HIV-1 replication complexes accumulate in nuclear speckles and integrate into speckle-associated genomic domains
Ashwanth C. Francis, Mariana Marin, Parmit K. Singh, Vasudevan Achuthan, M Prellberg, Kristina Palermino-Rowland, Shuiyun Lan, Philip R. Tedbury, Stefan G. Sarafianos, Alan Engelman, Gregory B. Melikyan
Abstract
Abstract The early steps of HIV-1 infection, such as uncoating, reverse transcription, nuclear import, and transport to integration sites are incompletely understood. Here, we imaged nuclear entry and transport of HIV-1 replication complexes in cell lines, primary monocyte-derived macrophages (MDMs) and CD4 + T cells. We show that viral replication complexes traffic to and accumulate within nuclear speckles and that these steps precede the completion of viral DNA synthesis. HIV-1 transport to nuclear speckles is dependent on the interaction of the capsid proteins with host cleavage and polyadenylation specificity factor 6 (CPSF6), which is also required to stabilize the association of the viral replication complexes with nuclear speckles. Importantly, integration site analyses reveal a strong preference for HIV-1 to integrate into speckle-associated genomic domains. Collectively, our results demonstrate that nuclear speckles provide an architectural basis for nuclear homing of HIV-1 replication complexes and subsequent integration into associated genomic loci.