Creating a protein-based element of inheritance

Proteins capable of self-perpetuating changes in conformation and function (known as prions) can serve as genetic elements. To test whether novel prio ns could be created by recombinant methods, a yeast prion determinant was f used to the rat glucocorticoid receptor. The fusion protein existed in diff erent heritable functional states, switched between states at a Low spontan eous rate, and could be induced to switch by experimental manipulations. Th e complete change in phenotype achieved by transferring a prion determinant from one protein to another confirms the protein-only nature of prion inhe ritance and establishes a mechanism for engineering heritable changes in ph enotype that should be broadly applicable.