We investigate a wide range of small DNA viruses and how they have evolved distinct strategies to usurp or inactivate host DNA Damage Response (DDR) signals. These DNA viruses can be modified to develop new gene therapy vectors (AAV), target cancer cells (MVM), or dissected to determine how they cause cancer (HBV).


Small DNA Viruses and DNA Damage

Adeno-Associated Virus (AAV)

Adeno-associated viruses type 2 (AAV2) are single-stranded DNA viruses of the Parvovirus family that have been modified to express transgenes in the clinic as recombinant AAV (rAAV) gene therapy vectors. Despite the strong evidence for the role of DDR components during AAV virus infection, the molecular mechanisms by which these factors are usurped and utilized during virus replication remain poorly characterized. Part of the lab’s focus is to elucidate how AAV2 utilizes DDR proteins and architectural proteins to drive localization, chromatinization, and recombinationThese studies are important for developing better rAAV vectors that persist long-term without causing adverse effects. These studies are also critical for developing a better mechanistic understanding of how small DNA viruses navigate the nuclear milieu to establish themselves long-term or cause cell death.

Minute Virus of Mice (MVM)

Using the non-integrative oncolytic parvovirus Minute Virus of Mice (MVM), we dissect how host signals modify chromatin dynamics. DNA viruses are obligate intracellular pathogens that express and replicate their genomes in the nucleus where DNA is wrapped around histones to form chromatin. There are two broad states of chromatin: transcriptionally active euchromatin and repressive heterochromatin. These chromatin states are determined by post-translational modifications of histones, regulating gene expression on both the cellular and viral genomes. While it is known which chromatin states are correlated with expression, there is a significant knowledge gap in understanding how chromatin dynamics regulate viral life cycle. Understanding how chromatin modifications regulate viral gene expression can inform the development of virally derived tools, such as gene therapy vectors and oncolytics.

We investigate how viruses localize to distinct cellular sites within the host cell’s nucleus. We have adapted high throughput chromosome conformation capture-based methods to map the sites in host cells where the viral genome can localize. Using these assays, we have discovered that the parvovirus MVM has a predilection for cellular DNA damage sites, as well as Type A open chromatin, some of which are also fragile genomic regions. Our goal is to investigate the proteins at the interface between the viral and host genomes, how virus-host interactions change over the course of infection and how this influences cellular DNA damage signaling over time.

Hepatitis B Virus (HBV)

The persistent HBV episome, known as covalently closed circular DNA (cccDNA), acts as a transcription template that is located within the nucleus of host hepatocytes. This forms the reservoir of HBV genomes in liver cells, increasing the possibility of HBV-induced liver cancer. Our goal is to develop new technologies to monitor where cccDNA molecules localize in the nuclear compartment and identify where HBV cccDNA reservoirs persist. Upon localization, we will determine the consequence of HBV cccDNA molecules on cellular genome integrity that may contribute to oncogenic transformation. While an effective HBV vaccine and antivirals have been available to the public for several decades, Hepatitis B Virus has continued to be a major public health concern across the globe. The findings of our studies will contribute to the development of novel antivirals that target the HBV reservoir in infected cells and shed light on the process by which HBV infection leads to liver cancer.