Effects Of Metal Salts With Chloride And Sulfate Anion On Yeast Prion [PSI~+] Inducting

[PSI⁺] is an epigenetic modifier of nonsense suppression in yeast and is consideras a prion state of Sup35p that functions as a translation termination factor.The research shows that yeast prion switching in response to environmental stressthat can inducing [psi^-] to [PSI⁺] in cellular, they will appearance of the de novoformation of [PSI⁺] phenotypes, such as oxidative stress or high salt concentration.In our reseach, we studied the effect of metal salts with chloride and sulfate anionsstress in cell culture model of yeast prion. Following three contents:First, we use the strain through them to the conditions under difference the eightsalts with Cl^-/SO₄^2-, then was observed their phenotypes and growth on1/2YPD andSD-Ade. The results showed that eight salts conditions also could induced thecolotation of [psi^-] colonies shifted from red to white on1/2YPD mudium. All of thede nove [PSI⁺] conlonies effects of CuCl₂, CuSO₄, FeCl₂, FeSO₄, ZnCl₂and ZnSO₄did growth on SD-Ade as wild type of [PSI⁺], but some colonies appeared very poor[PSI⁺] phenotype under the conditionds of MnCl₂and MnSO₄.Second,[PSI⁺] cells were exposed to guanidine hydrochloride （GuHCl）, it thatcould be cured to [psi^-] cells. We demonstrated that most of the de nove [PSI⁺] couldnot be cured with GuHCl. Normally, plasmid carrying Sup35p-GFP was transformedinto yeast cells （[GPSI⁺]）, fluorescent assay showed that fluorescent foci in [PSI⁺]cells, and [psi^-] cells are soluble. these de nove [PSI⁺] cell could not appearaedfluorescent foci in FeCl₂, FeSO₄, ZnCl₂or ZnSO₄,other than in CuCl₂or MnCl₂conditions. Otherwise, we founded that guanidine hydrochloride was unable to cureyeast prion [PSI⁺] when cell division was suppressed by hydroxylurea too.Third, quantitative studies were carried on status changes of Sup35p aggregationunder different salt conditions with MnCl₂.We found that it could also induceSup35p-GFP aggregation but the aggregation does not depend on the presence ofMnCl₂,that the size of aggregation between polymers and monomers.To sum up, it could be concluded that nonsense suppression could be caused byhigh concentration of metal salts with Cl^-/SO₄^2-, the de nove [PSI⁺] showed the phenomenon of false-positive. All the results mentioned above indicated that themechanism of the de novo formation of yeast prion [PSI⁺] was complicated, andthese may shed light on the de novo formation of yeast prion as a previous researchand be a complement to our anti-prion drug screening model.