# HIV-1 Preintegration Trafficking and Nuclear Localization

> **NIH NIH R01** · DANA-FARBER CANCER INST · 2024 · $612,217

## Abstract

PROJECT SUMMARY
This longstanding NIH grant over its lifetime has made seminal discoveries on the mechanisms of intranuclear
HIV-1 trafficking and nuclear localization. In prior funding cycles, we determined that the nuclear pore complex
protein nucleoporin 153 interacted with the viral protein capsid to affect the translocation of incoming viral
replication complexes into the cell nucleus and sites of viral DNA integration in the human genome. We also
first identified the cellular alternate polyadenylation protein cleavage and polyadenylation specificity factor 6
(CPSF6) as a direct binding partner of the viral capsid and revealed an important role for this interaction in
integration of the viral reverse transcript into active chromatin. Over the most recent funding cycle, our work
has clarified that the capsid-CPSF6 interaction is critical for viral replication complexes to travel into the nuclear
structure, where they colocalize with nuclear organelle structures that are known as nuclear speckles. Using
novel bioinformatic tools, our work moreover revealed the significant preference for HIV-1 to integrate into
regions of our genome that physically associate with nuclear speckles. In this way, our most recent research
has clarified the granularity of nuclear architectural structure that most favors and most attracts HIV-1 to its
chromosomal sites of integration. Moving forward, we will determine several unknown aspects of this
fundamental virus-host interaction, including the mechanistic basis of CPSF6 action in HIV-1 intranuclear
targeting as well as the functional consequences of mistargeting, wherein HIV-1 is known to
uncharacteristically integrate into heterochromatic lamina-proximal sequences out towards the periphery of the
nuclear structure. We furthermore will investigate the participations of other host factors that we have
earmarked as behaving biochemically similar to CPSF6 for their roles in HIV-1 trafficking in the nucleus to
preferred sites of integration. We will also investigate the functional consequences of these virus-host
interactions in monocytic cell types, wherein HIV-1 replication complexes can be sensed by cellular innate
machinery to counteract the infection process. The translational relevance of this basic scientific research is
highlighted through the mechanism of action of capsid protein inhibitors such as lenacapavir, which are in late
stage clinical trials and are known to inhibit the interaction of the HIV-1 capsid with Nup153 and CPSF6
proteins in vitro, and to induce HIV-1 integration retargeting in cells. Our proposed work in total will address
fundamental aspects of virus-host interactions that occur during HIV-1 infection to shield the virus from sensing
in innate immune cells, navigate integration to preferred genomic DNA sites, as well as the consequences of
misguided integration on virus function and reactivation from latency.

## Key facts

- **NIH application ID:** 10841496
- **Project number:** 5R01AI052014-22
- **Recipient organization:** DANA-FARBER CANCER INST
- **Principal Investigator:** Alan N. Engelman
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $612,217
- **Award type:** 5
- **Project period:** 2003-01-15 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10841496

## Citation

> US National Institutes of Health, RePORTER application 10841496, HIV-1 Preintegration Trafficking and Nuclear Localization (5R01AI052014-22). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10841496. Licensed CC0.

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