International researchers have discovered that viruses pick up cues from their environment to carry out various tasks. This suggests that they have the capacity to sense their surroundings and that of their host and to decide when it is appropriate to spread an infection, attack the host cells, multiply, or suspend activity at any given time.
During their study, according to the researchers, may reveal additional, as yet unidentified, features of the interaction between the virus and the host and pave the way for the creation of a new generation of antiviral medications. They investigated bacteriophages—also known as “phages,” viruses that attack and infect bacteria—and found that their DNA contains binding sites for a protein known as CtrA.
Interestingly, a phage never produces CtrA, so why does its DNA have a binding site for the protein? In searching for an answer to this question, researchers discovered an unprecedented power of phages.
Viruses are smarter than you think
In fact, CtrA is connected to the development of unique outgrowths in bacterial cells. The bacteria can move and carry out additional functions like adhesion, reproduction, and infection of a host thanks to these outgrowths called flagella. The CtrA protein, which regulates flagella formation in the host bacteria, is thought to be the intended target of the binding site in phage DNA, according to the researchers.
Furthermore, CtrA binding sites are not only found in a certain species of phage. They are present in a variety of flagellotropic phage types. The research explains why and how phages choose to target only bacteria with developed flagella.
The researchers examined a phage that affects the caulobacterales, an order which includes a variety of gram-negative bacterial species. Caulobacter bacteria cells have the unique property of producing non-motile stalked cells when there is enough of food available. When there is a lack of food, the cells produce flagella and give rise to swarmers, bacteria that may move freely.
The phage exclusively infects swarmer bacteria, but how does it distinguish amongst the many caulobacterales members? Surprisingly, the researchers discovered that the CtrA protein determined whether the bacterial cell divided into stalkers or swarmers. They believe that CtrA levels in caulobacter allow the phage to select the appropriate host.
“We hypothesise the phages are monitoring CtrA levels, which fluctuate throughout the life cycle of the cells, to determine when the swarmer cell is developing into a stalk cell and turning into a factory of swarmers, and at that point, they burst the cell because there will be many swarmers nearby to infect,” Ivan Erill, one of the authors and a computational biologist at the University of Maryland Baltimore County, told PhysX.
A phage can do much more than just spot flagella
Phages gives them ability to monitor their surroundings and make decisions that are more in line with their biology because to the presence of CtrA binder sites. Interestingly, this could be only one of many abilities; the researchers believe that phages may also contain receptors that allow them to listen to activities taking-place inside the host cells. However, this is only a hypothesis, and further research is needed to prove-it, as well as many other alternatives.
More knowledge of such binding sites and receptors could lead to the development of better and more effective antiviral medicines. The current work, for example, emphasises that the CtrA binder is responsible for a flagellotropic phage’s ability to monitor its environment. Scientists can now use this information to develop a medication that could trigger false CtrA monitoring & fool the viruses.
The most intriguing finding of this research is that “the virus uses cellular information to make decisions, and if it’s happening in bacteria, it’s almost certainly happening in plants & animals, because if there’s a strategy, that’s it makes sense, evolution will discover and exploit it,” said Professor Erill.
The study is published in the journal Frontiers in Microbiology.