Bacteriophage viruses, or phages for short, viruses that attack bacteria, have a more complex life than previously thought.
It was recently discovered that they are even capable of communicating with each other, establishing strategies to infect bacteria. That is why it is a thriving field of research, due to its possible applications in biotechnology and biomedicine.
Now, an international group of researchers led from the Institute of Biomedicine of Valencia (IBV), of the Higher Council for Scientific Research (CSIC) in Spain, reveals a new mechanism, more complex than previously believed, to control the life cycle of one of the families of phages with the ability to communicate.
This work is the result of collaboration between the group led by Alberto Marina at the IBV and that of José R. Penadés at Imperial College London, with the participation of Avigdor Eldar’s group, from Tel Aviv University. The three researchers have just received one of the prestigious Synergy Grants from the ERC (European Research Council) for collaborative frontier research. Within the framework of this project, TalkingPhages, researchers have described a new repression mechanism in phages of the SPbeta family, in which the existence of the mechanism that phages use to communicate with each other, called arbitrium, was demonstrated.
Phages have two life cycles: a lytic one, where the phage infects a bacteria, uses it to multiply and then kills it by exploding it (known as ‘lysing’) to release new viral particles; and another lysogenic, where the phage infects a bacteria and inserts its DNA into it, remaining quiescent, which allows its DNA to be copied and transmitted to offspring when the bacteria duplicates (as do herpes viruses or hepatitis delta in humans ).
“To remain in a quiescent state, the phage has to repress the lytic genes,” explains Alberto Marina, CSIC research professor at the IBV. “It does this through a master repressor protein called CI, as had been characterized for the Lambda model phage. Basically, it was assumed that all phages had a very similar lysogeny control system,” says Marina.
In the new study, the research team, led by Aisling Brady of Imperial College London, has described an entirely new and much more complex system. Phages of the SPbeta family do not have a single protein to repress the genes of the lytic cycle, but three participate in the process, with structures different from the already known CI. “The master repressor is a protein with a recombinase architecture that we have called SroF, which the phage has adapted to repress lytic genes,” describes the CSIC researcher. Being phages with a very large genome, coding for more than 180 proteins, SroF creates junctions with multiple sites in the genome, which also differentiates it from the classic lambda model.
Fuente: www.noticiasdelaciencia.com