicine, Tohoku University, Aoba-ku Sendai, Japan .,Department of Cellular Signaling, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba-ku Sendai, Japan.,Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Wataru Otsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Kuo-Shun Hsu
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Jen-Zen Chuang
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Teruyuki Yanagisawa
- Department of Molecular Pharmacology, Graduate School of Medicine, Tohoku University, Aoba-ku Sendai, Japan
| | - Vincent Shieh
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA
| | - Taku Kaitsuka
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Ching-Hwa Sung
- Department of Ophthalmology, Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY, USA .,Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, NY, USA
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12
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Parvovirus Capsid Structures Required for Infection: Mutations Controlling Receptor Recognition and Protease Cleavages. J Virol 2017; 91:JVI.01871-16. [PMID: 27847360 DOI: 10.1128/jvi.01871-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/01/2016] [Indexed: 01/11/2023] Open
Abstract
Parvovirus capsids are small but complex molecular machines responsible for undertaking many of the steps of cell infection, genome packing, and cell-to-cell as well as host-to-host transfer. The details of parvovirus infection of cells are still not fully understood, but the processes must involve small changes in the capsid structure that allow the endocytosed virus to escape from the endosome, pass through the cell cytoplasm, and deliver the single-stranded DNA (ssDNA) genome to the nucleus, where viral replication occurs. Here, we examine capsid substitutions that eliminate canine parvovirus (CPV) infectivity and identify how those mutations changed the capsid structure or altered interactions with the infectious pathway. Amino acid substitutions on the exterior surface of the capsid (Gly299Lys/Ala300Lys) altered the binding of the capsid to transferrin receptor type 1 (TfR), particularly during virus dissociation from the receptor, but still allowed efficient entry into both feline and canine cells without successful infection. These substitutions likely control specific capsid structural changes resulting from TfR binding required for infection. A second set of changes on the interior surface of the capsid reduced viral infectivity by >100-fold and included two cysteine residues and neighboring residues. One of these substitutions, Cys270Ser, modulates a VP2 cleavage event found in ∼10% of the capsid proteins that also was shown to alter capsid stability. A neighboring substitution, Pro272Lys, significantly reduced capsid assembly, while a Cys273Ser change appeared to alter capsid transport from the nucleus. These mutants reveal additional structural details that explain cell infection processes of parvovirus capsids. IMPORTANCE Parvoviruses are commonly found in both vertebrate and invertebrate animals and cause widespread disease. They are also being developed as oncolytic therapeutics and as gene therapy vectors. Most functions involved in infection or transduction are mediated by the viral capsid, but the structure-function correlates of the capsids and their constituent proteins are still incompletely understood, especially in relation to identifying capsid processes responsible for infection and release from the cell. Here, we characterize the functional effects of capsid protein mutations that result in the loss of virus infectivity, giving a better understanding of the portions of the capsid that mediate essential steps in successful infection pathways and how they contribute to viral infectivity.
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13
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Cellular transduction mechanisms of adeno-associated viral vectors. Curr Opin Virol 2016; 21:54-60. [PMID: 27544821 DOI: 10.1016/j.coviro.2016.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 07/30/2016] [Accepted: 08/01/2016] [Indexed: 12/27/2022]
Abstract
Recombinant adeno-associated viral vectors (rAAV) are regarded as promising vehicles for therapeutic gene delivery. Continued development and new strategies are essential to improve the potency of AAV vectors and reduce the effective dose needed for clinical efficacy. In this regard, many studies have focused on understanding the cellular transduction mechanisms of rAAV, often with the goal of exploiting this knowledge to increase gene transfer efficiency. Here, we provide an overview of our evolving understanding of rAAV cellular trafficking pathways through the host cell, beginning with cellular entry and ending with transcription of the vector genome. Strategies to exploit this information for improving rAAV transduction are discussed.
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14
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ICAM-1 Binding Rhinoviruses A89 and B14 Uncoat in Different Endosomal Compartments. J Virol 2016; 90:7934-42. [PMID: 27334586 DOI: 10.1128/jvi.00712-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/20/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Human rhinovirus A89 (HRV-A89) and HRV-B14 bind to and are internalized by intercellular adhesion molecule 1 (ICAM-1); as demonstrated earlier, the RNA genome of HRV-B14 penetrates into the cytoplasm from endosomal compartments of the lysosomal pathway. Here, we show by immunofluorescence microscopy that HRV-A89 but not HRV-B14 colocalizes with transferrin in the endocytic recycling compartment (ERC). Applying drugs differentially interfering with endosomal recycling and with the pathway to lysosomes, we demonstrate that these two major-group HRVs productively uncoat in distinct endosomal compartments. Overexpression of constitutively active (Rab11-GTP) and dominant negative (Rab11-GDP) mutants revealed that uncoating of HRV-A89 depends on functional Rab11. Thus, two ICAM-1 binding HRVs are routed into distinct endosomal compartments for productive uncoating. IMPORTANCE Based on similarity of their RNA genomic sequences, the more than 150 currently known common cold virus serotypes were classified as species A, B, and C. The majority of HRV-A viruses and all HRV-B viruses use ICAM-1 for cell attachment and entry. Our results highlight important differences of two ICAM-1 binding HRVs with respect to their intracellular trafficking and productive uncoating; they demonstrate that serotypes belonging to species A and B, but entering the cell via the same receptors, direct the endocytosis machinery to ferry them along distinct pathways toward different endocytic compartments for uncoating.
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15
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Abdelhakim AH, Salgado EN, Fu X, Pasham M, Nicastro D, Kirchhausen T, Harrison SC. Structural correlates of rotavirus cell entry. PLoS Pathog 2014; 10:e1004355. [PMID: 25211455 PMCID: PMC4161437 DOI: 10.1371/journal.ppat.1004355] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 07/24/2014] [Indexed: 01/06/2023] Open
Abstract
Cell entry by non-enveloped viruses requires translocation into the cytosol of a macromolecular complex--for double-strand RNA viruses, a complete subviral particle. We have used live-cell fluorescence imaging to follow rotavirus entry and penetration into the cytosol of its ∼ 700 Å inner capsid particle ("double-layered particle", DLP). We label with distinct fluorescent tags the DLP and each of the two outer-layer proteins and track the fates of each species as the particles bind and enter BSC-1 cells. Virions attach to their glycolipid receptors in the host cell membrane and rapidly become inaccessible to externally added agents; most particles that release their DLP into the cytosol have done so by ∼ 10 minutes, as detected by rapid diffusional motion of the DLP away from residual outer-layer proteins. Electron microscopy shows images of particles at various stages of engulfment into tightly fitting membrane invaginations, consistent with the interpretation that rotavirus particles drive their own uptake. Electron cryotomography of membrane-bound virions also shows closely wrapped membrane. Combined with high resolution structural information about the viral components, these observations suggest a molecular model for membrane disruption and DLP penetration.
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Affiliation(s)
- Aliaa H. Abdelhakim
- Laboratory of Molecular Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Eric N. Salgado
- Laboratory of Molecular Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xiaofeng Fu
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Mithun Pasham
- Program in Cellular and Molecular Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Daniela Nicastro
- Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts, United States of America
| | - Tomas Kirchhausen
- Program in Cellular and Molecular Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Stephen C. Harrison
- Laboratory of Molecular Medicine, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- * E-mail:
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16
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Garcin PO, Panté N. Cell migration is another player of the minute virus of mice infection. Virology 2014; 468-470:150-159. [PMID: 25173091 DOI: 10.1016/j.virol.2014.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 07/21/2014] [Accepted: 08/01/2014] [Indexed: 11/28/2022]
Abstract
The parvovirus minute virus of mice, prototype strain (MVMp), preferentially infects and kills cancer cells. This intrinsic MVMp oncotropism may depend in part on the early stages of MVMp infection. To test this hypothesis, we investigated the early events of MVMp infection in mouse LA9 fibroblasts and a highly invasive mouse mammary tumor cell line derived from polyomavirus middle T antigen-mediated transformation. Using a combination of fluorescence and electron microscopy, we found that various parameters of the cell migration process affect MVMp infection. We show that, after binding to the plasma membrane, MVMp particles rapidly cluster at the leading edge of migrating cells, which exhibit higher levels of MVMp uptake than non-motile cells. Moreover, promoting cell migration on a fibronectin matrix increased MVMp infection, and induction of epithelial-mesenchymal transition allowed MVMp replication in non-permissive epithelial cells. Hence, we propose that cell migration influences the early stages of MVMp infection.
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Affiliation(s)
- Pierre O Garcin
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
| | - Nelly Panté
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4.
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17
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Lyi SM, Tan MJA, Parrish CR. Parvovirus particles and movement in the cellular cytoplasm and effects of the cytoskeleton. Virology 2014; 456-457:342-52. [PMID: 24889253 DOI: 10.1016/j.virol.2014.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 04/03/2014] [Accepted: 04/03/2014] [Indexed: 12/20/2022]
Abstract
Cell infection by parvoviruses requires that capsids be delivered from outside the cell to the cytoplasm, followed by genome trafficking to the nucleus. Here we microinject capsids into cells that lack receptors and followed their movements within the cell over time. In general the capsids remained close to the positions where they were injected, and most particles did not move to the vicinity of or enter the nucleus. When 70 kDa-dextran was injected along with the capsids that did not enter the nucleus in significant amounts. Capsids conjugated to peptides containing the SV40 large T-antigen nuclear localization signal remained in the cytoplasm, although bovine serum albumen conjugated to the same peptide entered the nucleus rapidly. No effects of disruption of microfilaments, intermediate filaments, or microtubules on the distribution of the capsids were observed. These results suggest that movement of intact capsids within cells is primarily associated with passive processes.
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Affiliation(s)
- Sangbom Michael Lyi
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
| | - Min Jie Alvin Tan
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States.
| | - Colin R Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States.
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18
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Abstract
The cell signaling plays a pivotal role in regulating cellular processes and is often manipulated by viruses as they rely on the functions offered by cells for their propagation. The first stage of their host life is to pass the genetic materials into the cell. Although some viruses can directly penetrate into cytosol, in fact, most virus entry into their host cells is through endocytosis. This machinery initiates with cell type specific cellular signaling pathways, and the signaling compounds can be proteins, lipids, and carbohydrates. The activation can be triggered in a very short time after virus binds on target cells, such as receptors. The signaling pathways involved in regulation of viral entry are wide diversity that often cross-talk between different endocytosis results. Furthermore, some viruses have the ability to use the multiple internalization pathways which leads to the regulation being even more complex. In this paper, we discuss some recent advances in our understanding of cellular pathways for virus entry, molecular signaling during virus entry, formation of endocytic vesicles, and the traffic.
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Affiliation(s)
- Pei-I Chi
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan
| | - Hung-Jen Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan
- Agricultural Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
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19
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Echovirus 7 entry into polarized caco-2 intestinal epithelial cells involves core components of the autophagy machinery. J Virol 2013; 88:434-43. [PMID: 24155402 DOI: 10.1128/jvi.02706-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Echovirus 7 enters polarized Caco-2 intestinal epithelial cells by a clathrin-mediated endocytic process and then moves through the endosomal system before releasing its genome into the cytoplasm. We examined the possible role in virus entry of core components of the autophagy machinery. We found that depletion of Beclin-1, Atg12, Atg14, Atg16, or LC3 with specific small interfering RNAs inhibited echovirus 7 infection upstream of uncoating but had little or no effect on virus attachment to the cell surface. These data indicate that multiple autophagy-related proteins are important for one or more events that occur after the virus has bound its receptor on the cell surface but before RNA is released from the virus capsid. Although we have not determined the mechanism by which each protein contributes to virus entry, we found that stable depletion of Atg16L1 interfered with virus internalization from the cell surface rather than with intracellular trafficking. Autophagy gene products may thus participate in the endocytic process that moves virus into polarized Caco-2 cells.
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20
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Harman AN, Kim M, Nasr N, Sandgren KJ, Cameron PU. Tissue dendritic cells as portals for HIV entry. Rev Med Virol 2013; 23:319-33. [PMID: 23908074 DOI: 10.1002/rmv.1753] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 12/24/2022]
Abstract
Dendritic cells (DCs) are found at the portals of pathogen entry such as the mucosal surfaces of the respiratory, gastrointestinal and genital tracts where they represent the first line of contact between the immune system and the foreign invaders. They are found throughout the body in multiple subsets where they express unique combinations of C-type lectin receptors to best aid them in detection of pathogens associated with their anatomical location. DCs are important in the establishment in HIV infection for two reasons. Firstly, they are one of the first cells to encounter the virus, and the specific interaction that occurs between these cells and HIV is critical to HIV establishing a foothold infection. Secondly and most importantly, HIV is able to efficiently transfer the virus to its primary target cell, the CD4(+) T lymphocyte, in which it replicates explosively. Infection of CD4(+) T lymphocytes via DCs is far more efficient than direct infection. This review surveys the various DCs subsets found within the human sexual mucosa and their interactions with HIV. Mechanisms of HIV uptake are discussed as well as how the virus then traffics through the DC and is transferred to T cells. Until recently, most research has focussed on vaginal transmission despite the increased transmission rate associated with anal intercourse. Here, we also discuss recent advances in our understanding of HIV transmission in the colon.
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21
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Fay N, Panté N. The intermediate filament network protein, vimentin, is required for parvoviral infection. Virology 2013; 444:181-90. [PMID: 23838001 DOI: 10.1016/j.virol.2013.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 03/21/2013] [Accepted: 06/07/2013] [Indexed: 12/27/2022]
Abstract
Intermediate filaments (IFs) have recently been shown to serve novel roles during infection by many viruses. Here we have begun to study the role of IFs during the early steps of infection by the parvovirus minute virus of mice (MVM). We found that during early infection with MVM, after endosomal escape, the vimentin IF network was considerably altered, yielding collapsed immunofluorescence staining near the nuclear periphery. Furthermore, we found that vimentin plays an important role in the life cycle of MVM. The number of cells, which successfully replicated MVM, was reduced in infected cells in which the vimentin network was genetically or pharmacologically modified; viral endocytosis, however, remained unaltered. Perinuclear accumulation of MVM-containing vesicles was reduced in cells lacking vimentin. Our data suggests that vimentin is required for the MVM life cycle, presenting possibly a dual role: (1) following MVM escape from endosomes and (2) during endosomal trafficking of MVM.
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Affiliation(s)
- Nikta Fay
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia, Canada V6T 1Z4
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22
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Cunningham AL, Harman A, Kim M, Nasr N, Lai J. Immunobiology of dendritic cells and the influence of HIV infection. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 762:1-44. [PMID: 22975870 DOI: 10.1007/978-1-4614-4433-6_1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent progress in phenotyping of human dendritic cells (DCs) has allowed a closer alignment of the classification and functions of murine and human dendritic cell subsets. Marked differences in the functions of these human DC subsets and their response to HIV infection have become apparent, relevant to HIV pathogenesis and vaccine and microbicide development. Systems biology approaches to studying HIV uptake and infection of dendritic cells has revealed how markedly HIV subverts their functions, especially in relation to the trafficking pathways and viral transfer to T cells. Furthermore the interactions between DCs and other innate immune cells, NK cells, NKT cells and gamma delta T cells are now known to influence DC and T cell function and are also disturbed by HIV infection in vitro and in vivo. Such cellular interactions are potential targets for vaccine adjuvants and immunotherapy.
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23
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Endosomal maturation, Rab7 GTPase and phosphoinositides in African swine fever virus entry. PLoS One 2012; 7:e48853. [PMID: 23133661 PMCID: PMC3486801 DOI: 10.1371/journal.pone.0048853] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2012] [Accepted: 10/02/2012] [Indexed: 11/22/2022] Open
Abstract
Here we analyzed the dependence of African swine fever virus (ASFV) infection on the integrity of the endosomal pathway. Using confocal immunofluorescence with antibodies against viral capsid proteins, we found colocalization of incoming viral particles with early endosomes (EE) during the first minutes of infection. Conversely, viral capsid protein was not detected in acidic late endosomal compartments, multivesicular bodies (MVBs), late endosomes (LEs) or lysosomes (LY). Using an antibody against a viral inner core protein, we found colocalization of viral cores with late compartments from 30 to 60 minutes postinfection. The absence of capsid protein staining in LEs and LYs suggested that virus desencapsidation would take place at the acid pH of these organelles. In fact, inhibitors of intraluminal acidification of endosomes caused retention of viral capsid staining virions in Rab7 expressing endosomes and more importantly, severely impaired subsequent viral protein production. Endosomal acidification in the first hour after virus entry was essential for successful infection but not thereafter. In addition, altering the balance of phosphoinositides (PIs) which are responsible of the maintenance of the endocytic pathway impaired ASFV infection. Early infection steps were dependent on the production of phosphatidylinositol 3-phosphate (PtdIns3P) which is involved in EE maturation and multivesicular body (MVB) biogenesis and on the interconversion of PtdIns3P to phosphatidylinositol 3, 5-biphosphate (PtdIns(3,5)P2). Likewise, GTPase Rab7 activity should remain intact, as well as processes related to LE compartment physiology, which are crucial during early infection. Our data demonstrate that the EE and LE compartments and the integrity of the endosomal maturation pathway orchestrated by Rab proteins and PIs play a central role during early stages of ASFV infection.
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24
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Abstract
Parvoviruses package a ssDNA genome. Both nonpathogenic and pathogenic members exist, including those that cause fetal infections, encompassing the entire spectrum of virus phenotypes. Their small genomes and simple coding strategy has enabled functional annotation of many steps in the infectious life cycle. They assemble a multifunctional capsid responsible for cell recognition and the transport of the packaged genome to the nucleus for replication and progeny virus production. It is also the target of the host immune response. Understanding how the capsid structure relates to the function of parvoviruses provides a platform for recombinant engineering of viral gene delivery vectors for the treatment of clinical diseases, and is fundamental for dissecting the viral determinants of pathogenicity. This review focuses on our current understanding of parvovirus capsid structure and function with respect to the infectious life cycle.
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Affiliation(s)
- Sujata Halder
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
| | - Robert Ng
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry & Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, College of Medicine, 1600 SW Archer Road, PO Box 100245, University of Florida, Gainesville, FL 32610, USA
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25
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Limited transferrin receptor clustering allows rapid diffusion of canine parvovirus into clathrin endocytic structures. J Virol 2012; 86:5330-40. [PMID: 22357278 DOI: 10.1128/jvi.07194-11] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral pathogens usurp cell surface receptors to access clathrin endocytic structures, yet the mechanisms of virus incorporation into these structures remain incompletely understood. Here we used fluorescence microscopy to directly visualize the association of single canine parvovirus (CPV) capsids with cellular transferrin receptors (TfR) on the surfaces of live feline cells and to monitor how these CPV-TfR complexes access endocytic structures. We found that most capsids associated with fewer than five TfRs and that ∼25% of TfR-bound capsids laterally diffused into assembling clathrin-coated pits less than 30 s after attachment. Capsids that did not encounter a coated pit dissociated from the cell surface with a half-life of ∼30 s. Together, our results show how CPV exploits the natural mechanism of TfR endocytosis to engage the clathrin endocytic pathway and reveal that the low affinity of capsids for feline TfRs limits the residence time of capsids on the cell surface and thus the efficiency of virus internalization.
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26
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Rhesus rotavirus trafficking during entry into MA104 cells is restricted to the early endosome compartment. J Virol 2012; 86:4009-13. [PMID: 22278225 DOI: 10.1128/jvi.06667-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Endocytosis has recently been implicated in rotavirus (RV) entry. We examined the role of Rabs, which regulate endosomal trafficking, during RV entry. Several structural proteins of neuraminidase-sensitive and -insensitive RVs colocalized with Rab5, an early endosome marker, but not Rab7, a late endosome marker. Dominant-negative and constitutively active mutants demonstrated that Rab5 but not Rab4 or Rab7 affects rhesus RV (RRV) infectivity. These data suggest that early RRV trafficking is confined to the early endosome compartment and requires Rab5.
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27
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Harbison CE, Weichert WS, Gurda BL, Chiorini JA, Agbandje-McKenna M, Parrish CR. Examining the cross-reactivity and neutralization mechanisms of a panel of mAbs against adeno-associated virus serotypes 1 and 5. J Gen Virol 2011; 93:347-355. [PMID: 22071509 DOI: 10.1099/vir.0.035113-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Neutralizing antibodies play a central role in the prevention and clearance of viral infections, but can be detrimental to the use of viral capsids for gene delivery. Antibodies present a major hurdle for ongoing clinical trials using adeno-associated viruses (AAVs); however, relatively little is known about the antigenic epitopes of most AAV serotypes or the mechanism(s) of antibody-mediated neutralization. We developed panels of AAV mAbs by repeatedly immunizing mice with AAV serotype 1 (AAV1) capsids, or by sequentially immunizing with AAV1 followed by AAV5 capsids, in order to examine the efficiency and mechanisms of antibody-mediated neutralization. The antibodies were not cross-reactive between heterologous AAV serotypes except for a low level of recognition of AAV1 capsids by the AAV5 antibodies, probably due to the initial immunization with AAV1. The neutralization efficiency of different IgGs varied and Fab fragments derived from these antibodies were generally poorly neutralizing. The antibodies appeared to display various alternative mechanisms of neutralization, which included inhibition of receptor-binding and interference with a post-attachment step.
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Affiliation(s)
- Carole E Harbison
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Wendy S Weichert
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Brittney L Gurda
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - John A Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, US National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
| | - Colin R Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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28
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Caillet M, Janvier K, Pelchen–Matthews A, Delcroix-Genête D, Camus G, Marsh M, Berlioz-Torrent C. Rab7A is required for efficient production of infectious HIV-1. PLoS Pathog 2011; 7:e1002347. [PMID: 22072966 PMCID: PMC3207927 DOI: 10.1371/journal.ppat.1002347] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 09/16/2011] [Indexed: 01/24/2023] Open
Abstract
Retroviruses take advantage of cellular trafficking machineries to assemble and release new infectious particles. Rab proteins regulate specific steps in intracellular membrane trafficking by recruiting tethering, docking and fusion factors, as well as the actin- and microtubule-based motor proteins that facilitate vesicle traffic. Using virological tests and RNA interference targeting Rab proteins, we demonstrate that the late endosome-associated Rab7A is required for HIV-1 propagation. Analysis of the late steps of the HIV infection cycle shows that Rab7A regulates Env processing, the incorporation of mature Env glycoproteins into viral particles and HIV-1 infectivity. We also show that siRNA-mediated Rab7A depletion induces a BST2/Tetherin phenotype on HIV-1 release. BST2/Tetherin is a restriction factor that impedes HIV-1 release by tethering mature virus particles to the plasma membrane. Our results suggest that Rab7A contributes to the mechanism by which Vpu counteracts the restriction factor BST2/Tetherin and rescues HIV-1 release. Altogether, our results highlight new roles for a major regulator of the late endocytic pathway, Rab7A, in the late stages of the HIV-1 replication cycle. Human immunodeficiency virus (HIV) propagation requires the assistance of host cell factors at all stages of the infection cycle. HIV exploits components of the cellular membrane sorting machinery for its assembly, budding and release. Rab GTPases are key regulators of membrane-trafficking events, including exocytosis and endocytosis, in eukaryotic cells. Here we show that the late endosome associated Rab7A plays a major role in HIV-1 replication. We find that Rab7A regulates the production of infectious HIV-1 particles at two critical stages. First, Rab7A is required for efficient Env processing and, thus, for the incorporation of mature HIV-1 envelope glycoproteins into virions. Second, Rab7A contributes to the mechanism that counteracts the restriction imposed on HIV-1 release by the cellular restriction factor BST2/Tetherin that physically tethers viral particles to the plasma membrane of infected cells. Altogether these data highlight new roles for a major player of the late endocytic pathway, Rab7A, in the late stages of the HIV-1 replication cycle.
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Affiliation(s)
- Marina Caillet
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Katy Janvier
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Annegret Pelchen–Matthews
- Cell Biology Unit, MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Delphine Delcroix-Genête
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Grégory Camus
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Mark Marsh
- Cell Biology Unit, MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Clarisse Berlioz-Torrent
- INSERM, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
- * E-mail:
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Flanagan ML, Parrish CR, Cobey S, Glass GE, Bush RM, Leighton TJ. Anticipating the species jump: surveillance for emerging viral threats. Zoonoses Public Health 2011; 59:155-63. [PMID: 21914152 PMCID: PMC4948863 DOI: 10.1111/j.1863-2378.2011.01439.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zoonotic disease surveillance is typically triggered after animal pathogens have already infected humans. Are there ways to identify high‐risk viruses before they emerge in humans? If so, then how and where can identifications be made and by what methods? These were the fundamental questions driving a workshop to examine the future of predictive surveillance for viruses that might jump from animals to infect humans. Virologists, ecologists and computational biologists from academia, federal government and non‐governmental organizations discussed opportunities as well as obstacles to the prediction of species jumps using genetic and ecological data from viruses and their hosts, vectors and reservoirs. This workshop marked an important first step towards envisioning both scientific and organizational frameworks for this future capability. Canine parvoviruses as well as seasonal H3N2 and pandemic H1N1 influenza viruses are discussed as exemplars that suggest what to look for in anticipating species jumps. To answer the question of where to look, prospects for discovering emerging viruses among wildlife, bats, rodents, arthropod vectors and occupationally exposed humans are discussed. Finally, opportunities and obstacles are identified and accompanied by suggestions for how to look for species jumps. Taken together, these findings constitute the beginnings of a conceptual framework for achieving a virus surveillance capability that could predict future species jumps.
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Affiliation(s)
- M L Flanagan
- College of Information Sciences and Technology, The Pennsylvania State University, State College, PA 16802, USA.
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30
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Late-penetrating viruses. Curr Opin Virol 2011; 1:35-43. [PMID: 22440565 DOI: 10.1016/j.coviro.2011.05.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 05/11/2011] [Accepted: 05/12/2011] [Indexed: 01/08/2023]
Abstract
Many enveloped and non-enveloped animal viruses delay the penetration into the cytosol of host cells until they have arrived to endocytic vacuoles deep in the cytoplasm. The late timing is generally determined by a low pH-threshold for the acid-activated penetration process (pH 6.2-4.9), but there can be a combination of other reasons for a delay. Since late-penetrating viruses (L-PVs) must be sorted into the degradative pathway, they are particularly sensitive to perturbations that interfere with molecular sorting and proper maturation of endosomes, including switching of Rabs, formation of intraluminal vesicles, and microtubule-mediated transport. In this short review, we focus on L-PVs from several virus families, and their interactions with the endocytic machinery.
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31
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Saeed MF, Kolokoltsov AA, Albrecht T, Davey RA. Cellular entry of ebola virus involves uptake by a macropinocytosis-like mechanism and subsequent trafficking through early and late endosomes. PLoS Pathog 2010; 6:e1001110. [PMID: 20862315 PMCID: PMC2940741 DOI: 10.1371/journal.ppat.1001110] [Citation(s) in RCA: 327] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Accepted: 08/17/2010] [Indexed: 12/17/2022] Open
Abstract
Zaire ebolavirus (ZEBOV), a highly pathogenic zoonotic virus, poses serious public health, ecological and potential bioterrorism threats. Currently no specific therapy or vaccine is available. Virus entry is an attractive target for therapeutic intervention. However, current knowledge of the ZEBOV entry mechanism is limited. While it is known that ZEBOV enters cells through endocytosis, which of the cellular endocytic mechanisms used remains unclear. Previous studies have produced differing outcomes, indicating potential involvement of multiple routes but many of these studies were performed using noninfectious surrogate systems such as pseudotyped retroviral particles, which may not accurately recapitulate the entry characteristics of the morphologically distinct wild type virus. Here we used replication-competent infectious ZEBOV as well as morphologically similar virus-like particles in specific infection and entry assays to demonstrate that in HEK293T and Vero cells internalization of ZEBOV is independent of clathrin, caveolae, and dynamin. Instead the uptake mechanism has features of macropinocytosis. The binding of virus to cells appears to directly stimulate fluid phase uptake as well as localized actin polymerization. Inhibition of key regulators of macropinocytosis including Pak1 and CtBP/BARS as well as treatment with the drug EIPA, which affects macropinosome formation, resulted in significant reduction in ZEBOV entry and infection. It is also shown that following internalization, the virus enters the endolysosomal pathway and is trafficked through early and late endosomes, but the exact site of membrane fusion and nucleocapsid penetration in the cytoplasm remains unclear. This study identifies the route for ZEBOV entry and identifies the key cellular factors required for the uptake of this filamentous virus. The findings greatly expand our understanding of the ZEBOV entry mechanism that can be applied to development of new therapeutics as well as provide potential insight into the trafficking and entry mechanism of other filoviruses. Filoviruses, including Zaire ebolavirus (ZEBOV), are among the most pathogenic viruses known. Our understanding of how these viruses enter into host cells is very limited. A deeper understanding of this process would enable the design of better targeted antiviral therapies. This study defines in detail, key steps of ZEBOV cellular uptake and trafficking into cells using wild type virus as well as the host factors that are responsible for permitting virus entry into cells. Our data indicated that the primary mechanism of ZEBOV uptake is a macropinocytosis-like process that delivers the virus to early endosomes and subsequently to late endosomes. These findings aid in our understanding of how filoviruses infect cells and suggest that disruption of macropinocytosis may be useful in treatment of infection.
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Affiliation(s)
- Mohammad F. Saeed
- Department of Microbiology & Immunology, 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
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Andrey A. Kolokoltsov
- Department of Microbiology & Immunology, 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
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Thomas Albrecht
- Department SK, Building 37, NASA, Houston, Texas, United States of America
| | - Robert A. Davey
- Department of Microbiology & Immunology, 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
- Institute of Human Infection and Immunity, The University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail:
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Lozach PY, Mancini R, Bitto D, Meier R, Oestereich L, Overby AK, Pettersson RF, Helenius A. Entry of bunyaviruses into mammalian cells. Cell Host Microbe 2010; 7:488-99. [PMID: 20542252 PMCID: PMC7172475 DOI: 10.1016/j.chom.2010.05.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2009] [Revised: 03/16/2010] [Accepted: 04/28/2010] [Indexed: 01/31/2023]
Abstract
The Bunyaviridae constitute a large family of enveloped animal viruses, many members of which cause serious diseases. However, early bunyavirus-host cell interactions and entry mechanisms remain largely uncharacterized. Investigating Uukuniemi virus, a bunyavirus of the genus Phlebovirus, we found that virus attachment to the cell surface was specific but inefficient, with 25% of bound viruses being endocytosed within 10 min, mainly via noncoated vesicles. The viruses entered Rab5a+ early endosomes and, subsequently, Rab7a+ and LAMP-1+ late endosomes. Acid-activated penetration, occurring 20-40 min after internalization, required maturation of early to late endosomes. The pH threshold for viral membrane fusion was 5.4, and entry was sensitive to temperatures below 25 degrees C. Together, our results indicate that Uukuniemi virus penetrates host cells by acid-activated membrane fusion from late endosomal compartments. This study also highlights the importance of the degradative branch of the endocytic pathway in facilitating entry of late-penetrating viruses.
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Affiliation(s)
- Pierre-Yves Lozach
- ETH Zurich, Institute of Biochemistry, Schafmattstrasse 18, CH-8093 Zurich, Switzerland
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Multiple pathways involved in porcine parvovirus cellular entry and trafficking toward the nucleus. J Virol 2010; 84:7782-92. [PMID: 20484503 DOI: 10.1128/jvi.00479-10] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Porcine parvovirus (PPV) is a major cause of reproductive failure in swine. The mechanisms implicated in the first steps of infection that lead to the delivery of the PPV genome to the nucleus are poorly understood. In the present work, a panel of chemical inhibitors was used to dissect the cellular mechanisms involved in establishing a PPV infection. The results demonstrated that following binding to sialic acids on cell surface glycoproteins, the virus used both clathrin-mediated endocytosis and macropinocytosis pathways to gain access into cells. Virus obtained from infected cells was present either as isolated particles or as aggregates, and these two forms could be separated by low-speed centrifugation. Isolated and purified particles strongly preferred entry by clathrin-mediated endocytosis, whereas aggregates clearly favored macropinocytosis. Subsequent endosomal acidification and traffic to the late endosomes were also shown to be essential for infection. The microtubule network was found to be important during the first 10 h of infection, whereas an intact actin network was required for almost the whole viral cycle. Proteasome processing was found to be essential, and capsid proteins were ubiquitinated relatively early during infection. Taken together, these results provided new insights into the first steps of PPV infection, including the use of alternative entry pathways, unique among members of this viral family.
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Binding site on the transferrin receptor for the parvovirus capsid and effects of altered affinity on cell uptake and infection. J Virol 2010; 84:4969-78. [PMID: 20200243 DOI: 10.1128/jvi.02623-09] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Canine parvovirus (CPV) and its relative feline panleukopenia virus (FPV) bind the transferrin receptor type 1 (TfR) to infect their host cells but show differences in the interactions with the feline and canine TfRs that determine viral host range and tissue tropism. We changed apical and protease-like domain residues by introducing point mutations and adding or removing glycosylation signals, and we then examined the interactions of those mutant TfRs with the capsids. Most substitutions had little effect on virus binding and uptake. However, mutations of several sites in the apical domain of the receptor either prevented binding to the capsids or reduced the affinity of receptor binding to various degrees. Glycans within the virus binding face of the apical domain also controlled capsid binding. CPV, but not the related feline parvovirus, could use receptors containing a canine TfR-specific glycosylation to mediate efficient infection, while addition of other N-linked glycosylation sites into the virus binding face of the feline apical domain reduced or eliminated both binding and infection. Replacement of critical feline TfR residue 221 with every amino acid had effects on binding and infection which were significantly associated with the biochemical properties of the residue replaced. Receptors with reduced affinities mostly showed proportional changes in their ability to mediate infection. Testing feline TfR variants for their binding and uptake patterns in cells showed that low-affinity versions bound fewer capsids and also differed in attachment to the cell surface and filopodia, but transport to the perinuclear endosome was similar.
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Parrish CR. Structures and functions of parvovirus capsids and the process of cell infection. Curr Top Microbiol Immunol 2010; 343:149-76. [PMID: 20397069 DOI: 10.1007/82_2010_33] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To infect a cell, the parvovirus or adeno-associated virus (AAV) genome must be delivered from outside the plasma membrane to the nucleus, and in the process, the capsid must follow a series of binding and trafficking steps and also undergo necessary changes that result in exposure or release the ssDNA genome at the appropriate time and place within the cell. The 25 nm parvovirus capsid is comprised of two or three forms of a single protein, and although it is robust and stable, it is still sufficiently flexible to allow the exposure of several internal components at appropriate times during cell infection. The capsid can also accommodate insertion of peptides into surface loops, and capsid proteins from different viral serotypes can be shuffled to create novel functional variants. The capsids of the different viruses bind to one or more cell receptors, and for at least some viruses, the insertion of additional or alternative receptor binding sequences or structures into the capsid can expand or redirect its tropism. The infection process after cell binding involves receptor-mediated endocytosis followed by viral trafficking through the endosomal systems. That endosomal trafficking may be complex and prolonged for hours or be relatively brief. Generally only a small proportion of the particles taken up enter the cytoplasm after altering the endosomal membrane through the activity of a VP1-encoded phospholipase A2 domain that becomes released to the outside of the viral particle. Modifications to the capsid that can occur within the endosome or cytoplasm include structural changes to expose internal components, ubiquination and proteosomal processing, and possible trafficking of particles on molecular motors. It is still not clear how the genomes enter the nucleus, but nuclear pore-dependent entry of particles or permeabilization of nuclear membranes have been proposed. Those processes control the infection, pathogenesis, and host ranges of the autonomous viruses and determine the effectiveness of gene therapy using AAV capsids.
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Affiliation(s)
- Colin R Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY, 14853, USA.
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