Researchers at the John Innes Centre announced on Apr. 16 that they have uncovered new details about how bacteria share DNA, a process linked to the spread of antimicrobial resistance. The study focused on gene transfer agents (GTAs), which are particles that resemble viruses but have been adapted by bacteria to transport genetic material between cells.
This discovery is significant because it helps explain how traits such as antibiotic resistance can quickly move through bacterial populations, posing challenges for treating infections. Understanding this process could help in developing strategies to limit the spread of resistance genes.
The research team used deep sequencing techniques to study GTAs in the bacterium Caulobacter crescentus. They identified a set of three genes, known as LypABC, that are essential for releasing GTA particles from host cells through a process called cell lysis. When these genes were removed, bacteria could not release GTAs; when overexpressed, many cells underwent lysis and released more GTA particles.
LypABC was found to resemble parts of bacterial immune systems usually involved in defending against viruses. However, researchers say it appears these components have been repurposed by bacteria to enable gene sharing via GTAs rather than defense. The study also discovered a regulatory protein needed for strict control over both GTA activation and cell lysis, since misregulation can be toxic to the cells.
The findings highlight how flexible bacterial systems can be and provide insight into fundamental mechanisms behind horizontal gene transfer and antimicrobial resistance development. According to the research team, their next goal is to determine exactly how LypABC is activated and controls cell rupture during GTA release.
"A bacterial CARD-NLR-like immune system controls the release of gene transfer agents," appears in Nature Microbiology.
