# Structure and Function of DNA Polymerase Theta

> **NIH NIH R01** · THOMAS JEFFERSON UNIVERSITY · 2021 · $387,897

## Abstract

Project summary
 DNA polymerase θ (Polθ) is a unique protein in higher eukaryotes because it contains a N-terminal
superfamily 2 (SF2) helicase domain (Polθ-helicase) and a C-terminal A-family polymerase domain (Polθ-
polymerase). Polθ is essential for the DNA double-strand break (DSB) repair pathway alternative end-joining
(alt-EJ), also called microhomology-mediated end-joining (MMEJ). Polθ also promotes the proliferation of
cancer cells defective in homology-directed repair (HDR) and confers resistance to chemotherapy agents. The
structural and molecular basis of Polθ activity, however, remains unclear. For example, the activities of Polθ-
helicase are poorly understood, and the structural basis for how Polθ-polymerase uniquely acts on single-
strand DNA (ssDNA) overhangs and promotes MMEJ remains to be elucidated. Furthermore, how
Polθ influences CRISPR-Cas9 genome editing remains poorly understood. In preliminary studies, we have
discovered novel functions for Polθ-helicase including ssDNA annealing and DNA unwinding, and have
identified optimal substrates for Polθ-polymerase MMEJ which will enable crystallographic studies of MMEJ.
Lastly, we have discovered an unexpected and essential role for Polθ in CRISPR-Cas9 genome editing. We
will utilize a collaborative approach among three labs (Pomerantz, Chen and Sfeir) to elucidate the structural
and molecular basis of Polθ activity in DNA repair and genome editing by developing the following aims: 1. To
investigate annealing, unwinding and anti-recombinase activities of Polθ; 2. To elucidate the structural basis of
Polθ-polymerase dependent MMEJ; 3. To investigate Polθ involvement in CRISPR-Cas9 genome editing using
ssDNA templates. In summary, these studies will provide new and significant insight into the structure and
function of Polθ, and characterize an unexpected role for Polθ in CRISPR-Cas9 genome editing.

## Key facts

- **NIH application ID:** 10094002
- **Project number:** 5R01GM130889-04
- **Recipient organization:** THOMAS JEFFERSON UNIVERSITY
- **Principal Investigator:** Richard T Pomerantz
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $387,897
- **Award type:** 5
- **Project period:** 2019-02-15 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10094002

## Citation

> US National Institutes of Health, RePORTER application 10094002, Structure and Function of DNA Polymerase Theta (5R01GM130889-04). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10094002. Licensed CC0.

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