John Innes Centre researchers identify repurposed viral "couriers" that accelerate the spread of antibiotic resistance

John Innes Centre scientists discover how bacteria use LypABC to repurpose ancient viruses as couriers for spreading antibiotic resistance genes.

By: AXL Media

Published: Apr 16, 2026, 7:57 AM EDT

Source: Information for this report was sourced from John Innes Centre

Ancient Viral Domesticants as Genetic Couriers

A collaborative research effort led by the John Innes Centre has uncovered how bacteria utilize "domesticated" ancient viruses to share life-saving genetic information. These particles, known as gene transfer agents (GTAs), structurally resemble bacteriophages but have been evolutionary co-opted by their bacterial hosts. Instead of acting as predatory parasites, these GTAs function as biological couriers that package segments of the host's DNA and deliver them to neighboring bacteria. This process of horizontal gene transfer allows bacterial populations to rapidly disseminate beneficial traits, most notably those that confer resistance to common antibiotic drugs.

Identifying the LypABC Control Mechanism

The breakthrough, published in Nature Microbiology, centers on the discovery of a three-gene regulatory hub named LypABC. Researchers investigating the model bacterium Caulobacter crescentus found that this specific genetic cluster is the primary driver of host cell lysis, the terminal stage where a cell ruptures to release its cargo of DNA-packed GTAs. By utilizing a deep sequencing-based screening method, the team demonstrated that deleting the lypABC genes completely halted the release of these particles, while overexpressing them led to a massive increase in cell lysis across the population.

Repurposing the Bacterial Immune System

In a surprising evolutionary twist, the LypABC system was found to share significant structural similarities with bacterial anti-phage immune systems. Typically, these protein domains are utilized by bacteria to defend against viral infections by triggering "altruistic" cell death to prevent a virus from spreading. However, the study suggests that bacteria have repurposed this defensive "abortive infection" machinery to serve a productive role. According to Dr. Emma Banks, the study's first author, this highlights an extraordinary level of biological plasticity where an immune system originally designed for defense is now used to facilitate the collaborative sharing of DNA.