June 13, 2007 -- Scientists probing the details of viral infection have discovered an intriguing surprise: in mice, herpes viruses hijack their host cells' tools for fixing DNA damage and use those tools to enhance their own reproduction.
The DNA damage response normally fixes DNA errors caused by radiation or other environmental factors, or mistakes accidentally introduced when cells copy their genetic material prior to dividing.
In the murine (or mouse-infecting) herpes virus they studied, researchers at Washington University School of Medicine in St. Louis identified a protein that can trick the mouse cell into turning on the DNA damage response. They also showed that Epstein-Barr virus, a human herpes virus, has a similar protein. Scientists found that blocking murine herpes virus from activating the DNA damage response caused viral replication rates to plummet.
"We don't want to treat viral infection by blocking DNA damage response systemically because this process is used constantly throughout the body and is very important to preventing cancer," says lead author Vera Tarakanova, Ph.D., a postdoctoral fellow. "However, by targeting the viral protein responsible for activating the DNA damage response, we may be able to block viral replication. In addition, determining how the DNA repair response helps viral replication may enable us to develop novel strategies to treat infection."
The paper appears online this week in Cell Host & Microbe. Scientists have known for some time that viral infection of cells activates the DNA damage response. But researchers had assumed that this activation occurred because repair mechanisms were mistaking replicating viral DNA for damaged or dysfunctional cellular DNA.
"Viruses sometimes structure their own DNA differently than cellular DNA," Tarakanova notes. "Many of us thought that such differences might be triggering the DNA damage response." Working in the laboratory of H
Source:Washington University School of Medicine