Gene Neighbors May Have Taken Turns Battling Retrovirues

(Ivanhoe Newswire) -- A gene called TRIM5 has been doing battle with retroviruses like HIV for years.  But new research shows that TRIM5 has a next door neighbor called TRIM22 may have been in the battle as well.

The research was done Sara Sawyer, Ph.D., a postdoctoral research fellow in the Basic Sciences Division at Fred Hutchinson Cancer Center. Sawyer worked with colleague and senior author Harmit Singh Malik, Ph.D. and co-author Michael Emerman, Ph.D of the Center’s Human Biology division.

Their findings, published in the open-access Journal PLoS Pathogens, show that both TRIM5 and TRIM22 show the hallmarks of positive selection needed to defeat new retroviral invasions. But because the 2 genes are so close to each other, the positive selection has been taking place in either TRIM5 or TRIM22, but not both which suggests they’ve been taking turns defending against retroviruses.

“The identification of novel antiviral genes is important to understanding the genetic basis for differential human susceptibility to viral diseases,” said Sawyer.

The study also suggests that unlike TRIM4 TRIM22 did not have antiviral activity against any modern viruses tested. “We are at an interesting point in this kind of research,” Emerman said. “Instead of looking at which unknown antiviral gene protected against a given virus, we now need to ask which unknown virus may have been defeated by a given candidate antiviral gene. It is possible that this virus no longer exists today, but may have only existed in our evolutionary past.”

Said Marki, “This research was conducted via computer analysis and in tissue-culture cells and has not yet been tested in model organisms. Nonetheless, the evolutionary means to identify other potential antiviral TRIM genes in the human genome may identify novel candidates for therapeutic intervention,”

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SOURCE: PLoS Pathogens Open-access Journal Dec. 21, 2007