Yeast [PSI+] "prions" that are crosstransmissible and susceptible beyond a species barrier through a quasi-prion state.
The yeast [PSI(+)] element represents an aggregated form of release factor Sup35p and is inherited by a prion mechanism. A "species barrier" prevents crosstransmission of the [PSI(+)] state between heterotypic Sup35p "prions." Kluyveromyces lactis and Yarrowia lipolytica Sup35 proteins, however, show interspecies [PSI(+)] transmissibility and susceptibility and a high spontaneous propagation rate. Cross-seeding was visualized by coaggregation of differential fluorescence probes fused to heterotypic Sup35 proteins. This coaggregation state, referred to as a "quasi-prion" state, can be stably maintained as a heritable [PSI(+)] element composed of heterologous Sup35 proteins. K. lactis Sup35p was capable of forming [PSI(+)] elements not only in S. cerevisiae but in K. lactis. These two Sup35 proteins contain unique multiple imperfect oligopeptide repeats responsible for crosstransmission and high spontaneous propagation of novel [PSI(+)] elements.
Nakayashiki
T
T
Department of Basic Medical Sciences and, Institute of Medical Science, University of Tokyo, 108-8639, Tokyo, Japan. nak@ims.u-tokyo.ac.jp
Ebihara
K
K
Bannai
H
H
Nakamura
Y
Y
D002175:Candida / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D005800:Genes, Fungal / Q000502:physiology*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism; D007716:Kluyveromyces; D008164:Luminescent Proteins / Q000235:genetics; D008561:Membrane Fusion; D008969:Molecular Sequence Data; D010454:Peptide Termination Factors; D011328:Prions / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013045:Species Specificity; D014170:Transformation, Genetic; D015003:Yeasts / Q000378:metabolism*; D020068:Zygosaccharomyces / Q000378:metabolism
D005656:Fungal Proteins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins