# Targeted control of self-transmissible plasmids by using engineered interfering plasmids

> **NIH NIH R01** · DUKE UNIVERSITY · 2022 · $364,787

## Abstract

Targeted control of self-transmissible plasmids by using engineered interfering plasmids
Abstract
 Mobile genetic elements (MGEs) are genetic materials that can move within a genome or between
species, a phenomenon known as horizontal gene transfer (HGT). It is well recognized that HGT plays a critical
role in introducing, maintaining, and spreading diverse functional traits such as metabolic traits, virulence factors,
and antibiotic resistance. For example, in the clinical setting, antibiotic resistance can spread from the resident
microflora to invading pathogens or vice versa. Conversely, use of antibiotics can modulate the overall
conjugation dynamics by affecting the conjugation efficiency (rate of gene exchange) or by selecting for
populations containing mobile plasmids. Therefore, it is critical to develop strategies that can modulate gene
persistence by targeting HGT.
 To this end, we propose to develop a synthetic-biology based intervention strategy that enables
targeted suppression or elimination of self-transmissible plasmids. The strategy exploits the vulnerability
of conjugation to deliver an engineered plasmid to both suppress the conjugation rate and to accelerate loss of
the target plasmid via incompatibility. During conjugation, a mating bridge is established between the donor
cell and the recipient cell, allowing one copy of the self-transmissible plasmid to be transferred to the recipient.
However, at a smaller efficiency, the transfer apparatus allows a mobilizable (but not self-transmissible) plasmid
to be transferred from the recipient to the donor cell. This process is known as retro-transfer. Our design exploits
retro-transfer to deliver our engineered plasmid. Upon entry, an incompatibility element carried by our engineered
plasmid will expel the self-transmissible plasmid that picks up our plasmid in the first place. This exclusion is
enabled by proper control of the selection dynamics. We term this intervention strategy DoS (Denial of Spread)
or DDoS (Distributed Denial of Spread), when generalized to the simultaneous targeting of multiple self-
transmissible plasmids. Our preliminary modeling and experimental analysis have demonstrated the proof of
concept of DoS strategy. Our proposed work will develop and optimize this intervention strategy in depth and
apply it to eliminate self-transmissible plasmids encoding antibiotic resistance in pathogenic bacteria. We
envision that our proposed work will establish a transformative platform for precise control of gene persistence
and flux in microbial communities.

## Key facts

- **NIH application ID:** 10434929
- **Project number:** 5R01EB031869-02
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** LINGCHONG YOU
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $364,787
- **Award type:** 5
- **Project period:** 2021-07-01 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10434929

## Citation

> US National Institutes of Health, RePORTER application 10434929, Targeted control of self-transmissible plasmids by using engineered interfering plasmids (5R01EB031869-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10434929. Licensed CC0.

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