Date Approved

5-2015

Document Type

Thesis

Degree Name

Master of Science in Biomedical Sciences

Department

Cell Biology

College

Graduate School of Biomedical Sciences

First Advisor

Dmitriy Markov, PhD

Committee Member 1

Mikhail Anikin, PhD

Committee Member 2

Sergei Borukhov, PhD

Subject(s)

HIV, Endosomal Sorting Complexes Required for Transport, Viral Proteins, Ribonucleases

Disciplines

Cell Biology | Genetic Processes | Immunopathology | Laboratory and Basic Science Research | Life Sciences | Medical Cell Biology | Medicine and Health Sciences | Molecular Biology | Molecular Genetics | Virus Diseases | Viruses

Abstract

A virus is only as powerful as its ability to spread. Enveloped retroviruses, namely HIV-1, use exocytosis pathways that normal host cells use to release particles from the plasma membrane. The main pathways of interest in this study are the Endosomal Sorting Complex Required for Transport (ESCRT) and adjacent ALIX pathways. The ESCRT pathway is especially important for degradation of receptor/cargo complexes that form Multi-Vesicular Bodies (MVBs). Currently, there is no known therapy that targets this endosomal pathway, which would prevent the spread of the virus to other cells. The virus has adapted to jump from pathway to pathway when it becomes environmentally favorable.

To begin viral release, the virus aggregates on the cell membrane using the ESCRT complex. The viral protein, NC domain of HIV-1 Gag, binds to Bro1 domain of human ALIX, which is an important component of ESCRT 1 by recruiting ESCRT 3 complexes, which further enhances aggregation and maturation of the virus at the membrane. ALIX is vital for viral maturation and eventual scission from the cell, but the mechanism by which NC and ALIX bind and interact with each other is poorly understood, however previous studies have shown that there is very little protein-protein interaction specifically between NC and ALIX. Previous studies have shown a controversial claim that RNAse treatment significantly inhibits the NC-Bro1 interaction and suggests that a basic patch of ALIX, called the Bro1 domain, stabilizes the NC-ALIX interaction. We look to resolve this controversy by determining whether RNA enhances the NC-ALIX interaction.

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