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Factors triggering the de novo appearance of prions are still poorly understood. In yeast, the appearance of one prion, [PSI+], is enhanced by the presence of another prion, [PIN+]. The [PSI+] and [PIN+] prion-forming proteins are, respectively, the translational termination factor Sup35 and the yet poorly characterized Rnq1 protein that is rich in glutamines and asparagines. The prion domain of Rnq1 (RnqPD) polymerizes more readily in vitro than the full-length protein. As is typical for amyloidogenic proteins, the reaction begins with a lag phase, followed by exponential growth. Seeding with pre-formed aggregates significantly shortens the lag. A generic antibody against pre-amyloid oligomer inhibits the unseeded but not the self-seeded reaction. As revealed by electron microscopy, RnqPD polymerizes predominantly into spherical species that eventually agglomerate. We observed infrequent fiber-like structures in samples taken at 4 h of polymerization, but in overnight samples SDS treatment was required to reveal fibers among agglomerates. Polymerization reactions in which RnqPD and the prion domain of Sup35 (Sup35NM) cross-seed each other proceeded with a shortened lag that only depends weakly on the protein concentration. Cross-seeded Sup35NM fibers appear to sprout from globular RnqPD aggregates as seen by electron microscopy. RnqPD spherical aggregates appear to associate with and, later occlude, Sup35NM seed fibers. Our kinetic and morphological analyses suggest that, upon cross-seeding, the aggregate provides the surface on which oligomers of the heterologous protein nucleate their subsequent amyloid formation. Factors triggering the de novo appearance of prions are still poorly understood. In yeast, the appearance of one prion, [PSI+], is enhanced by the presence of another prion, [PIN+]. The [PSI+] and [PIN+] prion-forming proteins are, respectively, the translational termination factor Sup35 and the yet poorly characterized Rnq1 protein that is rich in glutamines and asparagines. The prion domain of Rnq1 (RnqPD) polymerizes more readily in vitro than the full-length protein. As is typical for amyloidogenic proteins, the reaction begins with a lag phase, followed by exponential growth. Seeding with pre-formed aggregates significantly shortens the lag. A generic antibody against pre-amyloid oligomer inhibits the unseeded but not the self-seeded reaction. As revealed by electron microscopy, RnqPD polymerizes predominantly into spherical species that eventually agglomerate. We observed infrequent fiber-like structures in samples taken at 4 h of polymerization, but in overnight samples SDS treatment was required to reveal fibers among agglomerates. Polymerization reactions in which RnqPD and the prion domain of Sup35 (Sup35NM) cross-seed each other proceeded with a shortened lag that only depends weakly on the protein concentration. Cross-seeded Sup35NM fibers appear to sprout from globular RnqPD aggregates as seen by electron microscopy. RnqPD spherical aggregates appear to associate with and, later occlude, Sup35NM seed fibers. Our kinetic and morphological analyses suggest that, upon cross-seeding, the aggregate provides the surface on which oligomers of the heterologous protein nucleate their subsequent amyloid formation. Prions are currently viewed as proteinaceous genetic elements because of their potential to encode, propagate, and discretely modify phenotypes produced by an infectious alternative conformational state of the prion protein (1Wickner R.B. Edskes H.K. Ross E.D. Pierce M.M. Baxa U. Brachmann A. Shewmaker F. Annu. Rev. Genet. 2004; 38: 681-707Crossref PubMed Scopus (72) Google Scholar). In this state, proteins form amyloid aggregates characterized by a rigid structure that is stabilized by inter β-sheet bonds (2Ross E.D. Minton A. Wickner R.B. Nat. Cell Biol. 2005; 7: 1039-1044Crossref PubMed Scopus (114) Google Scholar). These aggregates can convert molecules of the prion-forming protein from the normal conformation into the prion form. Propagation of the prion state in vivo is based upon fragmentation of already formed aggregates that results in multiplication of prion seeds. In mammals, the prion PrPSc is the causative agent of a series of neurodegenerative disorders, e.g. Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy, scrapie of sheep, etc. (for review see Ref. 3Prusiner S.B. Proc. Natl. Acad. Sci. U. S. A. 1998; 95: 13363-13383Crossref PubMed Scopus (5168) Google Scholar). Several prions have been characterized in the yeast Saccharomyces cerevisiae (for review see Refs. 4Osherovich L.Z. Weissman J.S. Dev. Cell. 2002; 2: 143-151Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar and 5Wickner R.B. Liebman S.W. Saupe S.J. Prusiner S.B. Prion Biology and Diseases. 2nd Ed. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY2004: 305-372Google Scholar), and a growing body of evidence suggests that there are interactions between them (for review see Ref. 6Derkatch I.L. Liebman S.W. Chernoff Y.O. Protein Based Inheritance. Landes Bioscience, Georgetown, TX2006Google Scholar). These interactions range from the ability of one prion to facilitate the appearance of another to incompatibility between some (7Derkatch I.L. Bradley M.E. Zhou P. Chernoff Y.O. Liebman S.W. Genetics. 1997; 147: 507-519Crossref PubMed Google Scholar, 8Schwimmer C. Masison D.C. Mol. Cell. Biol. 2002; 22: 3590-3598Crossref PubMed Scopus (157) Google Scholar, 9Bradley M.E. Liebman S.W. Genetics. 2003; 165: 1675-1685Crossref PubMed Google Scholar). Here we focus on two yeast prions, [PSI+] and [PIN+], as a model for prion-prion interactions. [PSI+] is composed of the alternatively folded translational termination factor Sup35 (10Ter-Avanesyan M.D. Dagkesamanskaya A.R. Kushnirov V.V. Smirnov V.N. Genetics. 1994; 137: 671-676Crossref PubMed Google Scholar, 11Zhouravleva G. Frolova L. Le Goff X. Guellec R.Le Inge-Vechtomov S. Kisselev L. Philippe M. EMBO J. 1995; 14: 4065-4072Crossref PubMed Scopus (523) Google Scholar) and is characterized by an increased level of readthrough of stop codons (nonsense suppression) because of the sequestration of Sup35 into prion aggregates (12Paushkin S.V. Kushnirov V.V. Smirnov V.N. Ter-Avanesyan M.D. EMBO J. 1996; 15: 3127-3134Crossref PubMed Scopus (470) Google Scholar). A Sup35 fragment spanning amino acids 1–253 (Sup35NM) 3The abbreviations used are: Sup35NM, region encompassing the N-terminal and middle domains of the yeast Sup35 protein (amino acids 1–254); TEM, transmission electron microscopy; ThT, thioflavin T; RnqPD, prion domain of the yeast Rnq1 protein (amino acids 132–405). forms fibers in vitro with sigmoidal kinetics in which rapid growth is preceded by a lag phase (13Glover J.R. Kowal A.S. Schirmer E.C. Patino M.M. Liu J.J. Lindquist S. Cell. 1997; 89: 811-819Abstract Full Text Full Text PDF PubMed Scopus (545) Google Scholar, 14DePace A.H. Santoso A. Hillner P. Weissman J.S. Cell. 1998; 93: 1241-1252Abstract Full Text Full Text PDF PubMed Scopus (334) Google Scholar). Such kinetics are typical of amyloidogenic proteins arguing that their polymerization is a nucleated process and that nucleation is the rate-limiting step (15Jarrett J.T. Lansbury Jr., P.T. Cell. 1993; 73: 1055-1058Abstract Full Text PDF PubMed Scopus (1933) Google Scholar). This model was developed further for Sup35NM by Serio et al. (16Serio T.R. Cashikar A.G. Kowal A.S. Sawicki G.J. Moslehi J.J. Serpell L. Arnsdorf M.F. Lindquist S.L. Science. 2000; 289: 1317-1321Crossref PubMed Scopus (831) Google Scholar) who showed that the nucleus forms within the context of an oligomer, although the involvement of an oligomeric intermediate was not supported in another study (17Collins S.R. Douglass A. Vale R.D. Weissman J.S. Plos Biol. 2004; 2: 1583-1590Crossref Scopus (422) Google Scholar). Unlike true amyloid fibers that appear after a lag, oligomers form soon after the resuspension of Sup35NM into an aqueous buffer (18Scheibel T. Bloom J. Lindquist S.L. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 2287-2292Crossref PubMed Scopus (81) Google Scholar). These in vitro made fibers (19Tanaka M. Chien P. Naber N. Cooke R. Weissman J.S. Nature. 2004; 428: 323-328Crossref PubMed Scopus (681) Google Scholar) as well as fibers of a shorter Sup35 fragment (20King C.Y. Diaz-Avalos R. Nature. 2004; 428: 319-323Crossref PubMed Scopus (420) Google Scholar) have been shown to be infectious as they convert the cells from [psi-]to[PSI+] upon transformation thus proving the protein-only hypothesis for the [PSI+] prion. In vivo, the appearance of [PSI+] can be induced by overproduction of Sup35NM in the presence of another prion, [PIN+] (7Derkatch I.L. Bradley M.E. Zhou P. Chernoff Y.O. Liebman S.W. Genetics. 1997; 147: 507-519Crossref PubMed Google Scholar). This prion is produced by a self-perpetuating aggregated form of Rnq1 (21Derkatch I.L. Bradley M.E. Hong J.Y. Liebman S.W. Cell. 2001; 106: 171-182Abstract Full Text Full Text PDF PubMed Scopus (491) Google Scholar), a protein whose function is not yet known. Rnq1 was discovered independently (22Sondheimer N. Lindquist S. Mol. Cell. 2000; 5: 163-172Abstract Full Text Full Text PDF PubMed Google Scholar) in a genome-wide screen in silico for proteins with homology to the Q/N-rich prion domains of the previously characterized yeast prion proteins Sup35NM and Ure2 (23Wickner R.B. Science. 1994; 264: 566-569Crossref PubMed Scopus (1089) Google Scholar) and was shown to be able to form a prion in vivo. The first studies of Rnq1 polymerization were done using a construct accidentally lacking the NNGNQN sequence at the C terminus (22Sondheimer N. Lindquist S. Mol. Cell. 2000; 5: 163-172Abstract Full Text Full Text PDF PubMed Google Scholar), which we refer to as altered Rnq1. It polymerized in vitro with a lag that could be shortened by self-seeding, and the presence of these Rnq1 aggregates enhanced polymerization of Sup35NM in vitro (24Derkatch I.L. Uptain S.M. Outeiro T.F. Krishnan R. Lindquist S.L. Liebman S.W. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 12934-12939Crossref PubMed Scopus (181) Google Scholar). This finding is one of the major arguments in favor of a cross-seeding mechanism postulated for the enhanced induction of [PSI+] in the presence of [PIN+]. Once formed, Sup35 and Rnq1 prion aggregates constitute separate structures in [PSI+][PIN+] yeast (25Bagriantsev S. Liebman S.W. J. Biol. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar), that cross-seeding is a required only for the of Sup35 polymerization which a more the between [PSI+] and [PIN+] are of the two each other M.E. Liebman S.W. Genetics. 2003; 165: 1675-1685Crossref PubMed Google Scholar). In the of Sup35 amyloid is upon Rnq1 aggregates Smirnov V.N. Kushnirov V.V. Ter-Avanesyan M.D. J. Biol. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar). interactions between Sup35 and Rnq1 at of and a in yeast prion Cross-seeded been for other amyloidogenic proteins, Protein Sci. 2004; PubMed Scopus Google Scholar), amyloid and P. R. J. Biol. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). In of cross-seeding, a of the lag in polymerization kinetics was observed and is to be to the of the heterologous seed at the rate-limiting step of the amyloid formation. Here we the of in vitro made aggregates formed by the prion domain of RnqPD in with the kinetics of their formation. Sup35NM and RnqPD aggregates can cross-seed each and kinetic analyses of the lag in reactions suggest that nucleation is the rate-limiting step in of aggregates by electron that cross-seeding a of Sup35NM and RnqPD, and this is further for the cross-seeding model of de novo prion Sup35NM, RnqPD, and full-length Rnq1 were in from the J. S. Protein 1994; 5: PubMed Scopus Google Scholar) the of S. and full-length Liebman S.W. J. Mol. Biol. Scholar). was in for at were by at for were on two in series the protein was to in on an an to of oligomeric and at of were done in a at The was The buffer was Protein are in the polymerization reactions of RnqPD and full-length Rnq1 the ability of the to the for Sup35NM polymerization reactions were done the in the kinetics of RnqPD polymerization, protein was to the first polymerization proceeded in the presence of the antibody of and from The of was to the reactions and was as S. Kushnirov V.V. Liebman S.W. PubMed Scopus Google Scholar). samples of protein were with SDS for on with and to a were with antibody (22Sondheimer N. Lindquist S. Mol. Cell. 2000; 5: 163-172Abstract Full Text Full Text PDF PubMed Google with the of a we used that, upon proteins as and this be used for a of an and RnqPD were polymerized in in for protein was by of the at of the used to fibers we the kinetics of polymerization in a and used to for samples in we the with the kinetics by aggregates made in a the as overnight aggregates made in a the morphological of reaction were to for were with in aqueous for and in analyses of of polymerization reaction were and with SDS for was to for at and in The SDS was on a As the was fibers were and in of fibers to were with in aqueous for and in was in and the of the on which the and was with fibers were in in for and normal for with antibody (22Sondheimer N. Lindquist S. Mol. Cell. 2000; 5: 163-172Abstract Full Text Full Text PDF PubMed Google in with for with with antibody in with for in in in for with with in aqueous for and with were on transmission electron at at a of and using a RnqPD and Rnq1 in study the of Rnq1 with to in prion-prion interactions in yeast, we on the domain of Rnq1 amino acids 132–405). RnqPD formed amyloid aggregates with sigmoidal kinetics as by A and with another study that used Liebman S.W. J. Mol. Biol. Scholar). The of unseeded RnqPD polymerization between and the of RnqPD aggregates that as polymerization the The lag was shortened in to the of seed and was only at of RnqPD and seed and The lag in unseeded reactions a be later in with the nucleated polymerization model for (15Jarrett J.T. Lansbury Jr., P.T. Cell. 1993; 73: 1055-1058Abstract Full Text PDF PubMed Scopus (1933) Google Scholar). A of the of the kinetics of RnqPD polymerization an but in in unseeded and self-seeded not This was followed by a the fibers cross-seed polymerization of RnqPD in kinetics of polymerization of RnqPD in the presence of of RnqPD aggregates the of Sup35NM aggregates was for in the unseeded reaction. of lag of RnqPD in unseeded and The was done in the presence of Sup35NM fibers for The of the is by the of the and the of the is by of of Sup35NM fibers on their ability to cross-seed RnqPD kinetics of polymerization of RnqPD in the presence of Sup35NM fibers that were for not as of the reaction with the with the of the lag of RnqPD polymerization on of Sup35NM As shown previously for Sup35 (17Collins S.R. Douglass A. Vale R.D. Weissman J.S. Plos Biol. 2004; 2: 1583-1590Crossref Scopus (422) Google Scholar), there was a of on the lag of the RnqPD polymerization reaction. RnqPD polymerization was in the reaction not in the reaction the required for e.g. polymerized with a lag Rnq1 polymerized with a lag that could be shortened by a of Rnq1 was to amyloid and the reaction to in the presence of amyloidogenic proteins and aggregate oligomeric that can be by a generic antibody R. Science. 2003; PubMed Scopus Google Scholar). This antibody is to the oligomeric than to in the amino and was shown previously to but not polymerization of Sup35NM J. Lindquist S. Science. 2004; PubMed Scopus Google Scholar). We on RnqPD, and the was to that for only unseeded polymerization was of prions is the SDS of prion for in vivo made prions of S.B. PubMed Scopus (157) Google Scholar), Sup35 Ter-Avanesyan M.D. Kushnirov V.V. J. Biol. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar), and Rnq1 (25Bagriantsev S. Liebman S.W. J. Biol. 2004; Full Text Full Text PDF PubMed Scopus Google Scholar). In vitro made Sup35NM fibers were shown previously to in SDS at into than the on S. Kushnirov V.V. Liebman S.W. PubMed Scopus Google Scholar). we the of SDS treatment on in vitro made RnqPD RnqPD were revealed polymerized RnqPD with SDS was In RnqPD with SDS as a and some oligomeric forms were observed in vitro made aggregates of full-length Rnq1 were of RnqPD the of aggregated RnqPD, we used RnqPD aggregates were made in in a reaction species could be seen in the samples that later in and in the samples This of RnqPD aggregates the The RnqPD of these aggregates was by using antibody and a antibody We could see structures with spherical species the samples but with a that the electron of these fibers was and of was to reveal structures were in the overnight samples after they by that they but were among the we RnqPD aggregates with SDS to In these fiber-like structures were observed in to the agglomerates. These fibers were in they could be and were composed of and one The of these fibers was in of which is than the of RnqPD aggregates from to that at some of the aggregates from of fibers that was by the SDS RnqPD Sup35NM aggregates of altered full-length Rnq1 were shown to the of Sup35NM polymerization in a as by at (24Derkatch I.L. Uptain S.M. Outeiro T.F. Krishnan R. Lindquist S.L. Liebman S.W. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 12934-12939Crossref PubMed Scopus (181) Google Scholar). Here we a kinetic of cross-seeding using RnqPD and a We that the of RnqPD aggregates is to the lag phase of Sup35NM polymerization in a but Sup35NM was polymerized in an reaction using the T.R. Cashikar A.G. Moslehi J.J. Kowal A.S. Lindquist S.L. PubMed Scopus Google Scholar). we the of the lag phase on the of Sup35NM at a in to the unseeded reaction. with (16Serio T.R. Cashikar A.G. Kowal A.S. Sawicki G.J. Moslehi J.J. Serpell L. Arnsdorf M.F. Lindquist S.L. Science. 2000; 289: 1317-1321Crossref PubMed Scopus (831) Google Scholar, S.R. Douglass A. Vale R.D. Weissman J.S. Plos Biol. 2004; 2: 1583-1590Crossref Scopus (422) Google Scholar), the of the lag of unseeded polymerization of weakly on the protein This was by the nucleated conformational to which an oligomeric intermediate to on the amyloidogenic conformation to (16Serio T.R. Cashikar A.G. Kowal A.S. Sawicki G.J. Moslehi J.J. Serpell L. Arnsdorf M.F. Lindquist S.L. Science. 2000; 289: 1317-1321Crossref PubMed Scopus (831) Google Scholar). This conformational is the rate-limiting step in the polymerization reaction (18Scheibel T. Bloom J. Lindquist S.L. Proc. Natl. Acad. Sci. U. S. A. 2004; 101: 2287-2292Crossref PubMed Scopus (81) Google Scholar) in a lag weakly on than first We that the lag phase in the polymerization of Sup35NM is shortened upon the Sup35NM but by than a first This that conformational of a nucleus is required in the reaction. In this the conformational could be by the heterologous The of RnqPD aggregates on Sup35NM polymerization was further by the of the lag on the of seed cross-seeding was only RnqPD aggregates were they were used as This on the level of Sup35NM RnqPD aggregated RnqPD Sup35NM polymerization, we the the of Sup35NM fibers on RnqPD RnqPD was polymerized in the presence of Sup35 the lag was shortened by increased of and the was than in the unseeded reaction the lag in the reaction was as as in the self-seeded at of to seed not the results of the kinetic of polymerization of RnqPD to the one for Sup35NM polymerization The lag phase in unseeded and RnqPD reactions weakly than first with RnqPD that the reaction was at a was by of Sup35NM seed reactions kinetic the of the heterologous seed was more in polymerization of RnqPD, as a of Sup35 seed was to a of by evidence of between Sup35NM and RnqPD upon cross-seeding, we Sup35NM fibers by Cross-seeded Sup35NM fibers to sprout from and and not RnqPD These fibers not from self-seeded Sup35NM fibers (13Glover J.R. Kowal A.S. Schirmer E.C. Patino M.M. Liu J.J. Lindquist S. Cell. 1997; 89: 811-819Abstract Full Text Full Text PDF PubMed Scopus (545) Google Scholar, C.Y. P. R. M. Proc. Natl. Acad. Sci. U. S. A. 1997; PubMed Scopus Google Scholar) but to associate more We the structures on the as RnqPD seed based on a morphological with the and by antibody and antibody an level of and and and to Sup35NM fibers not after overnight polymerization RnqPD to fiber-like structures the presence of fibers in the reactions suggests a between Sup35NM fibers and RnqPD In the cross-seeding formed RnqPD spherical to be with Sup35NM fibers at In samples taken at 4 Sup35NM fibers were with aggregated RnqPD that formed and to shown in fibers not appear in samples Sup35NM seed was not not RnqPD to Sup35NM fibers their than their growth at the SDS treatment of the samples in fiber-like structures to in the unseeded reaction to globular RnqPD fibers that Sup35NM seed were observed in the This is on the prion domain of Rnq1 (amino acids which is to a aggregated state in vivo (22Sondheimer N. Lindquist S. Mol. Cell. 2000; 5: 163-172Abstract Full Text Full Text PDF PubMed Google Scholar), and with of polymerization and of the by showed that RnqPD forms aggregates in vitro and with Sup35NM by a cross-seeding The sigmoidal kinetics of the RnqPD polymerization with the in a growing of amyloidogenic proteins that aggregate by a nucleated Several results suggest that RnqPD after in reaction buffer as A of RnqPD not is an of thioflavin polymerization is by the oligomers are by The of the antibody is the evidence that the amyloid an oligomeric we the oligomers by the can we they are oligomeric species were previously shown to be in of two other yeast proteins, Sup35NM J. Lindquist S. Science. 2004; PubMed Scopus Google Scholar) and Ure2 S. J. S. Biol. 2005; PubMed Scopus Google Scholar). for other amyloidogenic proteins, e.g. of G. Prusiner S.B. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar), the domain of an V.N. R. S. J. Biol. 2002; Full Text Full Text PDF PubMed Scopus Google Scholar), J.R. A. Protein Sci. 2004; PubMed Scopus Google Scholar), and the of in to fibers. RnqPD polymerization with a lag the reaction is self-seeded A lag was in self-seeded It was that conformational of to fibers the rate-limiting step 2005; PubMed Scopus Google Scholar). Based on this we that the lag in self-seeded RnqPD polymerization is the required for the of with the spherical seed The formed to spherical aggregates with growth. and the of the spherical aggregates to and spherical RnqPD not were the major structure observed in samples taken at polymerization SDS treatment the of fibers at some of the spherical aggregates are composed of fibers. the fibers observed in of samples with the spherical species amyloidogenic of RnqPD by the on the spherical species as as the of RnqPD but is by The process could be as a to RnqPD in the at the Rnq1 aggregates the [PIN+] prion in vivo have a from in We showed that RnqPD and Sup35NM cross-seed each polymerization in because the of fibers is not as for Sup35NM as for RnqPD, Sup35NM a more seed than to be a between and Sup35NM polymerization as the can the of heterologous seed e.g. the of seed is the reaction upon the polymerization of Sup35NM from the unseeded reaction and not Sup35NM (16Serio T.R. Cashikar A.G. Kowal A.S. Sawicki G.J. Moslehi J.J. Serpell L. Arnsdorf M.F. Lindquist S.L. Science. 2000; 289: 1317-1321Crossref PubMed Scopus (831) Google Scholar) and RnqPD with a lag a nucleated and the lag a a amyloidogenic was to within the context of oligomers (16Serio T.R. Cashikar A.G. Kowal A.S. Sawicki G.J. Moslehi J.J. Serpell L. Arnsdorf M.F. Lindquist S.L. Science. 2000; 289: 1317-1321Crossref PubMed Scopus (831) Google Scholar), because the at the level the be We the in reactions and and that nucleation within the oligomeric not the of protein to the is the rate-limiting step in We further that the of the nucleus is more on a as the heterologous seed shortens the lag. Such a Sup35NM in a of a and the of the of finding the amyloidogenic The of is further supported by the of aggregates from cross-seeding and RnqPD aggregates used as seed not appear to after not yet they sprout Sup35NM fibers upon cross-seeding we have evidence the cross-seeding to be the aggregate surface that The and that a surface an further In the RnqPD pre-amyloid species were observed to to Sup35NM fibers we that these aggregates are the of of an intermediate by the seed surface is as In Sup35 seed of RnqPD spherical aggregates further nucleation and the formed fibers from rapid This could not only in a lag but in a of cross-seed RnqPD polymerization The between Sup35NM and RnqPD upon cross-seeding can be used as a model of the in vivo be because in vivo is the of M.F. 2005; PubMed Scopus Google Scholar) and in an with structures that could a surface for nucleation (for a between the and Sup35 prion was S. R.D. Chernoff Y.O. Mol. Cell. Biol. PubMed Scopus Google These could the of of in vivo and, modify as and the of the the between the and unseeded prion could be increased by Sup35 with Rnq1 from [PIN+] cells the of [PSI+] Smirnov V.N. Kushnirov V.V. Ter-Avanesyan M.D. J. Biol. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar), which with in vitro an of Sup35NM to aggregated the of the appearance of [PSI+] is only with and overproduction of Sup35 (7Derkatch I.L. Bradley M.E. Zhou P. Chernoff Y.O. Liebman S.W. Genetics. 1997; 147: 507-519Crossref PubMed Google Scholar). This could be by that the is required but not to the Sup35 aggregates could be by in vivo in the observed of [PSI+] In that the de novo of a prion be potential This a of the cross-seeding as a triggering in We Lindquist for and for for RnqPD for on SDS treatment of prion and at the of at with
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