scholarly journals Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis

2019 ◽  
Author(s):  
Jennifer Elliott ◽  
Jenna E. Eschbach ◽  
Pratibha C. Koneru ◽  
Wen Li ◽  
Maritza Puray Chavez ◽  
...  
Keyword(s):  
Rna Binding ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Class Ii ◽  
Viral Rna ◽  
Target Cells ◽  
Ribonucleoprotein Complexes ◽  
Virion Morphogenesis ◽  
Hiv 1

ABSTRACTA large number of HIV-1 integrase (IN) alterations, referred to as class II substitutions, exhibit pleotropic effects during virus replication. However, the underlying mechanism for the class II phenotype is not known. Here we demonstrate that all tested class II IN substitutions compromised IN-RNA binding in virions by one of three distinct mechanisms: i) markedly reducing IN levels thus precluding formation of IN complexes with viral RNA; ii) adversely affecting functional IN multimerization and consequently impairing IN binding to viral RNA; iii) directly compromising IN-RNA interactions without substantially affecting IN levels or functional IN multimerization. Inhibition of IN-RNA interactions resulted in mislocalization of the viral ribonucleoprotein complexes outside the capsid lattice, which led to premature degradation of the viral genome and IN in target cells. Collectively, our studies uncover causal mechanisms for the class II phenotype and highlight an essential role of IN-RNA interactions for accurate virion maturation.

scholarly journals Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jennifer L Elliott ◽  
Jenna E Eschbach ◽  
Pratibha C Koneru ◽  
Wen Li ◽  
Maritza Puray-Chavez ◽  
...  
Keyword(s):  
Rna Binding ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Class Ii ◽  
Viral Rna ◽  
Target Cells ◽  
Ribonucleoprotein Complexes ◽  
Immunodeficiency Virus ◽  
Hiv 1

A large number of human immunodeficiency virus 1 (HIV-1) integrase (IN) alterations, referred to as class II substitutions, exhibit pleiotropic effects during virus replication. However, the underlying mechanism for the class II phenotype is not known. Here we demonstrate that all tested class II IN substitutions compromised IN-RNA binding in virions by one of the three distinct mechanisms: (i) markedly reducing IN levels thus precluding the formation of IN complexes with viral RNA; (ii) adversely affecting functional IN multimerization and consequently impairing IN binding to viral RNA; and (iii) directly compromising IN-RNA interactions without substantially affecting IN levels or functional IN multimerization. Inhibition of IN-RNA interactions resulted in the mislocalization of viral ribonucleoprotein complexes outside the capsid lattice, which led to premature degradation of the viral genome and IN in target cells. Collectively, our studies uncover causal mechanisms for the class II phenotype and highlight an essential role of IN-RNA interactions for accurate virion maturation.

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

Viruses ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1005 ◽  
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.

scholarly journals Emergence of compensatory mutations reveal the importance of electrostatic interactions between HIV-1 integrase and genomic RNA

2021 ◽  
Author(s):  
Christian Shema Mugisha ◽  
Tung Dinh ◽  
Kasyap Tenneti ◽  
Jenna Eve Eschbach ◽  
Keanu Davis ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Rna Binding ◽  
Class Ii ◽  
Integrase Inhibitors ◽  
Ribonucleoprotein Complexes ◽  
Compensatory Mutations ◽  
Insight Into ◽  
Hiv 1 ◽  
Molecular Nature

Independent of its catalytic activity, HIV-1 integrase (IN) enzyme regulates proper particle maturation by binding to and packaging the viral RNA genome (gRNA) inside the mature capsid lattice. Allosteric integrase inhibitors (ALLINIs) and class II IN substitutions inhibit the binding of IN to the gRNA and cause the formation of non-infectious virions characterized by mislocalization of the viral ribonucleoprotein complexes between the translucent conical capsid lattice and the viral lipid envelope. To gain insight into the molecular nature of IN-gRNA interactions, we have isolated compensatory substitutions in the background of a class II IN (R269A/K273A) variant that directly inhibits IN binding to the gRNA. We found that additional D256N and D270N substitutions in the C-terminal domain (CTD) of IN restored its ability to bind gRNA and led to the formation of infectious particles with correctly matured morphology. Furthermore, reinstating the overall positive electrostatic potential of the CTD through individual D256R or D256K substitutions was sufficient to restore IN-RNA binding and infectivity for the R269A/K273A as well as the R262A/R263A class II IN mutants. The compensatory mutations did not impact functional IN oligomerization, suggesting that they directly contributed to IN binding to the gRNA. Interestingly, HIV-1 IN R269A/K273A, but not IN R262A/R263A, bearing compensatory mutations was more sensitive to ALLINIs providing key genetic evidence that specific IN residues required for RNA binding also influence ALLINI activity. Structural modeling provided further insight into the molecular nature of IN-gRNA interactions and ALLINI mechanism of action. Taken together, our findings highlight an essential role of IN-gRNA interactions for proper virion maturation and reveal the importance of electrostatic interactions between the IN CTD and the gRNA.

scholarly journals Allosteric HIV-1 Integrase Inhibitors Lead to Premature Degradation of the Viral RNA Genome and Integrase in Target Cells

2017 ◽  
Vol 91 (17) ◽  
Author(s):  
Michaela K. Madison ◽  
Dana Q. Lawson ◽  
Jennifer Elliott ◽  
Ayşe Naz Ozantürk ◽  
Pratibha C. Koneru ◽  
...  
Keyword(s):  
Reverse Transcriptase ◽  
Reverse Transcription ◽  
Hexagonal Lattice ◽  
Viral Rna ◽  
Productive Infection ◽  
Target Cells ◽  
Integrase Inhibitors ◽  
Ribonucleoprotein Complexes ◽  
Rna Genome ◽  
Hiv 1

ABSTRACT Recent evidence indicates that inhibition of HIV-1 integrase (IN) binding to the viral RNA genome by allosteric integrase inhibitors (ALLINIs) or through mutations within IN yields aberrant particles in which the viral ribonucleoprotein complexes (vRNPs) are eccentrically localized outside the capsid lattice. These particles are noninfectious and are blocked at an early reverse transcription stage in target cells. However, the basis of this reverse transcription defect is unknown. Here, we show that the viral RNA genome and IN from ALLINI-treated virions are prematurely degraded in target cells, whereas reverse transcriptase remains active and stably associated with the capsid lattice. The aberrantly shaped cores in ALLINI-treated particles can efficiently saturate and be degraded by a restricting TRIM5 protein, indicating that they are still composed of capsid proteins arranged in a hexagonal lattice. Notably, the fates of viral core components follow a similar pattern in cells infected with eccentric particles generated by mutations within IN that inhibit its binding to the viral RNA genome. We propose that IN-RNA interactions allow packaging of both the viral RNA genome and IN within the protective capsid lattice to ensure subsequent reverse transcription and productive infection in target cells. Conversely, disruption of these interactions by ALLINIs or mutations in IN leads to premature degradation of both the viral RNA genome and IN, as well as the spatial separation of reverse transcriptase from the viral genome during early steps of infection. IMPORTANCE Recent evidence indicates that HIV-1 integrase (IN) plays a key role during particle maturation by binding to the viral RNA genome. Inhibition of IN-RNA interactions yields aberrant particles with the viral ribonucleoprotein complexes (vRNPs) eccentrically localized outside the conical capsid lattice. Although these particles contain all of the components necessary for reverse transcription, they are blocked at an early reverse transcription stage in target cells. To explain the basis of this defect, we tracked the fates of multiple viral components in infected cells. Here, we show that the viral RNA genome and IN in eccentric particles are prematurely degraded, whereas reverse transcriptase remains active and stably associated within the capsid lattice. We propose that IN-RNA interactions ensure the packaging of both vRNPs and IN within the protective capsid cores to facilitate subsequent reverse transcription and productive infection in target cells.

scholarly journals Author response: Integrase-RNA interactions underscore the critical role of integrase in HIV-1 virion morphogenesis

2020 ◽  
Author(s):  
Jennifer L Elliott ◽  
Jenna E Eschbach ◽  
Pratibha C Koneru ◽  
Wen Li ◽  
Maritza Puray-Chavez ◽  
...  
Keyword(s):  
Critical Role ◽  
Author Response ◽  
Virion Morphogenesis ◽  
Hiv 1

scholarly journals Critical role of tristetraprolin and AU‐rich element RNA‐binding protein 1 in the suppression of cancer cell growth by globular adiponectin

FEBS Open Bio ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1964-1976 ◽  
Author(s):  
Nirmala Tilija Pun ◽  
Amrita Khakurel ◽  
Aastha Shrestha ◽  
Sang‐Hyun Kim ◽  
Pil‐Hoon Park
Keyword(s):  
Cell Growth ◽  
Cancer Cell ◽  
Rna Binding ◽  
Binding Protein ◽  
Critical Role ◽  
Rna Binding Protein ◽  
Cancer Cell Growth ◽  
Globular Adiponectin

scholarly journals OX40L/OX40 Signal Promotes IL-9 Production by Mucosal MAIT Cells During Helicobacter pylori Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Siqi Ming ◽  
Mei Zhang ◽  
Zibin Liang ◽  
Chunna Li ◽  
Jianzhong He ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Potential Role ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Mucosal Inflammation ◽  
Cross Linking ◽  
Mait Cells ◽  
H Pylori ◽  
Mait Cell

Mucosal associated invariant T (MAIT) cells play a critical role in Helicobacter pylori (H. pylori)-induced gastritis by promoting mucosal inflammation and aggravating mucosal injuries (1, 2). However, the underlying mechanism and key molecules involved are still uncertain. Here we identified OX40, a co-stimulatory molecule mainly expressed on T cells, as a critical regulator to promote proliferation and IL-9 production by MAIT cells and facilitate mucosal inflammation in H. pylori-positive gastritis patients. Serum examination revealed an increased level of IL-9 in gastritis patients. Meanwhile, OX40 expression was increased in mucosal MAIT cells, and its ligand OX40L was also up-regulated in mucosal dendritic cells (DCs) of gastritis patients, compared with healthy controls. Further results demonstrated that activation of the OX40/OX40L pathway promoted IL-9 production by MAIT cells, and MAIT cells displayed a highly-activated phenotype after the cross-linking of OX40 and OX40L. Moreover, the level of IL-9 produced by MAIT cells was positively correlated with inflammatory indexes in the gastric mucosa, suggesting the potential role of IL-9-producing MAIT cells in mucosal inflammation. Taken together, we elucidated that OX40/OX40L axis promoted mucosal MAIT cell proliferation and IL-9 production in H. pylori-induced gastritis, which may provide potential targeting strategies for gastritis treatment.

Indian study shows that encouraging knowledge sharing at work can help spark innovative behavior

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Keyword(s):  
Explicit Knowledge ◽  
Manufacturing Sector ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Innovative Behavior ◽  
Content Type ◽  
Indian Manufacturing Sector ◽  
Implicit And Explicit ◽  
The Relationship

Purpose The authors wanted to find out the most important mechanisms for encouraging innovative behavior in the Indian manufacturing sector. Design/methodology/approach The researchers collected data from Indian manufacturing organizations. They distributed questionnaires and received 288 complete ones. Items measured critical concepts. For OJ one example was “I have been fairly rewarded for the effort I put forth”. For KS, one sample was, “When I have learned something new, I tell my colleagues about it” and, “When they have learned something new, my colleagues tell me about it”. Meanwhile, IB was measured using items such as “I generate original solutions for problems”. Findings It highlighted the pivotal role of OJ in bolstering employees’ IB. When companies treat employees fairly, it encourages positive social interactions that lead to perceptions of supportiveness and trustworthiness. Employees reciprocate these sentiments with positive behavior. The study also showed the positive predictive influence of KS on IB. Finally, the results showed that the relationship between OJ and IB is complex, but KS is a pivotal mediator. Promotion of OJ, KS and IM is “vital” to spark innovation. Originality/value The authors felt their most important finding was to highlight the critical role of the underlying mechanism of KS, which is where individuals exchange implicit and explicit knowledge to create new knowledge. In addition, previous researchers have looked at the role of organizational justice in encouraging innovative behavior, but evidence from non-Western countries is scarce.

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

2020 ◽  
Vol 6 (38) ◽  
pp. eabb1328 ◽  
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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