# Imaging early steps of HIV-1 infection and virus-host factor interactions

> **NIH NIH R01** · EMORY UNIVERSITY · 2024 · $564,977

## Abstract

Key steps of early HIV-1 infection include reverse transcription, nuclear import of replication complexes and
transport to nuclear speckles followed by viral DNA integration into host genome. At some point before
integration, the capsid shell surrounding the viral ribonucleoprotein complex must disassemble (uncoat) to
release the viral pre-integration complexes. It is currently unclear where in the cell uncoating occurs and whether
the capsid (CA) protein is progressively or synchronously lost from the capsid shell, yet optimal core stability is
essential for evading the host innate immune responses and for nuclear import of functional viral complexes.
Highly divergent findings regarding HIV-1 uncoating have been reported by several groups based upon the
visualization of single virus uncoating in live cells. These conflicting results stem, in part, from the use of indirect
CA labeling approaches and lack of minimally invasive direct fluorescent labeling of HIV-1 capsid. We
hypothesize that HIV-1 uncoating is a multi-step process that involves permeabilization of the capsid shell in the
cytoplasm, remodeling at the nuclear pore, and loss of CA in the nucleus. We will use a novel minimally invasive
direct CA labeling strategy, which is based on site-directed incorporation of non-canonical amino acids and click-
labeling with an organic dye, to elucidate single HIV-1 core permeabilization and uncoating events resulting to
infection (Aim 1). Another gap in knowledge pertains to post-uncoating processes leading to HIV-1 integration
and sub-nuclear compartments where integration occurs. We hypothesize that the viral pre-integration complex
separates from the capsid shell and travels to the edge of a nuclear speckle where it engages the integrase-
binding host factor LEDGF/p75 for integration into host genome. We will employ a novel live-cell single viral DNA
visualization technology to track nuclear transport and productive integration of single viral complexes that
establish actively transcribing viral RNA foci (Aim 2). Finally, we will use a powerful panel of biochemical,
biophysical, structural biology, virology, and microscopy techniques to characterize a novel HIV-1 CA binding
host factor, RBM14, which we hypothesize to modulate pre-integration steps of infection after nuclear import
(Aim 3). These experiments are expected to elucidate the controversial HIV-1 uncoating process, reveal the
dynamic events leading to productive integration and sites of integration, as well as delineate the role of RBM14-
capsid interactions in early infection, thus informing novel antiviral strategies.

## Key facts

- **NIH application ID:** 10838523
- **Project number:** 5R01AI129862-08
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** Mamuka Kvaratskhelia
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $564,977
- **Award type:** 5
- **Project period:** 2022-06-17 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10838523

## Citation

> US National Institutes of Health, RePORTER application 10838523, Imaging early steps of HIV-1 infection and virus-host factor interactions (5R01AI129862-08). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10838523. Licensed CC0.

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