Francisella tularensis WIKIMEDIA, CDCThe list of potential uses for the CRISPR/Cas system grows longer by the day. Now fighting viruses may soon be added to that list, according to a study published today (April 27) in PNAS. Microbiologist David Weiss and immunologist Arash Grakoui of Emory University in Atlanta and their colleagues used a version of the Cas9 enzyme from the bacteria Francisella novicida to bind hepatitis C virus (HCV) RNA and prevent the pathogen from replicating inside human cells.
Last summer, another group showed that CRISPR/Cas9 could be used to seek out and excise HIV DNA from the genomes of latently-infected cells. The Emory team later found that F. novicida Cas9 (FnCas9) blocks HCV in a different way; it binds viral RNA in the cytosol such that, “if there are off-target effects, it wouldn’t be editing the genome,” said study coauthor Aryn Price, a graduate student in Grakoui’s lab.
FnCas9 also differs from other Cas enzymes because it doesn’t cut up RNA, it creates a roadblock for the proteins trying to copy RNA or translate it into viral proteins. Although this study is the first to target CRISPR/Cas9 to RNA within human cells, members of Jennifer Doudna’s lab at the University of California, Berkeley, ...
