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Journal of Virology Nov 1998Vectors derived from human immunodeficiency virus (HIV) are highly efficient vehicles for in vivo gene delivery. However, their biosafety is of major concern. Here we...
Vectors derived from human immunodeficiency virus (HIV) are highly efficient vehicles for in vivo gene delivery. However, their biosafety is of major concern. Here we exploit the complexity of the HIV genome to provide lentivirus vectors with novel biosafety features. In addition to the structural genes, HIV contains two regulatory genes, tat and rev, that are essential for HIV replication, and four accessory genes that encode critical virulence factors. We previously reported that the HIV type 1 accessory open reading frames are dispensable for efficient gene transduction by a lentivirus vector. We now demonstrate that the requirement for the tat gene can be offset by placing constitutive promoters upstream of the vector transcript. Vectors generated from constructs containing such a chimeric long terminal repeat (LTR) transduced neurons in vivo at very high efficiency, whether or not they were produced in the presence of Tat. When the rev gene was also deleted from the packaging construct, expression of gag and pol was strictly dependent on Rev complementation in trans. By the combined use of a separate nonoverlapping Rev expression plasmid and a 5' LTR chimeric transfer construct, we achieved optimal yields of vector of high transducing efficiency (up to 10(7) transducing units [TU]/ml and 10(4) TU/ng of p24). This third-generation lentivirus vector uses only a fractional set of HIV genes: gag, pol, and rev. Moreover, the HIV-derived constructs, and any recombinant between them, are contingent on upstream elements and trans complementation for expression and thus are nonfunctional outside of the vector producer cells. This split-genome, conditional packaging system is based on existing viral sequences and acts as a built-in device against the generation of productive recombinants. While the actual biosafety of the vector will ultimately be proven in vivo, the improved design presented here should facilitate testing of lentivirus vectors.
Topics: Animals; Base Sequence; Brain; DNA Primers; Genes, Reporter; Genes, rev; Genes, tat; Genetic Therapy; Genetic Vectors; Genome, Viral; HIV-1; HeLa Cells; Humans; Lentivirus; Male; Polymerase Chain Reaction; Promoter Regions, Genetic; Rats; Rats, Inbred F344; Safety; Transduction, Genetic
PubMed: 9765382
DOI: 10.1128/JVI.72.11.8463-8471.1998 -
Frontiers in Microbiology 2016Despite its small genome size, the Human Immunodeficiency Virus 1 (HIV-1) is one of the most successful pathogens and has infected more than 70 million people worldwide... (Review)
Review
Despite its small genome size, the Human Immunodeficiency Virus 1 (HIV-1) is one of the most successful pathogens and has infected more than 70 million people worldwide within the last decades. In total, HIV-1 expresses 16 canonical proteins from only nine genes within its 10 kb genome. Expression of the structural genes , and , the regulatory genes and and the accessory genes , , and enables assembly of the viral particle, regulates viral gene transcription, and equips the virus to evade or counteract host immune responses. In addition to the canonically expressed proteins, a growing number of publications describe the existence of non-canonical fusion proteins in HIV-1 infected cells. Most of them are encoded by the -- locus. While the majority of these fusion proteins (e.g., TNV/p28 , p18, Tat1-Rev2, Tat^8c, p17, or Ref) are the result of alternative splicing events, Tat-T/Vpt is produced upon programmed ribosomal frameshifting, and a Rev1-Vpu fusion protein is expressed due to a nucleotide polymorphism that is unique to certain HIV-1 clade A and C strains. A better understanding of the expression and activity of these non-canonical viral proteins will help to dissect their potential role in viral replication and reveal how HIV-1 optimized the coding potential of its genes. The goal of this review is to provide an overview of previously described HIV-1 fusion proteins and to summarize our current knowledge of their expression patterns and putative functions.
PubMed: 28119676
DOI: 10.3389/fmicb.2016.02152 -
Frontiers in Cellular and Infection... 2020HIV Tat protein is a critical protein that plays multiple roles in HIV pathogenesis. While its role as the transactivator of HIV transcription is well-established, other... (Review)
Review
HIV Tat protein is a critical protein that plays multiple roles in HIV pathogenesis. While its role as the transactivator of HIV transcription is well-established, other non-viral replication-associated functions have been described in several HIV-comorbidities even in the current antiretroviral therapy (ART) era. HIV Tat protein is produced and released into the extracellular space from cells with active HIV replication or from latently HIV-infected cells into neighboring uninfected cells even in the absence of active HIV replication and viral production due to effective ART. Neighboring uninfected and HIV-infected cells can take up the released Tat resulting in the upregulation of inflammatory genes and activation of pathways that leads to cytotoxicity observed in several comorbidities such as HIV associated neurocognitive disorder (HAND), HIV associated cardiovascular impairment, and accelerated aging. Thus, understanding how Tat modulates host and viral response is important in designing novel therapeutic approaches to target the chronic inflammatory effects of soluble viral proteins in HIV infection.
Topics: HIV Infections; HIV-1; Humans; tat Gene Products, Human Immunodeficiency Virus
PubMed: 32158701
DOI: 10.3389/fcimb.2020.00061 -
Microbes and Infection Apr 2006HIV tat is the transactivator of HIV-1, supporting efficient viral replication by stabilizing the transcription of viral genes. Tat can be released from HIV-infected... (Review)
Review
HIV tat is the transactivator of HIV-1, supporting efficient viral replication by stabilizing the transcription of viral genes. Tat can be released from HIV-infected cells and alter several functions in uninfected cells. In the brain, tat induces neuronal dysfunction/toxicity, even though neurons cannot be directly infected with HIV, resulting in CNS pathology, such as the dementia and encephalitis associated with NeuroAIDS. This review discusses the most recent data addressing tat-induced neurotoxicity and integrates these new findings in the context of NeuroAIDS.
Topics: AIDS Dementia Complex; Apoptosis; Brain; Chemokine CCL2; Encephalitis, Viral; Gene Products, tat; HIV Infections; Humans; Neurons; tat Gene Products, Human Immunodeficiency Virus
PubMed: 16697675
DOI: 10.1016/j.micinf.2005.11.014 -
Retrovirology Aug 2006The SWI/SNF chromatin remodeling complex is an essential regulator of transcription of cellular genes. HIV-1 infection induces exit of a core component of SWI/SNF, Ini1,...
The SWI/SNF chromatin remodeling complex is an essential regulator of transcription of cellular genes. HIV-1 infection induces exit of a core component of SWI/SNF, Ini1, into the cytoplasm and its association with the viral pre-integration complex. Several recent papers published in EMBO Journal, Journal of Biological Chemistry, and Retrovirology provide new information regarding possible functions of Ini1 and SWI/SNF in HIV life cycle. It appears that Ini1 has an inhibitory effect on pre-integration steps of HIV replication, but also contributes to stimulation of Tat-mediated transcription. This stimulation involves displacement of the nucleosome positioned at the HIV promoter.
Topics: Chromatin Assembly and Disassembly; Chromosomal Proteins, Non-Histone; DNA-Binding Proteins; Gene Products, tat; HIV Long Terminal Repeat; HIV-1; Humans; SMARCB1 Protein; Transcription Factors; Transcription, Genetic; Virus Replication; tat Gene Products, Human Immunodeficiency Virus
PubMed: 16899112
DOI: 10.1186/1742-4690-3-49 -
Epigenomics Mar 2022To understand the effect of HIV infection and cocaine exposure on piRNA expression in human primary astrocytes. We used small RNA sequencing analysis to investigate...
To understand the effect of HIV infection and cocaine exposure on piRNA expression in human primary astrocytes. We used small RNA sequencing analysis to investigate the impacts of HIV-1 Tat and cocaine coexposure on the expression of piRNAs in human primary astrocytes. We identified 27,700 piRNAs and analyzed them by small RNA next-generation sequencing. A total of 239 piRNAs were significantly altered by HIV-1 Tat and cocaine coexposure. We also identified PIWIL1, PIWIL2, PIWIL3 and PIWIL4 as interacting partners of piRNAs that were affected by cocaine and HIV-1 Tat coexposure. Epigenetic changes in the expression levels of these piRNA targets were associated with Kyoto Encyclopedia of Genes and Genomes pathways of energy metabolism and neurodegeneration. These findings provide evidence that cocaine exposure and HIV infection affect the expression levels of piRNA, PIWIL1, PIWIL2, PIWIL3 and PIWIL4.
Topics: Argonaute Proteins; Astrocytes; Cocaine; Energy Metabolism; HIV Infections; HIV-1; Humans; RNA, Small Interfering
PubMed: 35170353
DOI: 10.2217/epi-2021-0252 -
Frontiers in Microbiology 2017Despite the effective use of antiretroviral therapy, the remainder of a latently HIV-1-infected reservoir mainly in the resting memory CD4 T lymphocyte subset has... (Review)
Review
Despite the effective use of antiretroviral therapy, the remainder of a latently HIV-1-infected reservoir mainly in the resting memory CD4 T lymphocyte subset has provided a great setback toward viral eradication. While host transcriptional silencing machinery is thought to play a dominant role in HIV-1 latency, HIV-1 protein such as Tat, may affect both the establishment and the reversal of latency. Indeed, mutational studies have demonstrated that insufficient Tat transactivation activity can result in impaired transcription of viral genes and the establishment of latency in cell culture experiments. Because Tat protein is one of highly variable proteins within HIV-1 proteome, it is conceivable that naturally occurring Tat mutations may differentially modulate Tat functions, thereby influencing the establishment and/or the reversal of viral latency In this mini review, we summarize the recent findings of Tat naturally occurring polymorphisms associating with host immune responses and we highlight the implication of Tat sequence variations in relation to HIV latency.
PubMed: 28194140
DOI: 10.3389/fmicb.2017.00080 -
Cold Spring Harbor Perspectives in... Feb 2012Control of HIV-1 gene expression depends on two viral regulatory proteins, Tat and Rev. Tat stimulates transcription elongation by directing the cellular transcriptional... (Review)
Review
Control of HIV-1 gene expression depends on two viral regulatory proteins, Tat and Rev. Tat stimulates transcription elongation by directing the cellular transcriptional elongation factor P-TEFb to nascent RNA polymerases. Rev is required for the transport from the nucleus to the cytoplasm of the unspliced and incompletely spliced mRNAs that encode the structural proteins of the virus. Molecular studies of both proteins have revealed how they interact with the cellular machinery to control transcription from the viral LTR and regulate the levels of spliced and unspliced mRNAs. The regulatory feedback mechanisms driven by HIV-1 Tat and Rev ensure that HIV-1 transcription proceeds through distinct phases. In cells that are not fully activated, limiting levels of Tat and Rev act as potent blocks to premature virus production.
Topics: Feedback, Physiological; Gene Expression; Genes, Suppressor; HIV Infections; HIV-1; Humans; Polyadenylation; RNA Splicing; RNA, Viral; Transcription Factors; Transcription, Genetic; Virus Activation; Virus Replication; rev Gene Products, Human Immunodeficiency Virus; tat Gene Products, Human Immunodeficiency Virus
PubMed: 22355797
DOI: 10.1101/cshperspect.a006916 -
Cell Reports May 2022Cocaine use is a major comorbidity of HIV-associated neurocognitive disorder (HAND). In this study, we show that cocaine exposure worsens the learning and memory of...
Cocaine use is a major comorbidity of HIV-associated neurocognitive disorder (HAND). In this study, we show that cocaine exposure worsens the learning and memory of doxycycline-inducible and brain-specific HIV Tat transgenic mice (iTat) and results in 14,838 hypermethylated CpG-related differentially methylated regions (DMRs) and 15,800 hypomethylated CpG-related DMRs, which are linked to 52 down- and 127 upregulated genes, respectively, in the hippocampus of iTat mice. These genes are mostly enriched at the neuronal function-, cell morphology-, and synapse formation-related extracellular matrix (ECM) receptor-ligand interaction pathway and mostly impacted in microglia. The accompanying neuropathological changes include swollen dendritic spines, increased synaptophysin expression, and diminished glial activation. We also find that sex (female) and age additively worsen the behavioral and pathological changes. These findings together indicate that chronic cocaine and long-term Tat expression interactively contribute to HAND, likely involving changes of DNA methylation and ECM receptor-ligand interactions.
Topics: Animals; Cocaine; DNA; DNA Methylation; Female; Gene Expression; Ligands; Memory Disorders; Mice; Mice, Transgenic; tat Gene Products, Human Immunodeficiency Virus
PubMed: 35508123
DOI: 10.1016/j.celrep.2022.110765 -
AIDS Research and Therapy Nov 2023Human immunodeficiency virus (HIV) infection is associated with an elevated incidence of cervical cancer, and accelerated disease progression, but the underlying...
BACKGROUND
Human immunodeficiency virus (HIV) infection is associated with an elevated incidence of cervical cancer, and accelerated disease progression, but the underlying mechanisms are not well understood. This study aimed to investigate the relationship between HIV infection and epithelial-mesenchymal transition (EMT) in cervical cancer.
METHODS
Tissue samples from HIV-positive and negative patients with cervical intraepithelial neoplasia (CIN) and cervical cancer were analyzed for EMT-related proteins. Human cervical cancer SiHa cells were treated with HIV Tat and gp120 proteins to test their effects on EMT, migration, and invasion.
RESULTS
HIV-positive patients had lower E-cadherin and cytokeratin, and higher N-cadherin and vimentin levels than HIV-negative patients. HIV Tat and gp120 proteins induced EMT, migration, and invasion in SiHa cells. Transcriptome sequencing analysis revealed that, compared to the control group, the protein-treated group showed upregulation of 22 genes and downregulation of 77 genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed the involvement of the Wnt signaling pathway in EMT. Further analysis of gene expression related to this pathway revealed upregulation of DVL1, TCF7, KRT17, and VMAC, while GSK3β, SFRP2, and CDH1 were downregulated. Immunofluorescence assay demonstrated that HIVgp120 and Tat proteins treatment induced elevated β-catenin expression with nuclear accumulation in SiHa cells.
CONCLUSIONS
The treatment of SiHa cells with HIV Tat and gp120 proteins induces EMT and activates the Wnt/β-catenin pathway, suggesting that the Wnt/β-catenin pathway may play a crucial role in promoting EMT progression in cervical lesion tissues of HIV-infected patients.
Topics: Female; Humans; beta Catenin; Uterine Cervical Neoplasms; Cell Line, Tumor; Gene Products, tat; Epithelial-Mesenchymal Transition; HIV Infections
PubMed: 37981694
DOI: 10.1186/s12981-023-00577-1