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A nationwide team of researchers, led by scientists at �����г���Ƶ of Utah �����г���Ƶ and The Rockefeller �����г���Ƶ, has determined how a genetic mutation found in mice and monkeys interferes with viruses such as HIV and Ebola. They say the finding could eventually lead to the development of medical interventions in humans 

The gene, called retroCHMP3, encodes an altered protein that disrupts the ability of certain viruses to exit an infected cell and prevents it from going on to infect other cells.

Normally, some viruses encase themselves in cell membranes and then make an exit by budding off from the host cell. RetroCHMP3 delays that process long enough that the virus can no longer escape.

“This was an unexpected discovery,” says  senior author of the study and an evolutionary geneticist in the Department of Human Genetics at U of U �����г���Ƶ. “We were surprised that slowing down our cell biology just a little bit throws virus replication off its game.”

The study appears online Sept. 30 in advance of the Oct. 14 issue of 

RetroCHMP3 originated as a duplicated copy of a gene called charged multivesicular body protein 3, or CHMP3. While some monkeys, mice, and other animals have retroCHMP3 or other variants, humans only have the original CHMP3.

In humans and other creatures, CHMP3 is well known for playing a key part of a role in cellular processes that are vital for maintaining cellular membrane integrity, intercellular signaling, and cell division.

HIV and certain other viruses hijack this pathway to bud off from the cellular membrane and infect other cells. Based on their research, Elde and his colleagues suspected that the duplications of CHMP3 they discovered in primates and mice blocked this from happening as protection against viruses like HIV and other viral diseases.

Building on this notion, Elde and other scientists began exploring whether variants of retroCHMP3 might work as an antiviral. In laboratory experiments conducted elsewhere, a shorter, altered version of human CHMP3 successfully prevented HIV from budding off cells. But there was a glitch: the modified protein also disrupted important cellular functions, causing the cells to die. 

Unlike the other researchers, Elde and his colleagues at U of U �����г���Ƶ had naturally occurring variants of CHMP3 from other animals in hand. So, working in collaboration with researchers Sanford Simon at The Rockefeller �����г���Ƶ, along with Phuong Tieu Schmitt and Anthony Schmitt at Pennsylvania State �����г���Ƶ, they tried a different approach.

Using genetic tools, they coaxed human cells to produce the version of retroCHMP3 found in squirrel monkeys. Then, they infected the cells with HIV and found that the virus had difficulty budding off from the cells, essentially stopping them in their tracks. And this occurred without disrupting metabolic signaling or related cellular functions that can cause cell death.