A video recording reveals how the human immunodeficiency virus (HIV) breaks through the outer cell membrane and uses the internal scaffolding of the cell to find its way to the central nucleus.
The virus is illuminated with a fluorescent dye derived from a jelly fish. It makes the HIV appear as bright green dots against the red background of the cell's cytoplasm - the gel-like filling of the cell outside the nucleus.
Tom Hope, leader of the team who took the photographs at the Salk Institute in La Jolla, California, will present the findings today at a meeting in Washington DC of the American Society for Cell Biology.
He said: "After it penetrates the cell's surface, HIV must reach the nucleus before it can really set up headquarters and produce more virus. But virtually nothing was known about how it got there."
The researchers used a custom-designed microscope that enabled them to scrutinise living cells in three dimensions. They observed the virus skimming along microtubules, the molecular tent poles, which form the backbone of the cell's internal skeleton.
"We see the green lights gliding along in a straight line and moving towards the nucleus fairly rapidly. This led us to believe the virus might be attaching to something solid, rather than diffusing through the cytoplasm or being transported in [fluid-filled sacs]," Professor Hope said.
The next stage is to see if this can be blocked. "If we could obstruct this step, we'd have a good candidate for a drug to block HIV infection," he said.Reuse content