Researchers at the University of Chicago, using fluorescent proteins and time-lapse photography, have documented for the first time HIV's slow path in penetrating human immune cells, BBC News reports. The pictures offer proof that the virus uses natural cellular machinery to move from the cell membrane into the nucleus. HIV was shown to attach to a cell protein called dyenin to travel through a series of tiny microtubules from the cell membrane into the center of the cell. The microtubules lead all the way to the cell's nucleus where HIV inserts its own genetic material, effectively turning the cell into a factory that will make copies of the virus.
Time-lapse photographs were taken under the microscope at 15-second intervals to reveal the virus's steady--but sometimes haphazard--progress toward the center of the cell. "They don't make a beeline for the nucleus," said Prof. David McDonald. "Their progress is somewhat halting. They appear to jump from one microtubule to another, moving in a jagged path, even sometimes moving backward, but they eventually reach their destination." The pictures can be seen in the Journal of Cell Biology.
The researchers hope their findings will help other scientists gain a better understanding of how HIV invades immune system cells and offer up new targets for treatments to slow HIV infection, including compounds that aim to prevent HIV from linking with the dyenin proteins or travel freely through cellular microtubules.