Cytoduction and Plasmiduction in Yeast.

Cytoduction, and a related technique referred to as plasmiduction, have facilitated substantial advancements in the field of yeast prion biology by providing a streamlined method of transferring prions from one yeast strain to another. Prions are cytoplasmic elements consisting of aggregated misfolded proteins, and as such, they exhibit non-Mendelian patterns of inheritance. While prion transfer through mating and sporulation, or through protein transformation, is possible, these approaches yield non-isogenic strains or are technically complex, respectively. Cytoduction is a mating-based technique that takes advantage of a kar1 mutation with impaired nuclear fusion (karyogamy). It is a straightforward method for introducing a prion to any yeast strain (referred to as the recipient) by mating it with a donor strain containing the prion of interest. The only absolute requirement is that one of these two strains (donor or recipient) must carry the kar1-1 mutation to limit nuclear fusion. The resulting cytoductant contains the original nucleus of the recipient strain, but a cytoplasm reflecting a mix of all elements from the donor and the recipient. Modifications to the basic cytoduction strategy provide several options for successful cytoduction, including when working with slow growing or respiratory deficient strains. A significant advantage of the plasmiduction protocol presented is the ability to transfer a plasmid encoding a fluorescently tagged version of the prion protein, which allows for the direct verification of the prion state through visual protein aggregates. Graphic abstract: Transfer of Yeast Cytoplasmic Elements such as Prions using Cytoduction.