Propagation of the [PIN+] prion by fragments of Rnq1 fused to GFP.

Prions are viewed as enigmatic infectious entities whose genetic properties are enciphered solely in an array of self-propagating protein aggregate conformations. Rnq1, a yeast protein with yet unknown function, forms a prion named [PIN+] for its ability to facilitate the de novo induction of another prion, [PSI+]. Here we investigate a set of RNQ1 truncations that were designed to cover major Rnq1 sequence elements similar to those important for the propagation of other yeast prions: a region rich in asparagines and glutamines and several types of oligopeptide repeats.

Visualization of aggregation of the Rnq1 prion domain and cross-seeding interactions with Sup35NM.

Factors triggering the de novo appearance of prions are still poorly understood. In yeast, the appearance of one prion, [PSI(+)], is enhanced by the presence of another prion, [PIN(+)]. The [PSI(+)] and [PIN(+)] prion-forming proteins are, respectively, the translational termination factor Sup35 and the yet poorly characterized Rnq1 protein that is rich in glutamines and asparagines.