Sunday, May 1, 2016

Researcher finds prions in plants

Prions may be lurking in plants.

Prions are held responsible for Bovine Spongiform Encephalopathy (BSE, or mad cow’s disease) and deadly Kreutsfeldt-Jacob disease in humans.

A research team led by Susan Lindquist, a biologist at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, say they found a section of protein in thale cress (Arabidopsis) that behaves like a prion when it is inserted into yeast.

More research is required to determine whether they are like prions that attack the brains of mammals.

In plants, the protein is called Luminidependens (LD), and it is normally involved in responding to daylight and controlling flowering time. 

When a part of the LD gene is inserted into yeast, it produces a protein that does not fold up normally, and which spreads this misfolded state to proteins around it in a domino effect that causes aggregates or clumps. 

Later generations of yeast cells inherit the effect: their versions of the protein also misfold.

This does not mean that plants definitely have prion-like proteins, says Lindquist; but she thinks that it is likely. 

“I’d be surprised if they weren’t there,” she says. 

To prove it, researchers would need to grind up a plant and see whether they could find a protein such as LD in several different folded states, as well as show that any potential prion caused a misfolding cascade when added to a test-tube of protein. 

Lindquist adds that because she’s not a plant scientist — her focus is on using yeast to investigate prions — she hasn’t tried these experiments. 

The study appeared Apr. 25 in the Proceedings of the National Academy of Sciences.