GAINESVILLE, Fla. -- University of Florida researchers have identified specific human genes targeted by a virus believed to cause Kaposis sarcoma, a rare form of cancer associated with AIDS and with organ transplants that causes patches of red or purple tissue to grow under peoples skin.

Writing today (May 11) in PLOS Pathogens, the scientists are the first to name human genes that are actually hijacked by a virus wielding minimolecules called microRNAs.

Apparently the viral microRNAs silence genes known to influence growth of blood vessels and suppress tumor cells. Scientists believe that with the regulatory genes sidelined, blood vessel growth runs rampant, resulting in the typical markings of Kaposis sarcoma.

"The hallmarks of Kaposis sarcoma are red spots full of blood vessels on the necks, arms and legs of patients," said Rolf Renne, Ph.D., an associate professor of molecular genetics and microbiology at the College of Medicine and a member of the UF Shands Cancer Center and the UF Genetics Institute. "We think that the tumor virus is using microRNAs to make sure infected cells are well nourished and protected from the human immune system."

Thought to be little more than cellular debris less than a decade ago, microRNAs are short chemical strands that strategically silence gene activity by binding to RNA within cells. They play a role in healthy development no one with a complete set of fingers and toes would want their genes to keep adding new digits and they evidently may be involved in the onset of some diseases, including cancer.

Now it seems that even foreign microRNA has a say in human health.

In an effort to identify human gene targets, UF scientists equipped cultured human cells with just 10 genes from the Kaposis sarcoma virus, thus endowing human cells with the ability to produce viral microRNA. Scientists then screened the more than 30,000 genes that exist within human cells and found
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Contact: Johanna Dehlinger
press@plos.org
415-624-1204
Public Library of Science
10-May-2007