June 15 – Your Prion Eyes

Today’s factismal: Genes to protect against prions have been seen in most human populations.

In Papua New Guinea, there is a tribe known as the Fore. They are noted for having strong family groups and for an unusual practice that strengthens the family bond; whenever a family member would die, he would be carved up and eaten at the funeral as a way pf preserving the family bond. Unfortunately for the Fore, more than family bonds gets preserved that way. A misshaped protein known as a prion also gets passed along. This protein tricks the victim’s cells into producing more of the prions; for reasons that still aren’t clear, the prions get concentrated in the brain where they cause spongiform encephalopathy (medicine-speak for “gaping holes eat into the brain”). As a result, the victim would slowly lose control of his limbs and speech center, causing him to shiver uncontrollably and to burst out into inappropriate laughter. It was this last symptom that gave the disease its names Kuru (“the shaking disease”) and “the laughing disease”.

A typical prion (Image courtesy NIH)

A typical prion
(Image courtesy NIH)

But what is fascinating about kuru is the way that the Fore responded to it. At its height, kuru killed about 2% of the tribe each year. But some people never got the disease, thanks to a random mutation that had probably been around for centuries before. Known as V127, this gene prevents the prion from being formed. Researchers have found that tribesmen with one copy of the gene never got kuru and those with two copies of the gene were immune against all known forms of human prion disease as well. Interestingly, similar genes have been identified in groups around the world, implying that cannibalism was found in just about every group at one time or another.

Prions in E. coli (Image courtesy NIH)

Prions in E. coli
(Image courtesy NIH)

Another thing that is found in just about every group of humans (except straight party ticket voters) is curiosity. And there are a lot of scientists who are curious about how proteins fold and what happens when the way that they fold changes. Do we get a new disease? A new eye color? A new way of using carbon dioxide? We don’t know yet, but you can help us learn! By playing the game Fold It, you can discover how proteins fold and help scientists discover more about proteins. To learn more, head to:
http://fold.it/portal/

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