Genetic analysis of the Human Immunodeficiency Virus type 1 integrase protein.

Division of Human Retrovirology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Journal of Virology (Impact Factor: 4.44). 04/1994; 68(3):1633-42.
Source: PubMed


Single-amino-acid changes in a highly conserved central region of the human immunodeficiency virus type 1 (HIV-1) integrase protein were analyzed for their effects on viral protein synthesis, virion morphogenesis, and viral replication. Alteration of two amino acids that are invariant among retroviral integrases, D116 and E152 of HIV-1, as well as a mutation of the highly conserved amino acid S147 blocked viral replication in two CD4+ human T-cell lines. Mutations of four other highly conserved amino acids in the region had no detectable effect on viral replication, whereas mutations at two positions, N117 and Y143, resulted in viruses with a delayed-replication phenotype. Defects in virion precursor polypeptide processing, virion morphology, or viral DNA synthesis were observed for all of the replication-defective mutants, indicating that changes in integrase can have pleiotropic effects on viral replication.

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Available from: Chris M. Farnet, Aug 27, 2014
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    • "Certain IN mutants have a profound effect on reverse transcription, but do not affect the RT activity in viral lysates, suggesting an exclusive impact in the context of the virion particle. In addition, IN mutant viruses can be affected in a variety of processes, including integration, assembly and viral core morphology [45]–[48]. These combined results indicate that protein and RNA processing are intricately linked during virion assembly and maturation. "
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    ABSTRACT: The viral integrase (IN) is an essential protein for HIV-1 replication. IN inserts the viral dsDNA into the host chromosome, thereby aided by the cellular co-factor LEDGF/p75. Recently a new class of integrase inhibitors was described: allosteric IN inhibitors (ALLINIs). Although designed to interfere with the IN-LEDGF/p75 interaction to block HIV DNA integration during the early phase of HIV-1 replication, the major impact was surprisingly found on the process of virus maturation during the late phase, causing a reverse transcription defect upon infection of target cells. Virus particles produced in the presence of an ALLINI are misformed with the ribonucleoprotein located outside the virus core. Virus assembly and maturation are highly orchestrated and regulated processes in which several viral proteins and RNA molecules closely interact. It is therefore of interest to study whether ALLINIs have unpredicted pleiotropic effects on these RNA-related processes. We confirm that the ALLINI BI-D inhibits virus replication and that the produced virus is non-infectious. Furthermore, we show that the wild-type level of HIV-1 genomic RNA is packaged in virions and these genomes are in a dimeric state. The tRNAlys3 primer for reverse transcription was properly placed on this genomic RNA and could be extended ex vivo. In addition, the packaged reverse transcriptase enzyme was fully active when extracted from virions. As the RNA and enzyme components for reverse transcription are properly present in virions produced in the presence of BI-D, the inhibition of reverse transcription is likely to reflect the mislocalization of the components in the aberrant virus particle.
    Full-text · Article · Jul 2014 · PLoS ONE
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    • "Although the enzymatic activities of HIV-1 IN in the integration reaction have been clearly defined by in vitro biochemical studies, numerous genetic analysis of HIV-1 DNA have demonstrated that mutations in the IN gene, including deletion mutants, influence many other stages of viral replication in addition to integration. This pleiotropic effect of IN is characterized by defects in uncoating, reverse transcription, nuclear import, viral gene expression, virion precursor protein processing, and virion morphology (Shin et al., 1994; Engelman et al., 1995; Masuda et al., 1995; Bukovsky & Gottlinger, 1996; Leavitt et al., 1996; Nakamura et al., 1997; Engelman, 1999; Tsurutani et al., 2000; Lu et al., 2004; Dar et al., 2009; Briones et al., 2010). However, the mechanisms for these pleiotropic effects of the IN gene are still poorly understood. "

    Full-text · Chapter · Nov 2011
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    • "Since IN is expressed as part of Gag-Pol, agents that bind to the IN domain in this polyprotein are likely to impact on the late stages of replication. Consistent with this notion, mutations in IN have been reported to effect virion formation (Shin et al. 1994). Truncations of IN at the C-terminus of Gag-Pol result in aberrant virion core structures, with a reduction in the overall levels of cell-associated viral Gag, suggesting a defect in Gag-Pol processing (Engelman et al. 1995; Bukovsky and Gottlinger, 1996). "
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    ABSTRACT: The targets for licensed drugs used for the treatment of human immunodeficiency virus type 1 (HIV-1) are confined to the viral reverse transcriptase (RT), protease (PR), and the gp41 transmembrane protein (TM). While currently approved drugs are effective in controlling HIV-1 infections, new drug targets and agents are needed due to the eventual emergence of drug resistant strains and drug toxicity. Our increased understanding of the virus life-cycle and how the virus interacts with the host cell has unveiled novel mechanisms for blocking HIV-1 replication. This review focuses on inhibitors that target the late stages of virus replication including the synthesis and trafficking of the viral polyproteins, viral assembly, maturation and budding. Novel approaches to blocking the oligomerization of viral enzymes and the interactions between viral proteins and host cell factors, including their feasibility as drug targets, are discussed.
    Full-text · Article · Jul 2007 · Drug Target Insights
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