scholarly journals The HIV-1 capsid-binding host factor CPSF6 is post-transcriptionally regulated by the cellular microRNA miR-125b

2020 ◽  
Vol 295 (15) ◽  
pp. 5081-5094
Author(s):  
Evan Chaudhuri ◽  
Sabyasachi Dash ◽  
Muthukumar Balasubramaniam ◽  
Adrian Padron ◽  
Joseph Holland ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Mammalian Species ◽  
Cellular Protein ◽  
Luciferase Reporter ◽  
Down Regulation ◽  
Host Interaction ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Viral Dna Integration ◽  
Hiv 1

Cleavage and polyadenylation specificity factor 6 (CPSF6) is a cellular protein involved in mRNA processing. Emerging evidence suggests that CPSF6 also plays key roles in HIV-1 infection, specifically during nuclear import and integration targeting. However, the cellular and molecular mechanisms that regulate CPSF6 expression are largely unknown. In this study, we report a post-transcriptional mechanism that regulates CPSF6 via the cellular microRNA miR-125b. An in silico analysis revealed that the 3′UTR of CPSF6 contains a miR-125b–binding site that is conserved across several mammalian species. Because miRNAs repress protein expression, we tested the effects of miR-125b expression on CPSF6 levels in miR-125b knockdown and over-expression experiments, revealing that miR-125b and CPSF6 levels are inversely correlated. To determine whether miR-125b post-transcriptionally regulates CPSF6, we introduced the 3′UTR of CPSF6 mRNA into a luciferase reporter and found that miR-125b negatively regulates CPSF6 3′UTR-driven luciferase activity. Accordingly, mutations in the miR-125b seed sequence abrogated the regulatory effect of the miRNA on the CPSF6 3′UTR. Finally, pulldown experiments demonstrated that miR-125b physically interacts with CPSF6 3′UTR. Interestingly, HIV-1 infection down-regulated miR-125b expression concurrent with up-regulation of CPSF6. Notably, miR-125b down-regulation in infected cells was not due to reduced pri-miRNA or pre-miRNA levels. However, miR-125b down-regulation depended on HIV-1 reverse transcription but not viral DNA integration. These findings establish a post-transcriptional mechanism that controls CPSF6 expression and highlight a novel function of miR-125b during HIV-host interaction.

scholarly journals HIV-1 replication complexes accumulate in nuclear speckles and integrate into speckle-associated genomic domains

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ashwanth C. Francis ◽  
Mariana Marin ◽  
Parmit K. Singh ◽  
Vasudevan Achuthan ◽  
Mathew J. Prellberg ◽  
...  
Keyword(s):  
Viral Replication ◽  
Nuclear Import ◽  
Integration Site ◽  
Nuclear Speckles ◽  
Nuclear Entry ◽  
Primary Monocyte ◽  
Integration Sites ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

AbstractThe early steps of HIV-1 infection, such as uncoating, reverse transcription, nuclear import, and transport to integration sites are incompletely understood. Here, we imaged nuclear entry and transport of HIV-1 replication complexes in cell lines, primary monocyte-derived macrophages (MDMs) and CD4+ T cells. We show that viral replication complexes traffic to and accumulate within nuclear speckles and that these steps precede the completion of viral DNA synthesis. HIV-1 transport to nuclear speckles is dependent on the interaction of the capsid proteins with host cleavage and polyadenylation specificity factor 6 (CPSF6), which is also required to stabilize the association of the viral replication complexes with nuclear speckles. Importantly, integration site analyses reveal a strong preference for HIV-1 to integrate into speckle-associated genomic domains. Collectively, our results demonstrate that nuclear speckles provide an architectural basis for nuclear homing of HIV-1 replication complexes and subsequent integration into associated genomic loci.

scholarly journals HIV-1 uncoats in the nucleus near sites of integration

2020 ◽  
Vol 117 (10) ◽  
pp. 5486-5493 ◽  
Author(s):  
Ryan C. Burdick ◽  
Chenglei Li ◽  
MohamedHusen Munshi ◽  
Jonathan M. O. Rawson ◽  
Kunio Nagashima ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Nuclear Import ◽  
Host Protein ◽  
Productive Infection ◽  
Protein Cleavage ◽  
Integration Sites ◽  
Specificity Factor ◽  
Infected Cells ◽  
Viral Dna Integration ◽  
Hiv 1

HIV-1 capsid core disassembly (uncoating) must occur before integration of viral genomic DNA into the host chromosomes, yet remarkably, the timing and cellular location of uncoating is unknown. Previous studies have proposed that intact viral cores are too large to fit through nuclear pores and uncoating occurs in the cytoplasm in coordination with reverse transcription or at the nuclear envelope during nuclear import. The capsid protein (CA) content of the infectious viral cores is not well defined because methods for directly labeling and quantifying the CA in viral cores have been unavailable. In addition, it has been difficult to identify the infectious virions because only one of ∼50 virions in infected cells leads to productive infection. Here, we developed methods to analyze HIV-1 uncoating by direct labeling of CA with GFP and to identify infectious virions by tracking viral cores in living infected cells through viral DNA integration and proviral DNA transcription. Astonishingly, our results show that intact (or nearly intact) viral cores enter the nucleus through a mechanism involving interactions with host protein cleavage and polyadenylation specificity factor 6 (CPSF6), complete reverse transcription in the nucleus before uncoating, and uncoat <1.5 h before integration near (<1.5 μm) their genomic integration sites. These results fundamentally change our current understanding of HIV-1 postentry replication events including mechanisms of nuclear import, uncoating, reverse transcription, integration, and evasion of innate immunity.

scholarly journals TRIM5α restriction of HIV-1-N74D viruses in lymphocytes is caused by a loss of cyclophilin A protection

2020 ◽  
Author(s):  
Anastasia Selyutina ◽  
Lacy M. Simons ◽  
Angel Bulnes-Ramos ◽  
Judd F. Hultquist ◽  
Felipe Diaz-Griffero
Keyword(s):  
T Cells ◽  
Integration Site ◽  
Cyclophilin A ◽  
Site Preference ◽  
Primary Cells ◽  
Protein Cleavage ◽  
Wild Type ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

ABSTRACTThe core of HIV-1 viruses bearing the capsid change N74D (HIV-1-N74D) do not bind the human protein cleavage and polyadenylation specificity factor subunit 6 (CPSF6). In addition, HIV-1-N74D viruses have altered patterns of integration site preference in human cell lines. In primary human CD4+ T cells, HIV-1-N74D viruses exhibit infectivity defects when compared to wild type. The reason for this loss of infectivity in primary cells is unknown. We first investigated whether loss of CPSF6 binding accounts for the loss of infectivity. Depletion of CPSF6 in human CD4+ T cells did not affect the early stages of wild-type HIV-1 replication, suggesting that defective infectivity in the case of HIV-1-N74D is not due to the loss of CPSF6 binding. Based on our previous result that cyclophilin A (Cyp A) protected HIV-1 from human tripartite motif-containing protein 5α (TRIM5αhu) restriction in CD4+ T cells, we tested whether TRIM5αhu was involved in the decreased infectivity observed for HIV-1-N74D. Depletion of TRIM5αhu in CD4+ T cells rescued the infectivity of HIV-1-N74D, suggesting that HIV-1-N74D cores interacted with TRIM5αhu. Accordingly, TRIM5αhu binding to HIV-1-N74D cores was increased compared with that of wild-type cores, and consistently, HIV-1-N74D cores lost their ability to bind Cyp A. In conclusion, we showed that the decreased infectivity of HIV-1-N74D in CD4+ T cells is due to a loss of Cyp A protection from TRIM5αhu restriction activity.

scholarly journals Cleavage and Polyadenylation Specificity Factor 6 Is Required for Efficient HIV-1 Latency Reversal

mBio ◽  
2021 ◽  
Author(s):  
Yue Zheng ◽  
Heidi L. Schubert ◽  
Parmit K. Singh ◽  
Laura J. Martins ◽  
Alan N. Engelman ◽  
...  
Keyword(s):  
Life Cycle ◽  
Protein Phosphatase ◽  
Pol Ii ◽  
Phosphatase 2A ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Critical Residues ◽  
The Stability ◽  
Hiv 1

CPSF6 is a cellular factor that regulates cleavage and polyadenylation of mRNAs and participates in HIV-1 infection by facilitating targeting of preintegration complexes to the chromatin. Our observations reveal a second role of CPSF6 in the HIV-1 life cycle that involves regulation of viral transcription through controlling the stability of protein phosphatase 2A, which in turn regulates the phosphorylation/dephosphorylation status of critical residues in CDK9 and Pol II.

scholarly journals HIV-1 Capsid-Targeting Domain of Cleavage and Polyadenylation Specificity Factor 6

2012 ◽  
Vol 86 (7) ◽  
pp. 3851-3860 ◽  
Author(s):  
K. Lee ◽  
A. Mulky ◽  
W. Yuen ◽  
T. D. Martin ◽  
N. R. Meyerson ◽  
...  
Keyword(s):  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

scholarly journals Human Immunodeficiency Virus Type 1 Tat Increases the Expression of Cleavage and Polyadenylation Specificity Factor 73-Kilodalton Subunit Modulating Cellular and Viral Expression

2004 ◽  
Vol 78 (13) ◽  
pp. 6846-6854 ◽  
Author(s):  
Marco A. Calzado ◽  
Rocío Sancho ◽  
Eduardo Muñoz
Keyword(s):  
Gene Expression ◽  
Human Immunodeficiency Virus ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Tat Protein ◽  
Immunodeficiency Virus ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

ABSTRACT The human immunodeficiency virus type 1 (HIV-1) Tat protein, which is essential for HIV gene expression and viral replication, is known to mediate pleiotropic effects on various cell functions. For instance, Tat protein is able to regulate the rate of transcription of host cellular genes and to interact with the signaling machinery, leading to cellular dysfunction. To study the effect that HIV-1 Tat exerts on the host cell, we identified several genes that were up- or down-regulated in tat-expressing cell lines by using the differential display method. HIV-1 Tat specifically increases the expression of the cleavage and polyadenylation specificity factor (CPSF) 73-kDa subunit (CPSF3) without affecting the expression of the 160- and 100-kDa subunits of the CPSF complex. This complex comprises four subunits and has a key function in the 3′-end processing of pre-mRNAs by a coordinated interaction with other factors. CPSF3 overexpression experiments and knockdown of the endogenous CPSF3 by mRNA interference have shown that this subunit of the complex is an important regulatory protein for both viral and cellular gene expression. In addition to the known CPSF3 function in RNA polyadenylation, we also present evidence that this protein exerts transcriptional activities by repressing the mdm2 gene promoter. Thus, HIV-1-Tat up-regulation of CPSF3 could represent a novel mechanism by which this virus increases mRNA processing, causing an increase in both cell and viral gene expression.

scholarly journals Vpu Directs the Degradation of the Human Immunodeficiency Virus Restriction Factor BST-2/Tetherin via a βTrCP-Dependent Mechanism

2009 ◽  
Vol 83 (16) ◽  
pp. 7931-7947 ◽  
Author(s):  
Janet L. Douglas ◽  
Kasinath Viswanathan ◽  
Matthew N. McCarroll ◽  
Jean K. Gustin ◽  
Klaus Früh ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Molecular Mechanisms ◽  
Cellular Protein ◽  
Dependent Manner ◽  
Wild Type ◽  
Concanamycin A ◽  
Virion Release ◽  
Early Endosomes ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The primary roles attributed to the human immunodeficiency virus type 1 (HIV-1) Vpu protein are the degradation of the viral receptor CD4 and the enhancement of virion release. With regard to CD4 downregulation, Vpu has been shown to act as an adapter linking CD4 with the ubiquitin-proteasome machinery via interaction with the F-box protein βTrCP. To identify additional cellular βTrCP-dependent Vpu targets, we performed quantitative proteomics analyses using the plasma membrane fraction of HeLa cells expressing either wild-type Vpu or a Vpu mutant (S52N/S56N) that does not bind βTrCP. One cellular protein, BST-2 (CD317), was consistently underrepresented in the membrane proteome of cells expressing wild-type Vpu compared to the proteome of cells expressing the Vpu mutant. To verify the biological relevance of this phenotype for HIV pathogenesis, we showed that in T cells infected with HIV-1, BST-2 downregulation occurred in a Vpu-dependent manner. Recently, BST-2 has been identified as the interferon-inducible cellular factor Tetherin, which restricts HIV virion release in the absence of Vpu. We address here the unresolved mechanism of Vpu-mediated BST-2 downregulation. Our data show that the presence of wild-type Vpu reduced cell surface and total steady-state BST-2 levels, whereas that of the mutant Vpu had no effect. In addition, treatment of cells with the lysosome acidification inhibitor concanamycin A, but not treatment with the proteasome inhibitor MG132, reduced BST-2 downregulation by wild-type Vpu, thereby suggesting that the presence of Vpu leads to the degradation of BST-2 via an endosome-lysosome degradation pathway. The importance of βTrCP in this process was confirmed by demonstrating that in the absence of βTrCP, BST-2 levels were restored despite the presence of Vpu. Taken together, these data support the hypothesis that, in similarity to its role in CD4 degradation, Vpu acts as an adapter molecule linking BST-2 to the cellular ubiquitination machinery via βTrCP. However, in contrast to the proteasome-dependent degradation of CD4, which occurs in the endoplasmic reticulum, Vpu appears to interact with BST-2 in the trans-Golgi network or in early endosomes, leading to lysosomal degradation of BST-2. Via this action, Vpu could counter the tethering function of BST-2, resulting in enhanced HIV-1 virion release. Interestingly, although HIV-2 does not express Vpu, an isolate known to exhibit enhanced viral egress can downregulate surface BST-2 by an as-yet-unknown mechanism that does not appear to involve degradation. Understanding the molecular mechanisms of both Vpu-dependent and -independent mediated antagonism of BST-2 will be critical for therapeutic strategies that exploit this novel viral function.

scholarly journals Cytoplasmic CPSF6 Regulates HIV-1 Capsid Trafficking and Infection in a Cyclophilin A-Dependent Manner

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Zhou Zhong ◽  
Jiying Ning ◽  
Emerson A. Boggs ◽  
Sooin Jang ◽  
Callen Wallace ◽  
...  
Keyword(s):  
T Cells ◽  
Cell Nucleus ◽  
Viral Genome ◽  
Cyclophilin A ◽  
Higher Order ◽  
Human Protein ◽  
Dependent Manner ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) capsid binds host proteins during infection, including cleavage and polyadenylation specificity factor 6 (CPSF6) and cyclophilin A (CypA). We observe that HIV-1 infection induces higher-order CPSF6 formation, and capsid-CPSF6 complexes cotraffic on microtubules. CPSF6-capsid complex trafficking is impacted by capsid alterations that reduce CPSF6 binding or by excess cytoplasmic CPSF6 expression, both of which are associated with decreased HIV-1 infection. Higher-order CPSF6 complexes bind and disrupt HIV-1 capsid assemblies in vitro. Disruption of HIV-1 capsid binding to CypA leads to increased CPSF6 binding and altered capsid trafficking, resulting in reduced infectivity. Our data reveal an interplay between CPSF6 and CypA that is important for cytoplasmic capsid trafficking and HIV-1 infection. We propose that CypA prevents HIV-1 capsid from prematurely engaging cytoplasmic CPSF6 and that differences in CypA cellular localization and innate immunity may explain variations in HIV-1 capsid trafficking and uncoating in CD4+ T cells and macrophages. IMPORTANCE HIV is the causative agent of AIDS, which has no cure. The protein shell that encases the viral genome, the capsid, is critical for HIV replication in cells at multiple steps. HIV capsid has been shown to interact with multiple cell proteins during movement to the cell nucleus in a poorly understood process that may differ during infection of different cell types. In this study, we show that premature or too much binding of one human protein, cleavage and polyadenylation specificity factor 6 (CPSF6), disrupts the ability of the capsid to deliver the viral genome to the cell nucleus. Another human protein, cyclophilin A (CypA), can shield HIV capsid from premature binding to CPSF6, which can differ in CD4+ T cells and macrophages. Better understanding of how HIV infects cells will allow better drugs to prevent or inhibit infection and pathogenesis.

scholarly journals Cytoplasmic CPSF6 regulates HIV-1 capsid trafficking and infection in a cyclophilin A-dependent manner

2020 ◽  
Author(s):  
Zhou Zhong ◽  
Jiying Ning ◽  
Emerson A. Boggs ◽  
Sooin Jang ◽  
Callen Wallace ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Cyclophilin A ◽  
Higher Order ◽  
Dependent Manner ◽  
Host Proteins ◽  
Immunodeficiency Virus ◽  
Cleavage And Polyadenylation ◽  
Specificity Factor ◽  
Hiv 1

SummaryHuman immunodeficiency virus type 1 (HIV-1) capsid binds host proteins during infection, including cleavage and polyadenylation specificity factor 6 (CPSF6) and cyclophilin A (CypA). We observe that HIV-1 infection induces higher-order CPSF6 formation and capsid-CPSF6 complexes co-traffic on microtubules. CPSF6-capsid complex trafficking is impacted by capsid alterations that reduce CPSF6 binding or by excess cytoplasmic CPSF6 expression, both of which are associated with decreased HIV-1 infection. Higher-order CPSF6 complexes bind and disrupt HIV-1 capsid assemblies in vitro. Disruption of HIV-1 capsid binding to CypA leads to increased CPSF6 binding and altered capsid trafficking, resulting in reduced infectivity. Our data reveal an interplay between CPSF6 and CypA that is important for cytoplasmic capsid trafficking and HIV-1 infection. We propose that CypA prevents HIV-1 capsid from prematurely engaging cytoplasmic CPSF6 and that differences in CypA cellular localization and innate immunity may explain cell-specific variations in HIV-1 capsid trafficking and uncoating.Graphical Abstract

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