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Posted 05.18.06

MU Researcher Uses New Grant to Uncover HIV 'Assembly' Secrets

Marc Johnson Received More than $250,000 for the Research Project

COLUMBIA, Mo. -- More than 40 million people worldwide are infected with HIV, the virus that causes AIDS. While current therapies are able to repress the virus if caught early enough, scientists are still working on a cure for the deadly disease. One MU researcher has developed a unique molecular tracking system that peers into cells, uncovering how the virus assembles its "parts" to make more virus particles and spread the infection.

Marc Johnson, an assistant professor of microbiology and immunology and winner of a 2006 Beckman Foundation Young Investigator award, said that if scientists can determine the assembly mechanisms of the virus, or how the virus duplicates itself, they may be able to develop a type of therapy that could potentially stop the virus from spreading throughout the body. Johnson is using fluorescence microscopy coupled with scanning electron microscopy to watch how the virus is assembled inside living cells.

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"Currently, scientists have been using fluorescence microscopy as an imaging system to see the different particles," Johnson said. "The problem is that the resolution is nowhere near the detail we need to view individual parts of a virus. This new technique will allow us to see much more detail than before and might reveal some of the virus' secrets."

HIV contains three major genes that must combine to form the virus. When HIV infects a cell, it begins the process of replicating itself by producing these three genes. Once the genes are created, they assemble to form the virus particles and then exit the cell to spread throughout the body. While current therapies prevent infection of other cells by blocking the viruses that are released, they do have some very harmful side effects. In addition, even though the viruses are unable to infect other cells, there are infected cells in the body that continue to produce more virus particles and can stay dormant in the body for years.

Johnson reported his recent findings in a paper published in October in the Proceedings of the National Academies of Science. In addition to the scanning electron microscopy technique, Johnson also is working with fellow researcher Deyu Fang, assistant professor of otolaryngology, who has developed a way to tag the virus parts before they assemble. While the tag for the virus parts is a type of fluorescent tag, it does not illuminate until the virus parts are very close together. This unique aspect will allow the Mizzou researchers to identify specific areas of the cell where the virus assembles.

"Different locations have been implemented in the viral assembly process, but we just don't know exactly where any of this process takes place," Johnson said. "The long term outlook is to see if we can find a chemical that will prevent these proteins from ever assembling into the virus."



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