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Biochemistry May 2003The retroviral integrase (IN) carries out the integration of the viral DNA into the host genome. Both IN and the DNA sequences at the viral long-terminal repeat (LTR)...
The retroviral integrase (IN) carries out the integration of the viral DNA into the host genome. Both IN and the DNA sequences at the viral long-terminal repeat (LTR) are required for the integration function. In this report, a series of minor groove binding hairpin polyamides targeting sequences within terminal inverted repeats of the Moloney murine leukemia virus (M-MuLV) LTR were synthesized, and their effects on integration were analyzed. Using cell-free in vitro integration assays, polyamides targeting the conserved CA dinucleotide with cognate sites closest to the terminal base pairs were effective at blocking 3' processing but not strand transfer. Polyamides which efficiently inhibited 3' processing and strand transfer targeted the LTR sequences through position 9. Polyamides that inhibited integration were effective at nanomolar concentrations and showed subnanomolar affinity for their cognate LTR sites. These studies highlight the role of minor groove interactions within the LTR termini for retroviral integration.
Topics: Animals; Base Sequence; Binding Sites; DNA, Viral; Drug Design; In Vitro Techniques; Kinetics; Mice; Moloney murine leukemia virus; Nylons; Terminal Repeat Sequences; Virus Integration
PubMed: 12755629
DOI: 10.1021/bi034177s -
Sub-cellular Biochemistry 2018Integration of a DNA copy of the viral genome into host DNA is an essential step in the replication cycle of HIV-1 and other retroviruses and is an important therapeutic... (Review)
Review
Integration of a DNA copy of the viral genome into host DNA is an essential step in the replication cycle of HIV-1 and other retroviruses and is an important therapeutic target for drugs. DNA integration is catalyzed by the viral integrase protein and proceeds through a series of stable nucleoprotein complexes of integrase, viral DNA ends and target DNA. These nucleoprotein complexes are collectively called intasomes. Retroviral intasomes undergo a series of transitions between initial formation and catalysis of the DNA cutting and joining steps of DNA integration. Intasomes, rather than free integrase protein, are the target of currently approved drugs that target HIV-1 DNA integration. High-resolution structures of HIV-1 intasomes are needed to understand their detailed mechanism of action and how HIV-1 may escape by developing resistance. Here, we focus on our current knowledge of the structure and function of HIV-1 intasomes, with reference to related systems as required to put this knowledge in context.
Topics: Animals; DNA, Viral; HIV-1; Humans; Nucleoproteins; Structure-Activity Relationship; Virus Integration
PubMed: 29900498
DOI: 10.1007/978-981-10-8456-0_9 -
Cell Host & Microbe Dec 2016Integration is a key feature of the retroviral life cycle. This process involves packaging of the viral genome into chromatin, which is often assumed to occur as a...
Integration is a key feature of the retroviral life cycle. This process involves packaging of the viral genome into chromatin, which is often assumed to occur as a post-integration step. In this issue of Cell Host & Microbe, Wang and colleagues (Wang et al., 2016) show that chromatinization occurs before integration, raising new questions about the role of histones in retroviral integration and transcription.
Topics: Acetylation; Animals; Capsid Proteins; Cell Line, Tumor; Chromatin; DNA, Viral; Embryonal Carcinoma Stem Cells; Epigenomics; Fibroblasts; Gene Expression Regulation, Viral; Histones; Humans; Infections; Life Cycle Stages; Mice; Mouse Embryonic Stem Cells; Nucleocapsid Proteins; Retroviridae; Retroviridae Infections; Transcription, Genetic; Virus Assembly; Virus Integration
PubMed: 27978432
DOI: 10.1016/j.chom.2016.11.003 -
Proceedings of the National Academy of... Nov 2021
Topics: COVID-19; COVID-19 Testing; Genome, Human; Humans; RNA, Viral; Real-Time Polymerase Chain Reaction; SARS-CoV-2; Virus Integration
PubMed: 34702741
DOI: 10.1073/pnas.2113065118 -
FEBS Letters Jul 2016Thanks to the current combined antiretroviral therapy (cART), HIV-1 infection has become a manageable although chronic disease. The reason for this lies in the fact that... (Review)
Review
Thanks to the current combined antiretroviral therapy (cART), HIV-1 infection has become a manageable although chronic disease. The reason for this lies in the fact that long-lived cellular reservoirs persist in patients on cART. Despite numerous efforts to understand molecular mechanisms that contribute to viral latency, the important question of how and when latency is established remains unanswered. Related to this is the connection between HIV-1 integration and the capacity of the provirus to enter the latent state. In this review, we will give an overview of these nuclear events in the viral life cycle in the light of current therapeutic approaches, which aim to either reactivate the provirus or even excise the proviral DNA from the cellular genome.
Topics: Animals; Chromatin; Disease Reservoirs; HIV Infections; HIV-1; Humans; Transcription, Genetic; Virus Integration
PubMed: 27224516
DOI: 10.1002/1873-3468.12226 -
Journal of Virology Feb 2008Based on integration site preferences, retroviruses can be placed into three groups. Viruses that comprise the first group, murine leukemia virus and foamy virus,... (Comparative Study)
Comparative Study
Based on integration site preferences, retroviruses can be placed into three groups. Viruses that comprise the first group, murine leukemia virus and foamy virus, integrate preferentially near transcription start sites. The second group, notably human immunodeficiency virus and simian immunodeficiency virus, preferentially targets transcription units. Avian sarcoma-leukosis virus (ASLV) and human T-cell leukemia virus (HTLV), forming the third group, show little preference for any genomic feature. We have previously shown that some human cells sustain mouse mammary tumor virus (MMTV) infection; therefore, we infected a susceptible human breast cell line, Hs578T, and, without introducing a species-specific bias, compared the MMTV integration profile to those of other retroviruses. Additionally, we infected a mouse cell line, NMuMG, and thus we could compare MMTV integration site selection in human and mouse cells. In total, we examined 468 unique MMTV integration sites. Irrespective of whether human or mouse cells were infected, no integration bias favoring transcription start sites was detected, a profile that is reminiscent of that of ASLV and HTLV. However, in contrast to ASLV and HTLV, not even a modest tendency in favor of integration within genes was observed. Similarly, repetitive sequences and genes that are frequently tagged by MMTV in mammary tumors were not preferentially targeted in cell culture either in mouse or in human cells; hence, we conclude that MMTV displays the most random dispersion of integration sites among retroviruses determined so far.
Topics: Animals; Cell Line, Tumor; Humans; Mammary Tumor Virus, Mouse; Mice; Molecular Sequence Data; Sequence Analysis, DNA; Virus Integration
PubMed: 18032509
DOI: 10.1128/JVI.02098-07 -
Proceedings of the National Academy of... May 2003
Review
Topics: DNA, Viral; Escherichia coli; Retroelements; Retroviridae; Selection, Genetic; Virus Integration
PubMed: 12732725
DOI: 10.1073/pnas.1031802100 -
Antiviral Research Apr 2020Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are members of the genus Roseolovirus in the Betaherpesvirinae subfamily. HHV-6B infects humans in the first years of life,... (Review)
Review
Human herpesvirus 6A (HHV-6A) and 6B (HHV-6B) are members of the genus Roseolovirus in the Betaherpesvirinae subfamily. HHV-6B infects humans in the first years of life, has a seroprevalence of more than 90% and causes Roseola Infantum, but less is known about HHV-6A. While most other herpesviruses maintain their latent genome as a circular episome, HHV-6A and HHV-6B (HHV-6A/B) have been shown to integrate their genome into the telomeres of infected cells. HHV-6A/B can also integrate into the chromosomes of germ cells, resulting in individuals carrying a copy of the virus genome in every nucleated cell of their bodies. This review highlights our current understanding of HHV-6A/B integration and reactivation as well as aspects that should be addressed in the future of this relatively young research area. It forms part of an online symposium on the prevention and therapy of DNA virus infections, dedicated to the memory of Mark Prichard.
Topics: Chromosomes; DNA, Viral; Genome, Viral; Herpesvirus 6, Human; Humans; Telomere; Virus Integration
PubMed: 32044155
DOI: 10.1016/j.antiviral.2020.104720 -
Molecular Biology Reports Apr 2010Trichosanthin (TCS) is a type I ribosome-inactivating protein with potent inhibitory activity against human immunodeficiency virus type 1. However, the anti-viral...
Trichosanthin (TCS) is a type I ribosome-inactivating protein with potent inhibitory activity against human immunodeficiency virus type 1. However, the anti-viral mechanism remains elusive. By a well-accepted HIV-1 integration assay, we demonstrated that TCS prevents HIV-1 DNA integration in a dose dependent manner in cell culture. At the same condition, TCS fails to induce obvious cytotoxicity and is also unable to interference viral early events such as viral entry, uncoating or reverse transcription. The HIV-1 integrase can integrate HIV-1 long-terminal repeats into cellular chromosome. The interaction of TCS with these viral integration components was also examined, indicating that TCS does not interact with HIV-1 integrase by the GST-pull down assay, but binds to the long terminal repeats in a transient manner. We further revealed that TCS can efficiently depurinate HIV-1 long-terminal repeats, which may be responsible for the inhibitory activity on HIV-1 integration. In conclusion, we elucidated that TCS specifically inhibits HIV-1 integration by depurinating the long-terminal repeats.
Topics: Cell Death; Cell Line; DNA Glycosylases; DNA, Viral; HIV-1; Humans; Purines; Terminal Repeat Sequences; Trichosanthin; Virus Integration
PubMed: 19669933
DOI: 10.1007/s11033-009-9668-2 -
International Review of Cell and... 2017The capacity of the human immunodeficiency virus (HIV-1) to establish latent infections constitutes a major barrier to the development of a cure for HIV-1. In latent... (Review)
Review
The capacity of the human immunodeficiency virus (HIV-1) to establish latent infections constitutes a major barrier to the development of a cure for HIV-1. In latent infection, replication competent HIV-1 provirus is integrated within the host genome but remains silent, masking the infected cells from the activity of the host immune response. Despite the progress in elucidating the molecular players that regulate HIV-1 gene expression, the mechanisms driving the establishment and maintenance of latency are still not fully understood. Transcription from the HIV-1 genome occurs in the context of chromatin and is subjected to the same regulatory mechanisms that drive cellular gene expression. Much like in eukaryotic genes, the nucleosomal landscape of the HIV-1 promoter and its position within genomic chromatin are determinants of its transcriptional activity. Understanding the multilayered chromatin-mediated mechanisms that underpin HIV-1 integration and expression is of utmost importance for the development of therapeutic strategies aimed at reducing the pool of latently infected cells. In this review, we discuss the impact of chromatin structure on viral integration, transcriptional regulation and latency, and the host factors that influence HIV-1 replication by regulating chromatin organization. Finally, we describe therapeutic strategies under development to target the chromatin-HIV-1 interplay.
Topics: Anti-HIV Agents; Chromatin; HIV-1; Humans; Transcription, Genetic; Virus Integration; Virus Latency
PubMed: 28069134
DOI: 10.1016/bs.ircmb.2016.08.006