A Sensitive Reporter Cell Line for HIV-1<i>tat</i>Activity, HIV-1 Inhibitors, and T Cell Activation Effects

Aguilar-Córdova, Estuardo; Chinen, Javier; Donehower, Larry A.; Lewis, Dorothy E.; Belmont, John W.

doi:10.1089/aid.1994.10.295

Cited by 128 publications

(108 citation statements)

References 15 publications

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“…This result clearly shows that CycK inhibits HIV-1 LTR-driven gene expression in the presence of Nef. To explore this finding further, we then used Jurkat-1G5 cells, a human CD4 ϩ reporter T-cell line having a copy of "integrated" LTR-Luc in the genome (43). Jurkat-1G5 cells were transfected with increasing amounts of CycK along with an HIV-1 molecular clone (pNL4-3) followed by a luciferase activity assay 48 h post-transfection.…”

Section: Resultsmentioning

confidence: 99%

Cyclin K Inhibits HIV-1 Gene Expression and Replication by Interfering with Cyclin-dependent Kinase 9 (CDK9)-Cyclin T1 Interaction in Nef-dependent Manner

Khan

Mitra

2011

Journal of Biological Chemistry

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Human immunodeficiency virus type-1 (HIV-1) perpetuates its survival in the host by utilizing multiple strategies such as irreversible integration of its DNA into the host cell genome to establish the provirus (1), diversification of its genome to escape or tolerate adaptive immune responses (2), and use of the accessory genes (nef, vif, vpu, and vpr) to modulate host cell immune responses further (3-5). These viral accessory genes are frequently seen as dispensable in many in vitro cell culture systems but seem to be indispensable, in the context of natural infections in vivo. Among these accessory genes, pleiotropic functions of Nef have been studied extensively. It is a 27-30-kDa, N-terminally myristoylated protein having a well characterized CD4 down-regulatory activity (6). Nef does not possess any enzymatic activity, but it modulates diverse signaling pathways and the gene expression of host cell proteins (7,8). Furthermore, Nef influences the activation state of the host cell by bringing together different host cell proteins, protein kinases, and components of the endocytic machinery and making the cells permissible to the virus (9, 10). All these functions of Nef are manifested by a number of events such as activation of signaling molecules, modulation of apoptosis, activation of transcription factors, mitigation of transcriptional repressors, and an increase in the infectivity of virions (11). Although these functions of Nef have been well studied, controversy exists on its role in viral infectivity and replication as both negative (12, 13) and positive (14, 15) roles have been attributed in the literature. Although a number of reports show that Nef increases viral replication by activating T-cells, the molecular basis of Nef-induced viral gene expression and replication remains to be clearly elucidated. Nef was also shown to physically interact with Tat and augment viral gene expression (16), although availability of Tat is critical for the elongation step of long terminal repeat (LTR) 2 -driven transcription by RNA polymerase II. Several cellular factors have been identified for their roles in this process, including positive transcription elongation factor b (P-TEFb) complex. Different P-TEFb complexes isolated from mammalian cells contain a common catalytic subunit, cyclin-dependent kinase 9 (CDK9), and one of the regulatory cyclins, CycT1, CycT2a, CycT2b,. However, CycT1-containing P-TEFb complex is the key complex responsible for HIV-1 transcription elongation (19). Tat is expressed early in the replicative cycle of HIV and is essential for viral gene expression from the LTR promoter. It recognizes the 5Ј-bulge in the transactivation response stem loop RNA, which is located at the 5Ј-end of all viral transcripts. Tat binds to CycT1, and together they form the combinatorial surface that interacts with the transactivation response RNA with high affinity and specificity. The obligate partner of CycT1, CDK9, then hyperphosphorylates the C-terminal domain (CTD) of RNA polymerase II, resulting in incre...

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Section: Resultsmentioning

confidence: 99%

Cyclin K Inhibits HIV-1 Gene Expression and Replication by Interfering with Cyclin-dependent Kinase 9 (CDK9)-Cyclin T1 Interaction in Nef-dependent Manner

Khan

Mitra

2011

Journal of Biological Chemistry

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“…Jurkat 1G5 cells contain a stably integrated HIV-1 LTR-luciferase reporter (52). At 18 h after treatment/infection, the cells were lysed, and promoter activity was determined using a luciferase assay kit (Promega).…”

Section: Methodsmentioning

confidence: 99%

Neisseria gonorrhoeae-derived heptose elicits an innate immune response and drives HIV-1 expression

Malott¹,

Keller

Gaudet³

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Clinical and epidemiological synergy exists between the globally important sexually transmitted infections, gonorrhea and HIV. Neisseria gonorrhoeae , which causes gonorrhea, is particularly adept at driving HIV-1 expression, but the molecular determinants of this relationship remain undefined. N. gonorrhoeae liberates a soluble factor that potently induces expression from the HIV-1 LTR in coinfected cluster of differentiation 4-positive (CD4 + ) T lymphocytes, but this factor is not a previously described innate effector. A genome-wide mutagenesis approach was undertaken to reveal which component(s) of N. gonorrhoeae induce HIV-1 expression in CD4 + T lymphocytes. A mutation in the ADP-heptose biosynthesis gene, hldA , rendered the bacteria unable to induce HIV-1 expression. The hldA mutant has a truncated lipooligosaccharide structure, contains lipid A in its outer membrane, and remains bioactive in a TLR4 reporter-based assay but did not induce HIV-1 expression. Mass spectrometry analysis of extensively fractionated N. gonorrhoeae- derived supernatants revealed that the LTR-inducing fraction contained a compound having a mass consistent with heptose-monophosphate (HMP). Heptose is a carbohydrate common in microbes but is absent from the mammalian glycome. Although ADP-heptose biosynthesis is common among Gram-negative bacteria, and heptose is a core component of most lipopolysaccharides, N. gonorrhoeae is peculiar in that it effectively liberates HMP during growth. This N. gonorrhoeae- derived HMP activates CD4 + T cells to invoke an NF-κB–dependent transcriptional response that drives HIV-1 expression and viral production. Our study thereby shows that heptose is a microbial-specific product that is sensed as an innate immune agonist and unveils the molecular link between N. gonorrhoeae and HIV-1.

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“…Cell Lines and Culture Conditions-The 1G5 T cell line, a Jurkat E6.1 derivative that harbors two stably integrated constructs constituted of the luciferase gene under the control of the HIV-1 SF2 LTR, was obtained from Dr. Estuardo Aguilar-Cordova and Dr. John Belmont through the AIDS Research and Reference Reagent Program (Division of AIDS, NIAID, National Institutes of Health, Bethesda, MD) (29). The human T lymphoid cell line Jurkat clone E6.1 was used in this study because it is considered as a model cell line for the study of T cell signaling machinery (30).…”

Section: Methodsmentioning

confidence: 99%

Attachment of Human Immunodeficiency Virus-1 (HIV-1) Particles Bearing Host-encoded B7-2 Proteins Leads to Nuclear Factor-κB- and Nuclear Factor of Activated T Cells-dependent Activation of HIV-1 Long Terminal Repeat Transcription

Bounou

Dumais

Tremblay

2001

Journal of Biological Chemistry

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A Sensitive Reporter Cell Line for HIV-1tatActivity, HIV-1 Inhibitors, and T Cell Activation Effects

Cited by 128 publications

References 15 publications

Cyclin K Inhibits HIV-1 Gene Expression and Replication by Interfering with Cyclin-dependent Kinase 9 (CDK9)-Cyclin T1 Interaction in Nef-dependent Manner

Cyclin K Inhibits HIV-1 Gene Expression and Replication by Interfering with Cyclin-dependent Kinase 9 (CDK9)-Cyclin T1 Interaction in Nef-dependent Manner

Neisseria gonorrhoeae-derived heptose elicits an innate immune response and drives HIV-1 expression

Attachment of Human Immunodeficiency Virus-1 (HIV-1) Particles Bearing Host-encoded B7-2 Proteins Leads to Nuclear Factor-κB- and Nuclear Factor of Activated T Cells-dependent Activation of HIV-1 Long Terminal Repeat Transcription

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