Horizontal Gene Transfer

Bacterial HGT occurs via three broad mechanisms; conjugation, transformation and viral transduction. It is transduction of genes by viruses and virus-like elements that is the main focus of Dr Fogg’s lab.

Viruses that infect bacteria (bacteriophages) are generally accepted to be the most influential mechanism of HGT. During phage replication, bacterial DNA can be packaged into a small proportion of phage particles either instead of or as well as the phage genome. Gene transfer agents (GTAs) are related to phages however, unlike phages, GTAs randomly package all DNA in the host cell with no preference for their own genes at all. Indiscriminate DNA transfer is a highly unusual trait and could lead to the spread of any gene between bacteria, which is of great concern if these genes encode virulence factors or antibiotic resistance.

The true prevalence of GTAs is obstructed in sequenced genomes by their apparent similarity to bacteriophages, however, environmental studies detected the exchange of antibiotic resistance genes by GTAs at extremely high frequencies. Existence and movement of resistance genes within environmental reservoirs is known to have a major impact on the incidence of antibiotic resistance in strains of clinical or economic importance.

Research in the Fogg lab aims to exploit novel bacteriophages and GTAs for biotechnological and medical applications. The lab also aims to address a number of fundamental aspects of GTA biology, including: regulation of GTA production, mechanisms involved in GTA assembly, the prevalence of GTAs in animal or plant pathogens and the impact of GTAs on bacterial evolution. The Fogg lab recently identified the first direct activator of a GTA and its place in the hierarchy of cellular regulators, which has provided a definitive link between global host processes and GTA production.