Under pressure: mechanism of DNA injection by herpes viruses
July 26, 2013 § Leave a comment
According to research just out in the Journal of the American Chemical Society, the herpes viruses that cause shingles, chickenpox, Hodgkin’s lymphoma and other serious illnesses push their DNA into human cells with great force. In fact, the investigators involved in the research say that the herpes simplex virus 1, which causes cold sores, has an internal pressure eight times greater than that of a car tire. The virus uses this pressure to shove its DNA into cells.
“The mechanism of DNA release from herpes viruses, as well as the majority of other viruses, is poorly understood,” says Alex Evilevitch at the Carnegie Mellon University, who spearheaded the work. “This work provides important evidence of how this happens for herpes viruses.”
The investigators demonstrated that HSV-1 goes into a cell, docks with portals that are on the cell’s nucleus and pushes its DNA into the organelle with high pressure. The high pressure is caused by tight packing of the capsid, the shell that contains the viral genome.
Bacteriophages, which are viruses that infect bacteria, are known to use the same high-pressure mechanism to shoot their DNA into nuclei. This suggests that evolution has found this method to be very effective for viral infection and has repurposed it for other viruses.
The mechanism also gives researchers a new handle on developing antiviral therapies. “As the DNA inside herpes viruses has a unique condensed state, which is not present anywhere else in the cell, decreasing this pressure will make the virus noninfectious,” explains Evilevitch. “This provides a new drug target that is resistant to mutations since it will target a universal physical mechanism, rather than specific viral proteins.”