# Engineering chimeric gene therapy vectors with enhanced packaging capacity

> **NIH NIH F32** · MASSACHUSETTS INSTITUTE OF TECHNOLOGY · 2022 · $69,802

## Abstract

Project Summary
Adeno-associated viruses (AAVs) are non-pathogenic parvoviruses that are currently the foremost gene
therapy vectors. As gene therapy is increasingly employed to treat a variety of indications, AAVs serve a
critical role in delivering therapeutic DNA. However, effective packaging of recombinant transgenes in AAV
vectors remains a paramount challenge to successful gene therapy. First, the packaging capacity of the AAV
capsid restricts transgene size to under 4.7 kb, precluding delivery of many transgenes and gene editing
cassettes. Relatives of AAV within Parvoviridae contain larger genomes, including Densovirus (DNV), a
subfamily of parvoviruses that naturally infect invertebrates. I propose to engineer chimeric DNV/AAV vectors
that support robust transduction of mammalian cells and enhanced packaging capacity relative to traditional
AAV vectors. I then plan to investigate DNV/AAV transduction, and leverage this knowledge to perform
directed evolution on DNV/AAV capsids to confer robust transduction of mammalian cells. Second, immune
recognition and clearance of AAVs following high dose vector administration remains a key issue in gene
therapy delivery, as high doses are often indispensable to achieve transgene expression at therapeutic levels.
One reason for the necessity of high dose treatments is the lacking potency of recombinant AAV vector
preparations, which have been demonstrated to have lower infectious-to-physical particle ratios relative to
AAVs packaging their endogenous genome. Previous studies have shown that these differences in AAV
production may be due to uncharacterized cis-acting packaging signals within the AAV genome. Therefore, I
aim to perform an unbiased screen for novel motifs within the AAV genome that confer enhanced genome
packaging, and to investigate how incorporation of additional cis-acting sequences affects recombinant vector
production. Together, these studies aim to address core issues in AAV mediated gene therapy by augmenting
both the size of transgenes that can be delivered and the potency of recombinant vector production.

## Key facts

- **NIH application ID:** 10381488
- **Project number:** 5F32AI161868-02
- **Recipient organization:** MASSACHUSETTS INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Victoria Jane Madigan
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $69,802
- **Award type:** 5
- **Project period:** 2021-05-01 → 2024-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10381488

## Citation

> US National Institutes of Health, RePORTER application 10381488, Engineering chimeric gene therapy vectors with enhanced packaging capacity (5F32AI161868-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10381488. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*