Mechanistic Study and Gene Targeting to Block HIV Assembly by IN-Binding Protein - Despite major advances in treatment, Human Immunodeficiency Virus 1 (HIV-1) remains a significant
public health issue that currently has no cure. Lifelong treatment is required due to the remaining latently
infected cells. Unlike currently available drugs, a self-sustained therapeutic that targets events undergone by
infected cells could potentially control the viral load in patients, leading to a functional cure. The HIV-1 life cycle
consists of early events, the events from entry to proviral integration into the genome, and late events, which
encompass transcription through budding and virion maturation. HIV-1 assembly, one of the late events,
involves sequential assembly of Gag and Gag-Pol structural proteins along with HIV-1 genomic RNA to form
assembly intermediate complexes, that eventually reach the plasma membrane to bud out as infectious virions.
While much has been studied about assembly and viral determinants required for these events, the nature of
assembly intermediates and the association of viral and cellular protein in these complexes is not well
understood. Furthermore, while Gag is the major viral structural protein that is involved in assembly, Gag-Pol,
which is incorporated at 1:20 ratio to that of Gag, also plays a role in these events. Mutations in Pol portion of
Gag-Pol such as integrase (IN) and reverse transcriptase (RT) have been shown to interfere with the assembly
events. The role of Gag-Pol or the host factors associated with Pol is largely unknown at this point. My project
is focused on understanding of the role of a Pol-binding host factor in assembly and use this knowledge to
develop therapeutics to inhibit assembly. .
A fragment of the HIV-1 IN-binding host protein, INI1/hSNF5, has been previously shown to inhibit HIV-
1 late events prior to budding. While it is known that the minimal IN-binding fragment of INI1/hSNF5 (termed
S6) inhibits late events prior to budding, the exact stage or the mechanism is unknown. In this proposal, I
propose (1) examining assembly intermediate complexes to determine if this inhibitory fragment affects
assembly complex formation and (2) site-specifically inserting DNA coding for this fragment into the genome of
T-cells and assessing off-target effects and ability to inhibit HIV-1 particle production. Determining the effects
of S6 on assembly intermediates will shed light on mechanisms of early assembly and improve our knowledge
of the role of IN-binding proteins in HIV-1 assembly. Gene therapy approaches to express S6 in T cells hold
promising therapeutic potential for HIV-1. Inserting S6 site-specifically, using CRISPR/Cas9, a targeted
nuclease that precisely modifies genomes, to inhibit assembly not only provides a novel approach to inhibit
assembly, but also helps improve our knowledge of genome engineering to inhibit HIV-1 replication.
