UHRF1 Suppresses HIV-1 Transcription and Promotes HIV-1 Latency by Competing with p-TEFb for Ubiquitination-Proteasomal Degradation of Tat

HIV-1 latency is systematically modulated by host factors and viral proteins. In our work, we identified a critical role of host factor ubiquitin-like with PHD and RING finger domain 1 (UHRF1) in HIV-1 latency via the modulation of the viral protein Tat stability.

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The balance between p53 isoforms modulates the efficiency of HIV-1 infection in macrophages

Journal of Virology ◽

10.1128/jvi.01188-21 ◽

2021 ◽

Author(s):

Yann Breton ◽

Corinne Barat ◽

Michel J. Tremblay

Keyword(s):

Virus Replication ◽

Potential Role ◽

Host Factors ◽

Fine Tuning ◽

Mrna Levels ◽

Cellular Environment ◽

P53 Isoforms ◽

Antiviral Role ◽

Hiv 1

Several host factors influence HIV-1 infection and replication. The p53-mediated antiviral role in monocytes-derived macrophages (MDMs) was previously highlighted. Indeed, an increase in p53 level results in a stronger restriction against HIV-1 early replication steps through SAMHD1 activity. In this study, we investigated the potential role of some p53 isoforms in HIV-1 infection. Transfection of isoform-specific siRNA induces distinctive effects on the virus life cycle. For example, in contrast to a siRNA targeting all isoforms, a knockdown of Δ133p53 transcripts reduces virus replication in MDMs that is correlated with a decrease in phosphorylated inactive SAMHD1. Combination of Δ133p53 knockdown and Nutlin-3, a pharmacological inhibitor of MDM2 that stabilizes p53, further reduces susceptibility of MDMs to HIV-1 infection, thus suggesting an inhibitory role of Δ133p53 towards p53 antiviral activity. In contrast, p53β knockdown in MDMs increases the viral production independently of SAMHD1. Moreover, experiments with a Nef-deficient virus show that this viral protein plays a protective role against the antiviral environment mediated by p53. Finally, HIV-1 infection affects the expression pattern of p53 isoforms by increasing p53β and p53γ mRNA levels while stabilizing the protein level of p53α and some isoforms from the p53β subclass. The balance between the various p53 isoforms is therefore an important factor in the overall susceptibility of macrophages to HIV-1 infection, fine-tuning the p53 response against HIV-1. This study brings a new understanding of the complex role of p53 in virus replication processes in myeloid cells. Importance As of today, HIV-1 is still considered as a global pandemic without a functional cure, partly because of the presence of stable viral reservoirs. Macrophages constitute one of these cell reservoirs, contributing to the viral persistence. Studies investigating the host factors involved in cell susceptibility to HIV-1 infection might lead to a better understanding of the reservoir formation and will eventually allow the development of an efficient cure. Our team previously showed the antiviral role of p53 in macrophages, which acts by compromising the early steps of HIV-1 replication. In this study, we demonstrate the involvement of p53 isoforms, which regulates p53 activity and define the cellular environment influencing viral replication. In addition, the results concerning the potential role of p53 in antiviral innate immunity could be transposed to other fields of virology and suggest that knowledge in oncology can be applied to HIV-1 research.

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Going beyond Integration: The Emerging Role of HIV-1 Integrase in Virion Morphogenesis

Viruses ◽

10.3390/v12091005 ◽

2020 ◽

Vol 12 (9) ◽

pp. 1005 ◽

Cited By ~ 2

Author(s):

Jennifer L. Elliott ◽

Sebla B. Kutluay

Keyword(s):

Life Cycle ◽

Viral Genome ◽

Critical Role ◽

Viral Rna ◽

Target Cells ◽

Host Chromosome ◽

Virion Morphogenesis ◽

Rna Genome ◽

Hiv 1

The HIV-1 integrase enzyme (IN) plays a critical role in the viral life cycle by integrating the reverse-transcribed viral DNA into the host chromosome. This function of IN has been well studied, and the knowledge gained has informed the design of small molecule inhibitors that now form key components of antiretroviral therapy regimens. Recent discoveries unveiled that IN has an under-studied yet equally vital second function in human immunodeficiency virus type 1 (HIV-1) replication. This involves IN binding to the viral RNA genome in virions, which is necessary for proper virion maturation and morphogenesis. Inhibition of IN binding to the viral RNA genome results in mislocalization of the viral genome inside the virus particle, and its premature exposure and degradation in target cells. The roles of IN in integration and virion morphogenesis share a number of common elements, including interaction with viral nucleic acids and assembly of higher-order IN multimers. Herein we describe these two functions of IN within the context of the HIV-1 life cycle, how IN binding to the viral genome is coordinated by the major structural protein, Gag, and discuss the value of targeting the second role of IN in virion morphogenesis.

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A VH1-69 antibody lineage from an infected Chinese donor potently neutralizes HIV-1 by targeting the V3 glycan supersite

Science Advances ◽

10.1126/sciadv.abb1328 ◽

2020 ◽

Vol 6 (38) ◽

pp. eabb1328 ◽

Cited By ~ 1

Author(s):

Sonu Kumar ◽

Bin Ju ◽

Benjamin Shapero ◽

Xiaohe Lin ◽

Li Ren ◽

...

Keyword(s):

Cell Sorting ◽

Neutralizing Antibodies ◽

Critical Role ◽

Viral Escape ◽

Germline Gene ◽

Broadly Neutralizing Antibodies ◽

Functional Studies ◽

Single Genome ◽

Hiv 1

An oligomannose patch around the V3 base of HIV-1 envelope glycoprotein (Env) is recognized by multiple classes of broadly neutralizing antibodies (bNAbs). Here, we investigated the bNAb response to the V3 glycan supersite in an HIV-1–infected Chinese donor by Env-specific single B cell sorting, structural and functional studies, and longitudinal analysis of antibody and virus repertoires. Monoclonal antibodies 438-B11 and 438-D5 were isolated that potently neutralize HIV-1 with moderate breadth, are encoded by the VH1-69 germline gene, and have a disulfide-linked long HCDR3 loop. Crystal structures of Env-bound and unbound antibodies revealed heavy chain–mediated recognition of the glycan supersite with a unique angle of approach and a critical role of the intra-HCDR3 disulfide. The mechanism of viral escape was examined via single-genome amplification/sequencing and glycan mutations around the N332 supersite. Our findings further emphasize the V3 glycan supersite as a prominent target for Env-based vaccine design.

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The critical role of human transcriptional repressor CTCF mRNA up-regulation in the induction of anti-HIV-1 responses in CD4+ T cells

Immunology Letters ◽

10.1016/j.imlet.2007.11.017 ◽

2008 ◽

Vol 117 (1) ◽

pp. 35-44 ◽

Cited By ~ 6

Author(s):

Yuchang Li ◽

Guanhua Li ◽

Anna Ivanova ◽

Sagiv Aaron ◽

Malgorzata Simm

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Critical Role ◽

Transcriptional Repressor ◽

Anti Hiv ◽

Hiv 1

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Critical role of PP2A-B56 family protein degradation in HIV-1 Vif mediated G2 cell cycle arrest

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2020.04.123 ◽

2020 ◽

Vol 527 (1) ◽

pp. 257-263

Author(s):

Kayoko Nagata ◽

Keisuke Shindo ◽

Yusuke Matsui ◽

Kotaro Shirakawa ◽

Akifumi Takaori-Kondo

Keyword(s):

Cell Cycle ◽

Protein Degradation ◽

Cell Cycle Arrest ◽

Critical Role ◽

Cycle Arrest ◽

Family Protein ◽

G2 Cell Cycle Arrest ◽

Hiv 1

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The mechanism by which molecules containing the HIV gp41 core-binding motif HXXNPF inhibit HIV-1 envelope glycoprotein-mediated syncytium formation

Biochemical Journal ◽

10.1042/bj20061275 ◽

2007 ◽

Vol 403 (3) ◽

pp. 565-571 ◽

Cited By ~ 15

Author(s):

Jing-He Huang ◽

Heng-Wen Yang ◽

Shuwen Liu ◽

Jing Li ◽

Shibo Jiang ◽

...

Keyword(s):

Envelope Glycoprotein ◽

Critical Role ◽

Syncytium Formation ◽

Phage Clone ◽

Fusion Process ◽

Binding Motif ◽

Active Core ◽

Different Temperatures ◽

Hiv 1

The HIV-1 gp41 (glycoprotein 41) core plays a critical role in fusion between the viral and target cell membranes. We previously identified a gp41 core-binding motif, HXXNPF, by screening the phage display peptide libraries. In the present study, we elucidated the mechanism of action of HXXNPF motif-containing molecules of different sizes, including the phage clone L7.8 (a selected positive phage clone), L7.8-g3p* (a 10–kDa fragment of the gene 3 protein) and JCH-4 (a peptide containing 13 residues of L7.8-g3p*), regarding their respective binding abilities to the six-helix bundle and inhibition on syncytium formation at different temperatures. We found that all of the HXXNPF motif-containing molecules could bind to the gp41 core, and that their binding sites may be located in the N-helix domain. L7.8-g3p* and JCH-4 effectively inhibited HIV-1 Env (envelope glycoprotein)-mediated syncytium formation at 37 °C, while the phage clone L7.8 showed no inhibition under the same conditions. However, at suboptimal temperature (31.5 °C), all of these HXXNPF motif-containing molecules were capable of inhibiting syncytium formation. These results suggest that these HXXNPF motif-containing molecules mainly bind to the gp41 core and stop the fusion process mediated by the fusion-active core, resulting in inhibition of HIV-1 fusion and entry. The HXXNPF motif-containing molecules may be used as probes for studying the role of the HIV-1 gp41 core in the late stage of the membrane-fusion process.

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Critical Role of Helix 4 of HIV-1 Capsid C-terminal Domain in Interactions with Human Lysyl-tRNA Synthetase

Journal of Biological Chemistry ◽

10.1074/jbc.m706256200 ◽

2007 ◽

Vol 282 (44) ◽

pp. 32274-32279 ◽

Cited By ~ 27

Author(s):

Brandie J. Kovaleski ◽

Robert Kennedy ◽

Ahmad Khorchid ◽

Lawrence Kleiman ◽

Hiroshi Matsuo ◽

...

Keyword(s):

Critical Role ◽

Trna Synthetase ◽

Terminal Domain ◽

Hiv 1

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Molecular Mechanism of SARS-CoVs Orf6 Targeting the Rae1–Nup98 Complex to Compete With mRNA Nuclear Export

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.813248 ◽

2022 ◽

Vol 8 ◽

Author(s):

Tinghan Li ◽

Yibo Wen ◽

Hangtian Guo ◽

Tingting Yang ◽

Haitao Yang ◽

...

Keyword(s):

Nuclear Export ◽

Rna Binding ◽

Critical Role ◽

Tight Binding ◽

Viral Proteins ◽

Interferon Signaling ◽

Binding Groove ◽

Mrna Binding ◽

Common Target

The accessory protein Orf6 is uniquely expressed in sarbecoviruses including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which is an ongoing pandemic. SARS-CoV-2 Orf6 antagonizes host interferon signaling by inhibition of mRNA nuclear export through its interactions with the ribonucleic acid export 1 (Rae1)–nucleoporin 98 (Nup98) complex. Here, we confirmed the direct tight binding of Orf6 to the Rae1-Nup98 complex, which competitively inhibits RNA binding. We determined the crystal structures of both SARS-CoV-2 and SARS-CoV-1 Orf6 C-termini in complex with the Rae1–Nup98 heterodimer. In each structure, SARS-CoV Orf6 occupies the same potential mRNA-binding groove of the Rae1–Nup98 complex, comparable to the previously reported structures of other viral proteins complexed with Rae1-Nup98, indicating that the Rae1–Nup98 complex is a common target for different viruses to impair the nuclear export pathway. Structural analysis and biochemical studies highlight the critical role of the highly conserved methionine (M58) of SARS-CoVs Orf6. Altogether our data unravel a mechanistic understanding of SARS-CoVs Orf6 targeting the mRNA-binding site of the Rae1–Nup98 complex to compete with the nuclear export of host mRNA, which further emphasizes that Orf6 is a critical virulence factor of SARS-CoVs.

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S2 from Equine infectious anemia virus is an infectivity factor which counteracts the retroviral inhibitors SERINC5 and SERINC3

10.1101/065078 ◽

2016 ◽

Author(s):

Ajit Chande ◽

Cristiana Cuccurullo ◽

Annachiara Rosa ◽

Serena Ziglio ◽

Susan Carpenter ◽

...

Keyword(s):

Equine Infectious Anemia Virus ◽

Critical Role ◽

Host Factor ◽

Target Cells ◽

Accessory Protein ◽

Post Translational Modification ◽

Virus Particles ◽

Equine Infectious Anemia ◽

Anemia Virus ◽

Hiv 1

ABSTRACTThe lentivirus equine infectious anemia virus (EIAV) encodes S2, a pathogenic determinant important for virus replication and disease progression in horses. No molecular function has yet been linked to this accessory protein. We now report that S2 can replace the activity of Nef on HIV-1 infectivity, being required to antagonize the inhibitory activity of SERINC proteins on Nef-defective HIV-1. Similar to Nef, S2 excludes SERINC5 from virus particles and requires an ExxxLL motif predicted to recruit the clathrin adaptor AP2. Accordingly, a functional endocytic machinery is essential for S2-mediated infectivity enhancement, which is impaired by inhibitors of clathrin-mediated endocytosis. In addition to retargeting SERINC5 to a late endosomal compartment, S2 promotes the host factor degradation. Emphasizing the similarity with Nef, we show that S2 is myristoylated and, compatible with a crucial role of the post-translational modification, its N-terminal glycine is required for the anti-SERINC5 activity.EIAV-derived vectors devoid of S2 are less susceptible than HIV-1 to the inhibitory effect of both human and equine SERINC5. We then identified the envelope glycoprotein of EIAV as a determinant which also modulates retrovirus susceptibility to SERINC5, indicating a bi-modular ability of the equine lentivirus to counteract the host factor.S2 shares no sequence homology with other retroviral factors known to counteract SERINC5. Adding to primate lentivirus Nef and gammaretrovirus glycoGag, the accessory protein from EIAV makes another example of a retroviral virulence determinant which independently evolved SERINC5-antagonizing activity. SERINC5 therefore plays a critical role for the interaction of the host with diverse retrovirus pathogens.Significance StatementSERINC5 and SERINC3 are recently discovered cellular inhibitors of retroviruses, which are incorporated into virus particles and impair their ability to propagate the infection to target cells. Only two groups of viruses (represented by HIV-1 and MLV) have so far been identified to have evolved the ability of counteracting SERINC inhibition. We now discovered that Equine infectious anemia virus, which causes a debilitating disease in horses, also acquired the ability to protect the virus particle from inhibition by SERINC5 and SERINC3, using its small protein S2. The evidence that three different retroviruses have independently evolved the ability to elude inhibition bySERINC5 and SERINC3 indicates that these cellular factors play a fundamental role against various retrovirus pathogens.

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Determinating the role of the E3 Ubiquitin Ligase Ariadne 2 in mammalian systemss

Clinical & Investigative Medicine ◽

10.25011/cim.v30i4.2863 ◽

2007 ◽

Vol 30 (4) ◽

pp. 87

Author(s):

A. E. Lin ◽

A. Wakeham ◽

A. You-Ten ◽

G. Wood ◽

T. W. Mak

Keyword(s):

Function Analysis ◽

Critical Role ◽

Ring Finger ◽

E3 Ligase ◽

Signalling Pathways ◽

Loss Of Function ◽

In Vivo Models

Ubiquitination is a eukaryotic process of selective proteolysis, where a highly conserved ubiquitin protein is selectively added as a chain to the targeted to a protein for degradation. In recent years, the process of ubiquitination has been shown to be a critical mechanism that can affect essential signalling pathways, including apoptosis, cell cycle arrest and induction of the inflammatory response. Thus, alterations in the ubiquitination process can alter signalling pathways pivotal to numerous disease pathologies. This is clearly demonstrated in perturbations of ubiquitination in the NFκB giving rise to cancer and other immunological disease processes. To gain insight into pathways that require regulation by ubiquitination, our lab has directed focus on the highly conserved E3 ligase, Ariadne 2. Ariadne 2 is characterized as a putative RING finger E3 ligase and is part of the family of highly conserved RBR (RING-B-Box-RING) superfamily. The role of Ariadne 2 has been well studied in Drosophila melanogaster, however, little is known of the function of Ariadne 2 in mammalian systems. Therefore, the main objectives of the project are as follows: To determine the biological role of Ariadne 2, the role of Ariadne 2 in development and differentiation, and the consequences of in vivo loss of Ariadne 2 expression. We are currently investigating the role of Ariadne 2 as an E3 ligase and its involvement in the immune response. To date, we have shown that Ariadne 2 is ubiquitously expressed, especially in the brain, heart, spleen and thymus. For in vivo loss of function analysis, mice were generated by homologous recombination to be deficient for Ariadne 2. These deficient mice die prematurely soon after birth, suggesting a critical role for Ariadne 2 in development and survival. We are currently focusing on the role of Ariadne 2 in development and it’s role in immune pathologies, in particular, spontaneous autoimmunity, using both in vitro studies and in vivo models.

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