Defining the nuclear import pathways of HIV-1

Abstract
Human Immunodeficiency virus (HIV-1), like all primate lentiviruses possesses the ability to infect
non-dividing cells by engaging with components of the nuclear pore complex and mediating the
nuclear translocation of the viral ribonucleoprotein complex (RNP) for subsequently integration
into the host cell genome. The viral capsid protein (CA) interacts with numerous host factors
involving constituents of the nuclear pore complex (NPC) to accomplish the process of nuclear
import. Unfortunately, the exact mechanism by which HIV-1 translocates through the nuclear pore
complex remains one of the least understood steps of the viral life cycle. In addition, recent
evidences supporting the notion of NPCs being more heterogeneous than previously thought
further confounds this situation. We have developed an inducible nuclear pore blockade that
allows the rate of nuclear import of functional, infectious viral genomes to be monitored in any
relevant cells types. Using this technique, we observe that certain CA mutants are insensitive to
a Nup62 mediated nuclear pore blockade in cells which potently block infection by wild type CA,
demonstrating that HIV-1 can utilize distinct nuclear import pathways during infection. In this
application, we will determine the degree to which NPC are heterogeneous and map the specific
nuclear pore constituents that makeup the NPCs utilized by HIV-1 during nuclear entry. With our
nuclear pore blockade, we now have the capability to block NPCs using different nuclear pore
constituents. As such, this application aims to define and visualize the specific nuclear pore
constituents that interact and mediate the nuclear import of HIV-1 and how specific NPC usage
affects viral integration in target cells. Collectively this application would close critical gaps to our
understanding in to the nuclear import of HIV-1.

Grant Number: 5R01AI162694-04
NIH Institute/Center: NIH
Principal Investigator: Edward Campbell