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Tong, P. B. V.

Publications and source records attributed to Tong, P. B. V..

2 recordsLinked to original sources

A new HIV-1 latency reversing agent activating HIV-Tat

Despite its efficiency to prevent viral multiplication, antiretroviral therapy does not affect HIV-1 latently-infected cells. These cells do not produce significant amounts of viruses and constitute HIV-1 reservoir. To purge this long-lived viral reservoir, the "shock and kill" strategy relies on the use of latency reversing agents (LRAs) to induce activation of latent cells. All LRAs developed until now target cellular proteins and are therefore not specific for HIV-infected cells. Here we present a new LRA that binds and activates HIV-1 Tat which is the key regulator for viral transcription and latency reversal. This molecule termed D10 was designed to bind to the major groove of the Tat protein, and found to activate Tat transcriptional activity by stabilizing the HIV transcription complex. This LRA induces strong HIV production by latent cell lines and latent cells from people living with HIV-1. On latent cells from PBMCs, D10 is active at [~]50 nM, the concentration required to stabilize HIV transcription complex. D10 is the first Tat activator available and the first LRA that targets an HIV protein.

microbiology↗

A tripartite complex HIV-1 Tat-cyclophilin A-capsid protein enables Tat encapsidation that is required for HIV-1 infectivity

HIV-1 Tat is a key viral protein that stimulates several steps of viral gene expression. Tat is especially required for the transcription of viral genes but it is still not clear if and how Tat is incorporated into HIV-1 virions. Cyclophilin A (CypA) is a prolylisomerase that binds to HIV-1 capsid protein (CA) and is thereby encapsidated. Here we found that a Tat-CypA-CA tripartite complex assembles in HIV-1 infected cells. Biochemical and biophysical studies showed that high affinity interactions drive the assembly of this complex. Virions devoid of encapsidated Tat showed a 5-10 fold decrease in HIV-infectivity and, conversely, encapsidating Tat into {Delta}Tat viruses greatly enhanced infectivity. The absence of encapsidated Tat decreases the efficiency of retrotranscription by [~]50% and transcription by 99%. We thus identified a Tat-CypA-CA complex that enables Tat encapsidation and showed that encapsidated Tat is required to initiate robust HIV-1 infection and viral production.

microbiology↗