Study provides new details of 'the birth o...( BOSTON - With sinis...)

BOSTON - With sinister efficiency, retroviruses such as HIV use only a small portion of their genetic programming to steal away from the cell where they were born and infect other cells. A study published this week by scientists at Dana-Farber Cancer Institute provides new details of how retroviruses make their escape and cloak themselves in the cell's membrane to avoid attack from the body's immune system.

The study, published in the November 21 issue of the Proceedings of the National Academy of Sciences, is one of three in the journal to focus on the mechanics of viral departure from cells - research that may one day lead to new techniques for arresting the process and preventing the spread of viral infection within the body.

"The last stages of the formation of viruses within cells and the process by which viruses leave cells are among the least understood aspects of the viral life cycle," says senior author Heinrich Gttlinger, M.D., of Dana-Farber and Harvard Medical School. "Our research sheds light on previously unknown aspects of this process and on the mechanisms that cause a virus to assemble in the first place."

The Dana-Farber study spotlights the function of ubiquitins, which help viruses break free from the cells where they were born, and on a viral segment known as the "late domain," which is in a protein called Gag. The domain, as its name suggests, comes into play late in the process by which viruses are assembled inside cells, just before they leave to infect other cells.

The process works like this: After infecting a cell, a virus takes over a cell's reproductive machinery to produce thousands of copies of itself. The not-yet-fully-assembled viruses - really just packets of RNA at this point - congregate inside the cell membrane like protesters pressing against a police barricade. The cell membrane begins to bulge and eventually forms a "bubble" that seals the viral RNA off from the rest of th
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Contact: Todd Ringler
todd_ringler@dfci.harvard.edu
617-632-5357
Dana-Farber Cancer Institute
20-Nov-2000