dr. ronald e. mcnair acknowledgements - University of St. Thomas

ABSTRACT
Human immunodeficiency virus, HIV, is the causative agent of AIDS, a pandemic
affecting over 30 million people worldwide. Understanding how drug resistance develops
in HIV is essential for improving antiretroviral therapy and is an important research
area in the fight against HIV/AIDS. While much is known about HIV-1, the virus
that accounts for majority of global infections and the mutations it acquires during drug
resistance, information on HIV-2’s drug resistance is limited to a handful of studies.
HIV-2 is prevalent in West Africa and the limited spread of the infection contributes to
the lack of available research on this virus type. The present study will investigate HIV-
2 drug resistance to nucleoside reverse transcriptase inhibitors, a drug class that inhibits
activity of the reverse transcriptase enzyme, a major generator of mutations in HIV. We
will create HIV-2 mutants containing HIV-1 resistant conferring mutations and observe
how the mutants influence drug susceptibility and mutation frequency, two factors that
stimulate drug resistance. NRTI-resistant reverse transcriptase increases mutation
frequency in HIV-1, which results in a higher selection for drug resistant mutations
and further diminishes NRTI potency. Because HIV-1 and HIV-2 have similar reverse
transcriptase enzymes, we hypothesized that HIV-2 resistant RT would also increase
mutation frequency and HIV-1 mutations will confer resistance in HIV-2. Current
results from two, single round replication assays and flow cytometry show that HIV-2
has an average mutant frequency of 0.239 ± 0.041 (first replicate) and 0.273 ±
0.033 (second replicate). HIV-2 mutants will be generated by site-directed mutagenesis,
and we can observe how these mutations influence mutant frequency and drug
susceptibility. The ultimate goal is to develop a better understanding of HIV-2 drug
resistance that could be used to create potential treatment options for the HIV-2 infection.
INTRODUCTION
A retrovirus is a RNA virus that encodes for the reverse transcriptase (RT)
enzyme; RT converts viral RNA into DNA that can be integrated in a host
cell’s nucleus. HIV is a retrovirus that attacks and replicates inside of T cells,
a group of white blood cells that play a role in immune defense. The HIV life
cycle begins when a virus particle binds and fuses into the host cell and releases
its genetic material as RNA. The reverse transcriptase enzyme converts viral
RNA into DNA, which is then transported into the host’s nucleus and spliced
into human genetic material by the integrase enzyme. Proviral DNA is
transcribed, using human enzymes, into mRNA and complete copies of HIV
genetic material. The mRNA is used as a blueprint to create long chains of
HIV protein. Protease cuts these chains into individual proteins, which join
with HIV genetic copies to form a new virus particle. As the newly assembled
virus particle is released from the host cell, it takes part of the cell’s membrane
containing proteins necessary to bind to and infect new cells (Tavassoli, 2011).
HIV is the causative agent of acquired immunodeficiency syndrome, AIDS,
a pandemic affecting over 30 million people worldwide. There are two types
of HIV; HIV-1 is the common virus accounting for the majority of infections
globally, and HIV-2 is centralized to West Africa. HIV-1 and HIV-2 are
genetically similar; their virion (virus particle) structures are alike and they
EXPLORING THE
INFLUENCE OF HIV-1
RESISTANT
CONFERRING
MUTATIONS ON
ANTIRETROVIRAL
DRUG RESISTANCE IN
HIV-2
Mondraya Howard ’13
University of St. Thomas
Mentor
Louis Mansky, Ph.D.
Professor of Microbiology and
Diagnostic and Biological
Sciences
University of Minnesota
41