Tag: prions

Study: Prions Can Be Helpful Engine of Evolution, Rather than Cause of Disease

By Sarah Zhang | February 17, 2012 1:18 pm

spacing is important
Yeast under a microscope.

What’s the News: Prions get a bad name—the very word is a portmanteau of “protein” and “infection,” which suggests that they’re up to no good. And there’s obviously some truth to this: Prions are a type of protein that have alternative folded forms, and if they aggregate into insoluble clumps, they can cause problems like mad cow disease. But prions might also be a key part of evolution. A new survey published in Nature found prions in 1/3 of yeast strains, and 40% of the traits they conferred were beneficial.

Read More

CATEGORIZED UNDER: Living World, Top Posts

In Flies, a Prion-Like Protein Helps Maintain Long-Term Memories

By Sarah Zhang | February 8, 2012 8:08 am

spacing is important

What’s the News: When prions or amyloids make the news, it’s usually because they cause mad cow disease or Alzheimer’sprions, after all, cause any proteins they touch to become as misfolded as they are, and amyloids, which are large clumps of wadded-together proteins, can jam the workings of cells.

But a new study in Cell suggests that a prion-like protein that forms amyloids has a normal, vital function in the brain. Far from being a memory destroyer, this protein, called CPEB, is necessary for long-term memory in fruit flies.

Read More

Mad Cow Disease Can Go Airborne? Yes, but Don't Panic

By Eliza Strickland | January 14, 2011 3:43 pm

It sounds like the start of a science fiction movie: a lethal brain disease that goes airborne. But while scientists have indeed found that the prions responsible for mad cow disease and other neurological ailments can float on the breeze and infect those who inhale, they say there’s no reason to barricade your gas-masked family inside your house.

Prions are misfolded proteins that cause brain degeneration; in mad cow disease they’ve typically been transmitted when one cow eats the infected brain or spinal cord tissue of another (something that agricultural institutions now agree shouldn’t happen in the first place). Other prion diseases, including the human variant Creutzfeldt-Jakob disease, are also passed along through body fluids and tissue. But for a new study published in PLoS Pathogens, researchers decided to find out if airborne prions could serve as infectious agents.

The short answer: Yes.

Read More

When Prions Do Good: Properly Folded Proteins May Protect Nerve Cells

By Smriti Rao | January 25, 2010 6:47 pm

main.2010.prion_protein_storyFor years, prions have been known only as a serious danger to animal and human health. These misfolded brain proteins have been linked to fatal diseases–like mad cow disease in cattle and the deadly variant Creutzfeldt-Jakob disease in humans. But apart from causing these diseases, scientists puzzled for years about the exact function of a properly folded prion protein.

A new study in Nature Neuroscience may have some answers. After 20 years of research, an international team of neuroscientists reports that, in mammals, the mysterious proteins help to maintain the myelin sheath that protects the body’s nerves [Nature News]. A healthy sheath is necessary for nerve cells to transmit impulses rapidly.

Read More

CATEGORIZED UNDER: Health & Medicine, Mind & Brain
MORE ABOUT: mad cow disease, prions

Who Needs DNA? Prions Evolve Without It

By Andrew Moseman | January 5, 2010 1:41 pm

prionsFor evolution to take place, you need DNA or RNA to change through mutation, providing the variations for natural selection to select. Right? Well, it may be more complicated than that. A new study suggests an exception: prions, the infectious protein bits that can cause degenerative brain diseases like mad cow disease. In a paper in Science, researchers document these lifeless structures evolving, despite the fact that they lack any DNA or RNA.

Study leader Charles Weissmann and his team transferred prions from brain cells to other kinds of cells and watched as certain members of the prion population adapted to the new environment and took over, out-competing their brethren. When he transferred the prions back to brain cells, the ones most adapted to brain living got the upper hand and increased in number as they out-competed the prions that had adapted to other cells. Weissmann argues that this shows Darwinian evolution can go even further than we thought: “In viruses, mutation is linked to changes in nucleic acid sequence that leads to resistance. Now, this adaptability has moved one level down- to prions and protein folding – and it’s clear that you do not need nucleic acid (DNA or RNA) for the process of evolution” [BBC News].

Read More

CATEGORIZED UNDER: Health & Medicine, Living World

New Guinean Cannibals Evolved Resistance To Mad Cow-Like Disease

By Andrew Moseman | November 19, 2009 3:24 pm

Fore220Members of a tribe in Papua New Guinea has evolved resistance to a affliction similar to mad cow disease (called Creutzfeldt Jakob disease, or CJD, in people). How did they do it? Cannibalism, according to a study in the New England Journal of Medicine.

The Papua New Guinea variant is called kuru, and it was a disaster there. When members of the Fore people in Papua New Guinea died, others would eat the dead person’s brain during funeral rituals as a mark of respect. Kuru passed on in this way killed at least 2500 Fore in the 20th century until the cause was identified in the late 1950s and the practice halted [New Scientist].

The scientists compared DNA samples of about 3,000 living Fore people, some of whom had participated in the old rituals, to 152 samples of stored DNA from Fore that kuru killed. They looked at the genes for prions, ordinary brain proteins that take on a misfolded shape in prion disease such as CJD and kuru. They found a mutation called G127V that protected people from kuru. Only people who ate brains and survived have it, they found [Reuters].

The discovery excited scientists with the possibility of understanding and even treating other prion diseases, like CJD. And British neurologist John Hardy exemplified the scientific glee at seeing human evolution happen in such a short time. “It’s fantastic demonstration of natural selection… In Papua New Guinea kuru became the major cause of death, so there was a clear survival advantage and the selection pressure was enormous” [BBC News].

Related Content:
Discoblog: For Early Europeans, Cannibalism Was One Perk of Victory
Discoblog: Mad Cow Fears Keep Euro Sperm Out of U.S.
80beats: Female Tarantulas Devour Extra Suitors to Benefit Their Young

Image: D. Carleton Gajdusek

CATEGORIZED UNDER: Health & Medicine

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


80beats is DISCOVER's news aggregator, weaving together the choicest tidbits from the best articles covering the day's most compelling topics.

See More

Collapse bottom bar