Analysis of Factors That Regulate HIV-1 Fusion in Reverse
Based on observations that HIV-1 envelope (Env) proteins on the surfaces of cells have the capacity to fuse with neighboring cells or enveloped viruses that express CD4 receptors and CXCR4 co-receptors, we tested factors that affect the capacities of lentiviral vectors pseudotyped with CD4 and CXCR4...
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MDPI AG
2025-03-01
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| Online Access: | https://www.mdpi.com/1999-4915/17/4/472 |
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| author | Ayna Alfadhli Robin Lid Barklis Fikadu G. Tafesse Eric Barklis |
| author_facet | Ayna Alfadhli Robin Lid Barklis Fikadu G. Tafesse Eric Barklis |
| author_sort | Ayna Alfadhli |
| collection | DOAJ |
| description | Based on observations that HIV-1 envelope (Env) proteins on the surfaces of cells have the capacity to fuse with neighboring cells or enveloped viruses that express CD4 receptors and CXCR4 co-receptors, we tested factors that affect the capacities of lentiviral vectors pseudotyped with CD4 and CXCR4 variants to infect Env-expressing cells. The process, which we refer to as fusion in reverse, involves the binding and activation of cellular Env proteins to fuse membranes with lentiviruses carrying CD4 and CXCR4 proteins. We have found that infection via fusion in reverse depends on cell surface Env levels, is inhibitable by an HIV-1-specific fusion inhibitor, and preferentially requires lentiviral pseudotyping with a glycosylphosphatidylinositol (GPI)-anchored CD4 variant and a cytoplasmic tail-truncated CXCR4 protein. We have demonstrated that latently HIV-1-infected cells can be specifically infected using this mechanism, and that activation of latently infected cells increases infection efficiency. The fusion in reverse approach allowed us to characterize how alteration of CD4 plus CXCR4 lipid membranes affected Env protein activities. In particular, we found that perturbation of membrane cholesterol levels did not affect Env activity. In contrast, viruses assembled in cells deficient for long-chain sphingolipids showed increased infectivities, while viruses that incorporated a lipid scramblase were non-infectious. Our results yield new insights into factors that influence envelope protein functions. |
| format | Article |
| id | doaj-art-9398d089135e473b938f933de6820b13 |
| institution | DOAJ |
| issn | 1999-4915 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Viruses |
| spelling | doaj-art-9398d089135e473b938f933de6820b132025-08-20T03:13:33ZengMDPI AGViruses1999-49152025-03-0117447210.3390/v17040472Analysis of Factors That Regulate HIV-1 Fusion in ReverseAyna Alfadhli0Robin Lid Barklis1Fikadu G. Tafesse2Eric Barklis3Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USADepartment of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USADepartment of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USADepartment of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USABased on observations that HIV-1 envelope (Env) proteins on the surfaces of cells have the capacity to fuse with neighboring cells or enveloped viruses that express CD4 receptors and CXCR4 co-receptors, we tested factors that affect the capacities of lentiviral vectors pseudotyped with CD4 and CXCR4 variants to infect Env-expressing cells. The process, which we refer to as fusion in reverse, involves the binding and activation of cellular Env proteins to fuse membranes with lentiviruses carrying CD4 and CXCR4 proteins. We have found that infection via fusion in reverse depends on cell surface Env levels, is inhibitable by an HIV-1-specific fusion inhibitor, and preferentially requires lentiviral pseudotyping with a glycosylphosphatidylinositol (GPI)-anchored CD4 variant and a cytoplasmic tail-truncated CXCR4 protein. We have demonstrated that latently HIV-1-infected cells can be specifically infected using this mechanism, and that activation of latently infected cells increases infection efficiency. The fusion in reverse approach allowed us to characterize how alteration of CD4 plus CXCR4 lipid membranes affected Env protein activities. In particular, we found that perturbation of membrane cholesterol levels did not affect Env activity. In contrast, viruses assembled in cells deficient for long-chain sphingolipids showed increased infectivities, while viruses that incorporated a lipid scramblase were non-infectious. Our results yield new insights into factors that influence envelope protein functions.https://www.mdpi.com/1999-4915/17/4/472HIV-1fusionlipidmembranes |
| spellingShingle | Ayna Alfadhli Robin Lid Barklis Fikadu G. Tafesse Eric Barklis Analysis of Factors That Regulate HIV-1 Fusion in Reverse Viruses HIV-1 fusion lipid membranes |
| title | Analysis of Factors That Regulate HIV-1 Fusion in Reverse |
| title_full | Analysis of Factors That Regulate HIV-1 Fusion in Reverse |
| title_fullStr | Analysis of Factors That Regulate HIV-1 Fusion in Reverse |
| title_full_unstemmed | Analysis of Factors That Regulate HIV-1 Fusion in Reverse |
| title_short | Analysis of Factors That Regulate HIV-1 Fusion in Reverse |
| title_sort | analysis of factors that regulate hiv 1 fusion in reverse |
| topic | HIV-1 fusion lipid membranes |
| url | https://www.mdpi.com/1999-4915/17/4/472 |
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