Scientists shed new light on mechanism by which bacteria exchange genes

Posted on 9 October 2019

Scientists are now a step closer to understanding the mechanisms behind how a group of viruses facilitate the exchange of genes between bacteria.

Rodobacter capsulatus bacteria - the purple photosynthetic bacteria in which GTAs were first discovered

In a paper published in the Journal of Virology, researchers from the University of York have shed new light on a class of domesticated viruses called Gene Transfer Agents (GTAs) that are produced by bacteria.

GTAs can package and transfer any DNA present in the cell producing them, allowing any gene to be spread – including antibiotic resistance genes. 

The researchers have identified a protein that plays a key role in enabling GTAs to package and transfer the entire genome of their host bacteria. They also pinpointed structural differences in this protein found in GTAs compared to the same type of protein in standard viruses, which prefer to package their own viral DNA.

GTAs are difficult to identify because not much is known about their defining characteristics. So far, they have been studied in a limited number of bacteria including pathogens such as Bartonella - a group of bacteria that can cause a wide variety of diseases in animals from heart infections to meningitis.

The new research could lead to better identification of these virus and others that infect bacteria using similar mechanisms.

Lead author of the study, Dr Paul Fogg from the Department of Biology, said: 'Understanding the mechanics of how GTAs package and transfer DNA is important because this process has an influential role in driving rapid bacterial evolution and the spread of antibiotic resistance.

'This study paves the way for improved identification of new GTAs. Understanding the structure of GTAs could also eventually lead to scientists being able to engineer GTAs for their own use in biotechnological applications such as in vivo DNA processing, genome editing or gene delivery.'

Identification of the first gene transfer agent (GTA) small terminase in Rhodobacter capsulatus and its role in GTA production and packaging of DNA is byD. Sherlock, J.X. Leong and P.C.M. Fogg from the University of York.