IMMUNOLOGY | West Nile Virus Triggers Apoptosis
Even as West Nile virus (WNV) spreads, researchers still know little about its infective choreography. To track the steps, David B. Weiner, an associate professor of pathology and laboratory medicine at the University of Pennsylvania, and colleagues marked WNV capsid protein with green fluorescent protein (GFP) and transfected cultured human cells and murine muscle and brain. GFP-marked capsids, which form the viral shell, disrupted mitochondrial membranes, triggering apoptosis and inflammation. Deleting part of the capsid gene stunted the capsid protein and dampened the death signal (J.S. Yang et al., "Induction of inflammation by West Nile virus capsid through the caspase-9 apoptotic pathway," Emerg Infect Dis, 8:1379-84, December 2002).
"We mapped the apoptotic part of the protein to the carboxyl terminus," Weiner says. "This sequence difference is known only in Kunjin virus--the rest of the flaviviruses don't have it. So West Nile virus might ...
