# Host DNA repair pathways in human cytomegalovirus replication

> **NIH NIH R01** · UNIVERSITY OF ARIZONA · 2024 · $114,809

## Abstract

PROJECT SUMMARY
Human Cytomegalovirus (HCMV) is a double-stranded DNA virus that establishes life-long infection in the
human host. The overarching objective of our work is to define critical virus-host interactions important for virus
replication and latency, which provide targets for antiviral strategies aimed at limiting viral pathogenesis. HCMV
encodes a single DNA polymerase (UL54). As herpesviruses encode their own DNA polymerase, it has been
broadly presumed that they do not require host polymerases for the replication of their genomes. However,
herpesvirus genomes are complex with high-GC content and repeat sequences that constrain the B-family
DNA polymerases, such as UL54. Through our collaborative effort, we demonstrated a striking role for
specialized host translesion polymerases (TLS pols) in HCMV genome replication and stability. TLS pols
function in lesion bypass at the replication fork or in single-stranded DNA gap filling or homology-directed
repair that occurs post-synthesis (behind the fork). TLS pols also maintain fragile site stability during
unperturbed DNA synthesis. TLS pols include the Y-family polymerases eta (η), iota (ι), kappa (κ) and Rev 1,
as well as the error-prone, B-family polymerase zeta (ζ). Strikingly, we found that Y-family TLS pols (η,ι,κ, and
Rev1) and pol ζ are important to maintain HCMV genome stability. Further, our results indicate that pols
η, ι, and κ generate single nucleotide variants across the viral genome. These findings indicate important roles
for host TLS pols in ensuring viral genomic integrity and potentially in generating viral genome diversity. We
also found that depletion of TLS pols differentially impacts viral genome synthesis and replication. Defining
how HCMV maintains genomic stability and the significance of host TLS pols and DNA damage repair (DDR)
pathways on the viral lifecycle is important for understanding mechanisms of virus replication and latency.
Further, exciting new data indicates a role for host TLS pols in the evolution of resistance to nucleoside
antiviral therapies, such as ganciclovir. We hypothesize that HCMV actively recruits TLS pols and coopts
corresponding DDR pathways to maintain genome integrity and regulate viral replication and latency. Aim 1 will
determine the mechanisms by which HCMV recruits host TLS pols and other DDR repair factors to viral
replication compartments and the subdomains in which they function. Aim 2 will define the mechanisms by
which host TLS pols and other DDR repair factors act on viral sequences to ensure genome stability and
contribute to antiviral resistance. Aim 3 will determine the significance of host DDR pathways to viral latency.
These aims are driven by our published work and exciting preliminary data identifying virus-host interactions
that control host TLS pols and DDR pathways. Our multi-PI collaborative work establishes the importance of
host TLS pols for the stability and diversity of viral genomes and would not be possibl...

## Key facts

- **NIH application ID:** 11082895
- **Project number:** 3R01AI177392-02S1
- **Recipient organization:** UNIVERSITY OF ARIZONA
- **Principal Investigator:** Giovanni Bosco
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $114,809
- **Award type:** 3
- **Project period:** 2023-06-16 → 2025-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11082895

## Citation

> US National Institutes of Health, RePORTER application 11082895, Host DNA repair pathways in human cytomegalovirus replication (3R01AI177392-02S1). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/11082895. Licensed CC0.

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