Moo.
Prions are the pariahs of the protein world. They lurk behind bovine spongiform encephalopathy, chronic wasting disease, and Creutzfeldt–Jakob disease, causing horrific symptoms and almost always leading to the death of the infected. Proteins gone bad, you might say.
Scientists always suspected prion proteins—the precursors to prions themselves—have a useful role to play. That function, though, eluded discovery until yesterday. Researchers injected zebra fish embryos with morpholinos, molecules that stem the production of prion proteins, and lo and behold, the embryos soon petered out. Prion proteins, they think, are the tie that binds embryonic cells together. Without close contact, the cells cannot communicate properly, and the cells fail to differentiate.
