title: De novo [PSI+] prion formation involves multiple pathways to form infectious oligomers.
abstract: Prion and other neurodegenerative diseases are associated with misfolded protein assemblies called amyloid. Research has begun to uncover common mechanisms underlying transmission of amyloids, yet how amyloids form in vivo is still unclear. Here, we take advantage of the yeast prion, [PSI+], to uncover the early steps of amyloid formation in vivo. [PSI+] is the prion form of the Sup35 protein. While [PSI+] formation is quite rare, the prion can be greatly induced by overexpression of the prion domain of the Sup35 protein. This de novo induction of [PSI+] shows the appearance of fluorescent cytoplasmic rings when the prion domain is fused with GFP. Our current work shows that de novo induction is more complex than previously thought. Using 4D live cell imaging, we observed that fluorescent structures are formed by four different pathways to yield [PSI+] cells. Biochemical analysis of de novo induced cultures indicates that newly formed SDS resistant oligomers change in size over time and lysates made from de novo induced cultures are able to convert [psi-] cells to [PSI+] cells. Taken together, our findings suggest that newly formed prion oligomers are infectious.
authors.affiliation: Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA.
authors.forename: Jaya
authors.initials: J
authors.lastname: Sharma
authors.affiliation: Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA.
authors.forename: Brett T
authors.initials: BT
authors.lastname: Wisniewski
authors.affiliation: Department of Mathematics, Statistics and Computer Science, Marquette University, Milwaukee, WI, 53201, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Paulson
authors.affiliation: Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA.
authors.forename: Joanna O
authors.initials: JO
authors.lastname: Obaoye
authors.affiliation: Department of Mathematics, Statistics and Computer Science, Marquette University, Milwaukee, WI, 53201, USA.
authors.forename: Stephen J
authors.identifier: 0000-0002-2975-950X
authors.initials: SJ
authors.lastname: Merrill
authors.affiliation: Department of Biological Sciences, Marquette University, Milwaukee, WI, 53201, USA. anita.manogaran@marquette.edu.
authors.forename: Anita L
authors.identifier: 0000-0003-0844-1479
authors.initials: AL
authors.lastname: Manogaran
mesh_terms: D003593:Cytoplasm / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D010454:Peptide Termination Factors / Q000737:chemistry / Q000378:metabolism*; D011328:Prions / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
chemical_list: D010454:Peptide Termination Factors; D011328:Prions; C068068:SUP35 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D012967:Sodium Dodecyl Sulfate