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MUNICH, GERMANY--The single virus, tagged with one fluorescent dye molecule, bumps against a living cell once, twice--up to five times--making contact for less than a second on each approach before the cell suddenly engulfs it. Only a fraction of all single viruses make it past the external cell membrane, new research suggests. But, once inside, the successful invading virus has a good chance of penetrating its target, the nucleus, within a few minutes.

Surprisingly, researchers report in the 30 November 2001 issue of the journal Science, key infection steps occur much faster than previously believed. Moreover, tubular structures might serve as pipelines for viruses, which perhaps ride piggyback on "motor proteins" to reach the nuclear area, where genetic expression occurs, promoting infection.

Such insights--illustrated in real-time movies created by scientists of the Ludwig-Maximilians-Universitt Mnchen--may set the stage for better anti-viral drugs, or for delivering gene-therapy medicines directly to the cell nucleus. "For the first time, we have been able to observe a single virus, labeled with only one dye molecule, on its infectious entry pathway into a living cell," explains researcher Christoph Bruchle, senior author on the Science paper, published with his University colleagues, Georg Seisenberger, Martin U. Ried, Thomas Endre, Hildegard Bning and Michael Hallek. "Labeling with only one dye molecule minimizes the distortion of virus-cell interactions. In addition, the single virus tracing technique shows us that infection happens much more rapidly than we previously assumed-within minutes, rather than hours."

To study different stages of infection pathways, so far researchers typically have used a conventional techniq
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Contact: Ginger Pinholster
gpinhols@aaas.org
202-326-6421
American Association for the Advancement of Science
29-Nov-2001