a plus for prions

Prions—perhaps the most maligned members of the protein world, fingered for causing mad cow disease, among other things—turn out to play a positive role.

Scientists have suspected for years that the prion gene must have some usefulness for organisms; otherwise, why would they carry around this ticking time bomb? If the protein folds the wrong way, it clumps together and causes disease, and the misfolded proteins are infective, since they induce their normal neighbors to also misfold.

Now researchers have found a normal function for the prion gene: helping stem cells in bone marrow survive and divide.

Read more in the ScienceNOW article by Jennifer Couzin. Link