Nature Biotechnol. doi:10.1038/nbt.1604 (2010)

The spread of hepatitis C in cultured human liver cells can now be viewed non-invasively with a fluorescent microscope.

Tracking this viral infection in cells has historically required destructive sampling methods. Charles Rice at the Rockefeller University in New York City and his colleagues took advantage of a protein that is anchored to key cell organelles and is normally cleaved by the virus to allow it to hide from the immune system. They fluorescently tagged the protein, added a segment that would target it to the cell's nucleus and introduced it into liver cells. As the virus infected cells, it clipped the protein, freeing it from its anchor and resulting in its visible migration into the nucleus.

The researchers monitored infection of live cells in real time and then watched the process reverse when they added a viral inhibitor to infected cells.