Advanced Molecular Virology

Upon infection, HIV-1 can either replicate and acutely infect cells or remain dormant. Currently, we have no means of eradicating the latent virus from cells. The establishment of viral persistence could be an early event, probably linked to the active transport of the PIC through the NPC. The NPC is one of the major actors in the early steps of HIV-1 infection. Notably, Nups have pleiotropic roles, in fact they interact with different protein complexes involved in gene transcription, chromatin remodelling, DNA repair, and DNA replication. Past and current studies from our group highlighted the importance of the interplay between individual nucleoporins and the viral capsid for HIV-1 nuclear entry and for an efficient viral integration. Ultrastructural studies revealed that the viral core remodels to cross the nuclear pore complex. On the other hand, the HIV-1 retrotranscribed DNA has never been visualized in live, hampering studies on the spatiotemporal dynamics linked to viral silencing or activation. In fact, the direct detection of HIV-1 genomes after reverse transcription has been a technological challenge to study HIV-1 PIC morphogenesis, as well as viral integration sites distribution. We recently set up in our lab a new appealing versatile fluorescence system, called HIV-1 ANCHOR, to overcome the aforementioned limitations to study the host environment (chromatin and nuclear factors) surrounding nuclear viral forms that can dictate viral transcription or silencing. We generated a HIV-1 WT that can be labeled for both viral DNA and viral RNA in live. This system can be used in primary lymphocytes or macrophages allowing to perform studies on the main target cells of HIV-1. Our new tool will allow to follow the fate of HIV-1 in the natural target cells.

Results from our group indicate that HIV-1 creates nuclear microenvironments to replicate. Post-nuclear entry studies showed the existence of a nuclear reverse transcription (RT), revising the RT “dogma”. This viral step occurs in HIV-1-induced-membraneless organelles. Our future studies will shed light on this intriguing phenomenon to unravel underlying molecular mechanisms (in vitro) and to evaluate their role in HIV reservoirs (in vivo).