Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers
Increased knowledge of virus assembly-generated particles is needed for understanding both virus assembly and host responses to virus infection. Here, we use a phage T3 model and perform electron microscopy (EM) of thin sections (EM-TS) of gel-supported T3 plaques formed at 30 °C. After ura...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-01-01
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| Series: | Pharmaceuticals |
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| Online Access: | https://www.mdpi.com/1424-8247/13/1/18 |
| _version_ | 1818336498087362560 |
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| author | Philip Serwer Barbara Hunter Elena T. Wright |
| author_facet | Philip Serwer Barbara Hunter Elena T. Wright |
| author_sort | Philip Serwer |
| collection | DOAJ |
| description | Increased knowledge of virus assembly-generated particles is needed for understanding both virus assembly and host responses to virus infection. Here, we use a phage T3 model and perform electron microscopy (EM) of thin sections (EM-TS) of gel-supported T3 plaques formed at 30 °C. After uranyl acetate/lead staining, we observe intracellular black particles, some with a difficult-to-see capsid. Some black particles (called LBPs) are larger than phage particles. The LBP frequency is increased by including proflavine, a DNA packaging inhibitor, in the growth medium and increasing plaque-forming temperature to 37 °C. Acidic phosphotungstate-precipitate (A-PTA) staining causes LBP substitution by black rings (BRs) that have the size and shape expected of hyper-expanded capsid containers for LBP DNA. BRs are less frequent in liquid cultures, suggesting that hyper-expanded capsids evolved primarily for in-gel (e.g., in-biofilm) propagation. BR-specific A-PTA staining and other observations are explained by α-sheet intense structure of the major subunit of hyper-expanded capsids. We hypothesize that herpes virus triggering of neurodegenerative disease occurs via in-gel propagation-promoted (1) generation of α-sheet intense viral capsids and, in response, (2) host production of α-sheet intense, capsid-interactive, innate immunity amyloid protein that becomes toxic. We propose developing viruses that are therapeutic via detoxifying interaction with this innate immunity protein. |
| first_indexed | 2024-12-13T14:40:16Z |
| format | Article |
| id | doaj.art-9c0dc848bd3442a583a29af0b05c6a42 |
| institution | Directory Open Access Journal |
| issn | 1424-8247 |
| language | English |
| last_indexed | 2024-12-13T14:40:16Z |
| publishDate | 2020-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Pharmaceuticals |
| spelling | doaj.art-9c0dc848bd3442a583a29af0b05c6a422022-12-21T23:41:38ZengMDPI AGPharmaceuticals1424-82472020-01-011311810.3390/ph13010018ph13010018Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease TriggersPhilip Serwer0Barbara Hunter1Elena T. Wright2Department of Biochemistry and Structural Biology, The University of Texas Health Science Center, San Antonio, TX 78229–3900, USADepartment of Pathology, The University of Texas Health Science Center, San Antonio, TX 78229–3900, USADepartment of Biochemistry and Structural Biology, The University of Texas Health Science Center, San Antonio, TX 78229–3900, USAIncreased knowledge of virus assembly-generated particles is needed for understanding both virus assembly and host responses to virus infection. Here, we use a phage T3 model and perform electron microscopy (EM) of thin sections (EM-TS) of gel-supported T3 plaques formed at 30 °C. After uranyl acetate/lead staining, we observe intracellular black particles, some with a difficult-to-see capsid. Some black particles (called LBPs) are larger than phage particles. The LBP frequency is increased by including proflavine, a DNA packaging inhibitor, in the growth medium and increasing plaque-forming temperature to 37 °C. Acidic phosphotungstate-precipitate (A-PTA) staining causes LBP substitution by black rings (BRs) that have the size and shape expected of hyper-expanded capsid containers for LBP DNA. BRs are less frequent in liquid cultures, suggesting that hyper-expanded capsids evolved primarily for in-gel (e.g., in-biofilm) propagation. BR-specific A-PTA staining and other observations are explained by α-sheet intense structure of the major subunit of hyper-expanded capsids. We hypothesize that herpes virus triggering of neurodegenerative disease occurs via in-gel propagation-promoted (1) generation of α-sheet intense viral capsids and, in response, (2) host production of α-sheet intense, capsid-interactive, innate immunity amyloid protein that becomes toxic. We propose developing viruses that are therapeutic via detoxifying interaction with this innate immunity protein.https://www.mdpi.com/1424-8247/13/1/18assembly-generated particlesobscurephage capsidsprotein stainingprotein structurethin sections |
| spellingShingle | Philip Serwer Barbara Hunter Elena T. Wright Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers Pharmaceuticals assembly-generated particles obscure phage capsids protein staining protein structure thin sections |
| title | Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers |
| title_full | Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers |
| title_fullStr | Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers |
| title_full_unstemmed | Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers |
| title_short | Electron Microscopy of In-Plaque Phage T3 Assembly: Proposed Analogs of Neurodegenerative Disease Triggers |
| title_sort | electron microscopy of in plaque phage t3 assembly proposed analogs of neurodegenerative disease triggers |
| topic | assembly-generated particles obscure phage capsids protein staining protein structure thin sections |
| url | https://www.mdpi.com/1424-8247/13/1/18 |
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