scholarly journals Molecular Characterization of Heterologous HIV-1gp120 Gene Expression Disruption inMycobacterium bovisBCG Host Strain: A Critical Issue for Engineering Mycobacterial Based-Vaccine Vectors

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Joan Joseph ◽  
Raquel Fernández-Lloris ◽  
Elías Pezzat ◽  
Narcís Saubi ◽  
Pere-Joan Cardona ◽  
...  
Keyword(s):  
Gene Expression ◽  
Critical Issue ◽  
Host Strain ◽  
Expression Vectors ◽  
Vaccine Vectors ◽  
E Coli ◽  
Hiv 1 ◽  
Complete Deletion ◽  
Genetic Rearrangements

Mycobacterium bovisBacillus Calmette-Guérin (BCG) as a live vector of recombinant bacterial vaccine is a promising system to be used. In this study, we evaluate the disrupted expression of heterologous HIV-1gp120 gene in BCG Pasteur host strain using replicative vectors pMV261 and pJH222. pJH222 carries a lysine complementing gene in BCG lysine auxotrophs. The HIV-1 gp120 gene expression was regulated by BCG hsp60 promoter (in plasmid pMV261) andMycobacteriaspp.α-antigen promoter (in plasmid pJH222). Among 14 rBCG:HIV-1gp120 (pMV261) colonies screened, 12 showed a partial deletion and two showed a complete deletion. However, deletion was not observed in all 10 rBCG:HIV-1gp120 (pJH222) colonies screened. In this study, we demonstrated thatE. coli/Mycobacterial expression vectors bearing a weak promoter and lysine complementing gene in a recombinant lysine auxotroph of BCG could prevent genetic rearrangements and disruption of HIV 1gp120 gene expression, a key issue for engineering Mycobacterial based vaccine vectors.

scholarly journals Tax induces the recruitment of NF-kB to unintegrated HIV-1 DNA to rescue viral gene expression and replication

2021 ◽  
Author(s):  
Ishak D. Irwan ◽  
Bryan R. Cullen
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Lentiviral Vectors ◽  
Expression Vectors ◽  
Viral Gene ◽  
Epigenetic Marks ◽  
Tax Protein ◽  
Human T Cell ◽  
Activation Of Transcription ◽  
Hiv 1

AbstractWe have previously reported that the normally essential step of integration of the HIV-1 proviral DNA intermediate into the host cell genome becomes dispensable in T cells that express the Human T cell leukemia virus 1 (HTLV-1) Tax protein. The rescue of integrase (IN) deficient HIV-1 replication by Tax results from the strong activation of transcription from the long terminal repeat (LTR) promoter on episomal HIV-1 DNA, an effect that is closely correlated with the recruitment of activating epigenetic marks, such as H3Ac, and depletion of repressive epigenetic marks, such as H3K9me3, from chromatinized unintegrated proviruses. In addition, activation of transcription from unintegrated HIV-1 DNA coincides with the recruitment of NF-kB to the two NF-kB binding sites found in the HIV-1 LTR enhancer. Here we report that the recruitment of NF-kB to unintegrated viral DNA precedes, and is a prerequisite for, Tax-induced changes in epigenetic marks, so that an IN-HIV-1 mutant lacking both LTR NF-kB sites is entirely non-responsive to Tax and fails to undergo the epigenetic changes listed above. We also report that heterologous promoters introduced into IN-HIV-1-based vectors are transcriptionally active even in the absence of Tax. Finally, we failed to reproduce a recent report arguing that heterologous promoters introduced into IN-vectors based on HIV-1 are more active if the HIV-1 promoter and enhancer, located in the LTR U3 region, are deleted, in a so-called self inactivating or SIN lentivector design.ImportanceIntegrase-deficient expression vectors based on HIV-1 are becoming increasingly popular as tools for gene therapy in vivo due to their inability to cause insertional mutagenesis. However, many IN-lentiviral vectors are able to achieve only low levels of gene expression and methods to increase this low level have not been extensively explored. Here we analyze how the HTLV-1 Tax protein is able to rescue the replication of IN-HIV-1 in T cells and describe IN-lentiviral vectors that are able to express a heterologous gene effectively.

Production and characterization of HIV-1 virus-like particles using transient gene expression in mammalian cells

2014 ◽  
Vol 31 ◽  
pp. S42
Author(s):  
Sonia Gutiérrez-Granados ◽  
Laura Cervera ◽  
Segura Maria de las Mercedes ◽  
Francesc Gòdia
Keyword(s):  
Gene Expression ◽  
Mammalian Cells ◽  
Transient Gene Expression ◽  
Virus Like Particles ◽  
Expression In Mammalian Cells ◽  
Hiv 1

scholarly journals Construction and Characterization of a Gradually Inducible Expression Vector for Halobacterium salinarum, Based on thekdpPromoter

2012 ◽  
Vol 78 (7) ◽  
pp. 2100-2105 ◽  
Author(s):  
Dorthe Kixmüller ◽  
Jörg-Christian Greie
Keyword(s):  
Gene Expression ◽  
Expression Vector ◽  
Expression System ◽  
Expression Patterns ◽  
Inducible Expression ◽  
Halobacterium Salinarum ◽  
Expression Vectors ◽  
Content Type ◽  
Inducible Expression System

ABSTRACTGradually inducible expression vectors which are governed by variations of growth conditions are powerful tools for gene expression of conditionally lethal mutants. Furthermore, controlled expression allows monitoring of overproduction of proteins at various stages in their expressing hosts. ForHalobacterium salinarum, which is often used as a paradigm for halophilic archaea, such an inducible expression system is not available to date. Here we show that thekdppromoter (Pkdp), which facilitates gene expression upon K+limitation, can be used to establish such a system for molecular applications. Pkdpfeatures a rather high expression rate, with an approximately 50-fold increase that can be easily varied by K+concentrations in the growth medium. Besides the construction of an expression vector, our work describes the characterization of expression patterns and, thus, offers a gradually inducible expression system to the scientific community.

Functional Pan-Universality of the Age-Related Regulatory Mechanisms of Gene Expression.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1943-1943
Author(s):  
Kotoku Kurachi ◽  
Jean-Marc Fontaine ◽  
Takahiro Abe ◽  
Sumiko Kurachi
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Critical Issue ◽  
Factor Ix ◽  
Expression Vectors ◽  
Gene Expressions ◽  
Cmv Promoter ◽  
Age Related ◽  
Time Period ◽  
Human Factor Ix

Abstract Through analyses of human factor IX (hFIX) and protein C (hPC) gene expressions in transgenic mice, we recently discovered the first molecular mechanism of age-dimension gene regulation, involving two critical genetic elements ASE and AIE required for age-related stable and increase patterns of gene expression, respectively. The next most critical issue to be tested was whether or not these elements, particularly ASE due to its possible utility, similarly functions with grossly different genes. We constructed hFIX expression vectors carrying a CMV promoter with or without ASE, and tested them in transgenic mice. Vectors with no ASE showed an age-dependent gradual decrease in hFIX expression, reaching the background levels in 3–9 months. Vectors with ASE, however, showed age-stable hFIX expression over the same time period. These findings supported the pan-universality of ASE function. As we previously reported, ASE regulates gene expression not only temporally but also spacially. With ASE, CMV-driven expression showed the highest in the heart muscle, whereas without ASE, the highest in the skeletal muscle. These results led to development of the Age Dimension Technology, a new field for exploring the unique applications of the age-related knowledge.

Characterization of an internally initiated integrase protein of HIV-1 produced in E. coli

1990 ◽  
Vol 170 (3) ◽  
pp. 1061-1066 ◽  
Author(s):  
Peter Zervos ◽  
Tom Hassell ◽  
Richard Van Frank ◽  
Mei T. Lai
Keyword(s):  
E Coli ◽  
Hiv 1 ◽  
Integrase Protein

scholarly journals Epigenetic Mechanisms of HIV-1 Persistence

Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 514
Author(s):  
Roxane Verdikt ◽  
Olivier Hernalsteens ◽  
Carine Van Lint
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Rational Design ◽  
Therapeutic Interventions ◽  
Regulatory Mechanisms ◽  
Viral Reservoir ◽  
Epigenetic Mechanisms ◽  
Latently Infected ◽  
Hiv 1

Eradicating HIV-1 in infected individuals will not be possible without addressing the persistence of the virus in its multiple reservoirs. In this context, the molecular characterization of HIV-1 persistence is key for the development of rationalized therapeutic interventions. HIV-1 gene expression relies on the redundant and cooperative recruitment of cellular epigenetic machineries to cis-regulatory proviral regions. Furthermore, the complex repertoire of HIV-1 repression mechanisms varies depending on the nature of the viral reservoir, although, so far, few studies have addressed the specific regulatory mechanisms of HIV-1 persistence in other reservoirs than the well-studied latently infected CD4+ T cells. Here, we present an exhaustive and updated picture of the heterochromatinization of the HIV-1 promoter in its different reservoirs. We highlight the complexity, heterogeneity and dynamics of the epigenetic mechanisms of HIV-1 persistence, while discussing the importance of further understanding HIV-1 gene regulation for the rational design of novel HIV-1 cure strategies.

scholarly journals Tax induces the recruitment of NF-kB to unintegrated HIV-1 DNA to rescue viral gene expression and replication

2021 ◽  
Author(s):  
Ishak D. Irwan ◽  
Bryan R. Cullen
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Viral Gene Expression ◽  
Lentiviral Vectors ◽  
Expression Vectors ◽  
Viral Gene ◽  
Epigenetic Marks ◽  
Tax Protein ◽  
Activation Of Transcription ◽  
Hiv 1

We have previously reported that the normally essential step of integration of the HIV-1 proviral DNA intermediate into the host cell genome becomes dispensable in T cells that express the Human T cell leukemia virus 1 (HTLV-1) Tax protein, a known activator of cellular NF-kB. The rescue of integrase (IN) deficient HIV-1 replication by Tax results from the strong activation of transcription from the long terminal repeat (LTR) promoter on episomal HIV-1 DNA, an effect that is closely correlated with the recruitment of activating epigenetic marks, such as H3Ac, and depletion of repressive epigenetic marks, such as H3K9me3, from chromatinized unintegrated proviruses. In addition, activation of transcription from unintegrated HIV-1 DNA coincides with the recruitment of NF-kB to the two NF-kB binding sites found in the HIV-1 LTR enhancer. Here we report that the recruitment of NF-kB to unintegrated viral DNA precedes, and is a prerequisite for, Tax-induced changes in epigenetic marks, so that an IN- HIV-1 mutant lacking both LTR NF-kB sites is entirely non-responsive to Tax and fails to undergo the epigenetic changes listed above. Interestingly, we found that induction of Tax expression at 24 hours post-infection, when unintegrated HIV-1 DNA is already fully repressed by inhibitory chromatin modifications, is able to effectively reverse the epigenetic silencing of that DNA and rescue viral gene expression. Finally, we report that heterologous promoters introduced into IN-deficient HIV-1-based vectors are transcriptionally active even in the absence of Tax and do not increase their activity when the HIV-1 promoter and enhancer, located in the LTR U3 region,are deleted, as has been recently proposed. Importance Integrase-deficient expression vectors based on HIV-1 are becoming increasingly popular as tools for gene therapy in vivo due to their inability to cause insertional mutagenesis. However, many IN- lentiviral vectors are able to achieve only low levels of gene expression and methods to increase this low level have not been extensively explored. Here we analyze how the HTLV-1 Tax protein is able to rescue the replication of IN- HIV-1 in T cells and describe IN- lentiviral vectors, lacking any inserted origin of replication, that are able to express a heterologous gene effectively.

Characterization of GPI2A, a Potent Inhibitor of HIV-1 Gene Expression and Viral Replication

1997 ◽  
Vol 16 (7-9) ◽  
pp. 1241-1249
Author(s):  
Michael I. Anazodo ◽  
Elena Duta ◽  
Horacio Salomon ◽  
Albert D. Friesen ◽  
Mark A. Wainberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Viral Replication ◽  
Potent Inhibitor ◽  
Hiv 1
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