US researchers have found that one prion protein can cause the formation of other, different types of prions, a finding that has implications for the way Creutzfeld Jakob disease (CJD) develops in humans.
Using a yeast model, the researchers devised a screening test to study the interaction between prions and to help identify new, previously unheard of prions.
Up to now, it was thought that each type of prion was a distinct entity and that a type 1 prion, for instance, would only change a type 1 protein into a prion.
However, the current study found that the presence of one type of prion enhanced the possibility of the spontaneous development of other types. These findings, say the researchers, may help solve the question of how prions first appear. Noting that most cases of CJD appear to have no specific origin, the researchers suggest that more attention needs to be paid to the other types of prions that may occur in mammals. The presence of these prions may explain why the 'mad cow' prion seems to appear spontaneously in a population (Cell, 2001; 106: 171-82).